Science.gov

Sample records for pb-bi corrosion processes

  1. Corrosion erosion test of SS316 in flowing Pb Bi

    NASA Astrophysics Data System (ADS)

    Kikuchi, K.; Kurata, Y.; Saito, S.; Futakawa, M.; Sasa, T.; Oigawa, H.; Wakai, E.; Miura, K.

    2003-05-01

    Corrosion tests of austenitic stainless tube were done under flowing Pb-Bi conditions for 3000 h at 450 °C. Specimens were 316SS produced as a tubing form with 13.8 mm outer diameter, 2 mm thickness and 40 cm length. During operation, maximum temperature, temperature difference and flow velocity of Pb-Bi at the specimen were kept at 450, 50 °C, and 1 m/s, respectively. After the test, specimen and components of the loop were cut and examined by optical microscope, SEM, EDX, WDX and X-ray diffraction. Pb-Bi adhered on the surface of the specimen even after Pb-Bi was drained out to the storage tank from the circulating loop. Results differed from a stagnant corrosion test in that the specimen surface became rough and the corrosion rate was maximally 0.1 mm/3000 h. Mass transfer from the high temperature to the lower temperature area was observed: crystals of Fe-Cr were found on the tube surface in the low-temperature region. The sizes of crystals varied from 0.1 to 0.2 mm. The depositing crystals were ferrite grains and the chemical composition ratio (mass%) of Fe to Cr was 9:1.

  2. In-Situ X-ray Spectroscopic Studies of the Fundamental Chemistry of Pb and Pb-Bi Corrosion Processes at High Temperatures: Development and Assessment of Composite Corrosion Resistant Materials.

    SciTech Connect

    Carlo Segre

    2009-12-30

    Over the course of this project, we have a number of accomplishments. The following list is presented as a summary statement for the project. Specific details from previous Quarterly Reports are given. (1) We established that it is possible to use EXAFS to study the interface layer between a material and the liquid Pb overlayer. We have discovered that molybdenum grows a selflimiting oxide layer which does not spall even at the highest temperatures studied. There have been 2 publications resulting from these studies. (2) We have fabricated a high temperature environmental chamber capable of extending the Pb overlayer studies by varying the incident x-ray beam angle to perform depth profiling of the Pb layer. This chamber will continue to be available to nuclear materials program researchers who wish to use the MRCAT beam line. (3) We have developed a collaboration with researchers at the Paul Scherrer Institute to study corrosion layers on zircalloy. One publication has resulted from this collaboration and another is in progress. (4) We have developed a collaboration with Prof. G.R. Odette of UCSB in which we studied the local structure of Ti and Y in nanoclusters found in oxygen dispersion strengthened steels. There are two publications in progress form this collaboration and we have extended the project to anomalous small angle x-ray scattering as well as EXAFS. (5) We have promoted the use of EXAFS for the study of nuclear materials to the community over the past 4 years and we have begun to see an increase in demand for EXAFS from the community at the MRCAT beam line. (6) This grant was instrumental in nucleating interest in establishing a new Collaborative Access Team at the Advanced Photon Source, the Nuclear and Radiological Research CAT (NRR-CAT). The co-PI (Jeff Terry) is the lead investigator on this project and it has been approved by the APS Scientific Advisory Committee for further planning. The status of the NRR-CAT project is being discussed in a

  3. Results of steel corrosion tests in flowing liquid Pb/Bi at 420-600 °C after 2000 h

    NASA Astrophysics Data System (ADS)

    Müller, G.; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V.

    2002-02-01

    Corrosion tests were carried out on austenitic AISI 316L and 1.4970 steels and on MANET steel up to 2000 h of exposure to flowing (up to 2 m/s) Pb/Bi. The concentration of oxygen in the liquid alloy was controlled at 10 -6 wt%. Specimens consisted of tube and rod sections in original state and after alloying of Al into the surface. After 2000 h of exposure at 420 and 550 °C the specimen surfaces were covered with an intact oxide layer which provided a good protection against corrosion attack of the liquid Pb/Bi alloy. After the same time corrosion attack at 600 °C was severe at the original AISI 316L steel specimens. The alloyed specimens containing FeAl on the surface of the alloyed layer still maintained an intact oxide layer with good corrosion protection up to 600 °C.

  4. The impact of the composition of structural steels on their corrosion stability in liquid Pb-Bi at 500 and 400 °C with different oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Ilinc̆ev, Georgi; Kárník, Dalibor; Paulovic̆, Martin; Doubková, Alena

    2004-11-01

    In recent years, heavy liquid metals have found exercise as possible coolants and targets in the conversion of radioactive elements in accelerator driven systems (ADS). Liquid lead-bismuth eutectic alloy is one of candidates for this using tanks to its suitable nuclear and physical properties. Performed examination was aimed at research of compatibility choice materials for parts of ADS with liquid Pb-Bi eutectic alloy, influence of composition choice materials on their corrosion resistance, influence of temperature and oxygen content. We performed corrosion tests of 1000 h each on approximately 20 types of structural steels (austenitic, ferritic and martensitic) in convection loops with flowing Pb-Bi at 500 and 400 °C and using different oxygen concentrations. The impact of Fe, Cr, Ni, Mn, Si, Al and Mo content on the corrosion stability of these steels was measured without and after preliminary passivation through creating thin spinel or oxide layers on their surface.

  5. Strong superconducting strength in ε-PbBi microcubes

    NASA Astrophysics Data System (ADS)

    Gandhi, Ashish Chhaganlal; Wu, Sheng Yun

    2016-06-01

    Single phase ε-PbBi microcubes were synthesized using a simple thermal evaporation method. Synchrotron x-ray measurement of the crystal structure of the ε-PbBi microcubes revealed a space group of P63/mmc. Enhanced superconducting transitions were observed from the temperature dependent magnetization, showing a main diamagnetic Meissner state below a TC of ~8.66(2) K. An extremely strong superconducting strength (α=2.51(1)) and electron-phonon constant (λEP=2.25) are obtained from the modified Allen and Dynes theory, which give rise to higher TC superconductivity in this type of structure. The electron-phonon coupling to low lying phonons is found to be the leading mechanism for the observed strong-coupling superconductivity in the PbBi system.

  6. Polymorphism in PbBiOXO{sub 4} compounds (X=V, P, As): Part II-PbBiOPO{sub 4} and PbBiOAsO{sub 4} structures and characterization of related solid solutions

    SciTech Connect

    Labidi, Olfa; Roussel, Pascal; Drache, Michel Vannier, Rose-Noelle; Wignacourt, Jean-Pierre

    2008-09-15

    Reinvestigation of PbBiOXO{sub 4} (X=V, P, As) thermal behaviour revealed a phase transition for V- and P-compounds, but no transition for the As-compound. As shown by single-crystal X-ray diffraction and high-resolution neutron powder diffraction, {alpha}-PbBiOVO{sub 4} transforms to {beta}-PbBiOVO{sub 4} at 550 deg. C. The two PbBiOPO{sub 4} varieties are isomorph to the vanadate forms, while PbBiOAsO{sub 4} adopts the {beta}-type structure whatever the temperature. PbBiP{sub 1-x}OAs{sub x}O{sub 4} and PbBiV{sub 1-x}OM{sub x}O{sub 4} (M=As, P, Cr, Mn) solid solutions display both triclinic and monoclinic domains, and the {alpha}{yields}{beta} transition temperature is a function of the substitution rate. The ionic conductivity of these compounds was investigated by impedance spectroscopy. The analysis of free space in the {beta}-PbBiOVO{sub 4} structure allows to propose a one-dimensional oxygen diffusion pathway along [010] when the temperature increases. - Graphical abstract: {alpha}{yields}{beta} PbBiOV{sub 1-x}As{sub x}O{sub 4} composition dependence.

  7. Performance of New Pb-Bi Alloys for Pb-Acid Battery Applications: EIS and Polarization Study

    NASA Astrophysics Data System (ADS)

    Peixoto, Leandro C.; Bortolozo, Ausdinir D.; Garcia, Amauri; Osório, Wislei R.

    2016-06-01

    The present investigation is focused on the evaluation of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization results, associated with resulting microstructural features of two distinct as-cast Pb-Bi alloys (i.e., 1 and 2.5 wt.% Bi). EIS, potentiodynamic polarization curves, and equivalent circuits are used to analyze the corrosion behavior. The electrochemical parameters show that the corrosion resistance increases when the matrix microstructure is characterized by coarser cells when compared with finer ones. However, when a coarse cellular array is associated with increase in Bi content caused by macrosegregation during casting, the corrosion resistance decreases significantly. Bismuth modifies the anode/cathode area ratio increasing drastically the corrosion action.

  8. Liquid Li-Pb-Bi, a new tritium breeder

    SciTech Connect

    Rogers, A.G.; Benedict, B.L.; Clemmer, R.G.

    1981-01-01

    In light of their potential utility as tritium breeder-blanket materials, a study was conducted to identify and characterize low-melting phases in the lithium-lead-bismuth system. It is found that a low-melting ternary phase field did in fact exist, e.g., compositions with less than or equal to 20 atom percent lithium and Pb/Bi = 0.773 melted at or below 140/sup 0/C. In addition, the qualitative reactivity of Li-Bi-Pb alloys with water was tested, and although minimal evidence of exothermic chemical reaction was observed, a physical vapor explosion did occur in one of the tests.

  9. Polymorphism in PbBiOXO{sub 4} compounds (X=V, P, As). Part I: Crystal structures of {alpha}- and {beta}-PbBiOVO{sub 4}

    SciTech Connect

    Labidi, Olfa; Roussel, Pascal; Porcher, Florence Vannier, Rose-Noelle; Wignacourt, Jean-Pierre

    2008-09-15

    Reinvestigation of PbBiOVO{sub 4} thermal behaviour revealed a phase transition. As shown by single-crystal X-ray diffraction and high-resolution neutron powder diffraction, {alpha}-PbBiOVO{sub 4} transforms to {beta}-PbBiOVO{sub 4} at 550 deg. C. At 25 deg. C, {alpha}-PbBiOVO{sub 4} is triclinic, S.G. P-1, Z=2, with a=5.6088(3), b=7.1109(3), c=7.2978(3) A, {alpha}=108.957(2), {beta}=111.889(2), and {gamma}=94.833(2){sup o}. Above 550 deg. C, {beta}-PbBiOVO{sub 4} is monoclinic, S.G. C2/m, Z=4, with a=13.61(1), b=5.64(1), c=7.18(1) A, and {beta}=113.75(1){sup o}. Both structures are built upon (O{sub 2}Bi{sub 2}Pb{sub 2}){sub {infinity}} chains parallel to the [100] direction in the {alpha} polymorph and [001] in the {beta}-polymorph. These chains are undulated in {alpha} and linear in {beta}. In both structures, VO{sub 4} tetrahedra are organized in two sets of rows parallel to (O{sub 2}Bi{sub 2}Pb{sub 2}){sub {infinity}} chains, thus building layers of (OBiPb) sandwiched by two layers of VO{sub 4} oriented head to tail; VO{sub 4} displays different orientations in {alpha}- and {beta}-PbBiOVO{sub 4}. - Graphical abstract: PbBiOVO{sub 4} polymorphism.

  10. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  11. Improve corrosion control in refining processes

    SciTech Connect

    Kane, R.D.; Cayard, M.S.

    1995-11-01

    New guidelines show how to control corrosion and environmental cracking of process equipment when processing feedstocks containing sulfur and/or naphthenic acids. To be cost competitive refiners must be able to process crudes of opportunity. These feedstocks when processed under high temperatures and pressures and alkaline conditions can cause brittle cracks and blisters in susceptible steel-fabricated equipment. Even with advances in steel metallurgy, wet H{sub 2}S cracking continues to be a problem. New research data shows that process conditions such as temperature, pH and flowrate are key factors in the corrosion process. Before selecting equipment material, operators must understand the corrosion mechanisms present within process conditions. Several case histories investigate the corrosion reactions found when refining naphthenic crudes and operating amine gas-sweetening systems. These examples show how to use process controls, inhibitors and/or metallurgy to control corrosion and environmental cracking, to improve material selection and to extend equipment service life.

  12. Combustion system processes leading to corrosive deposits

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Rosner, D. E.

    1981-01-01

    Degradation of turbine engine hot gas path components by high temperature corrosion can usually be associated with deposits even though other factors may also play a significant role. The origins of the corrosive deposits are traceable to chemical reactions which take place during the combustion process. In the case of hot corrosion/sulfidation, sodium sulfate was established as the deposited corrosive agent even when none of this salt enters the engine directly. The sodium sulfate is formed during the combustion and deposition processes from compounds of sulfur contained in the fuel as low level impurities and sodium compounds, such as sodium chloride, ingested with intake air. In other turbine and power generation situations, corrosive and/or fouling deposits can result from such metals as potassium, iron, calcium, vanadium, magnesium, and silicon.

  13. High temperature ultrasonic transducers for imaging and measurements in a liquid Pb/Bi eutectic alloy.

    PubMed

    Kazys, Rymantas; Voleisis, Algirdas; Sliteris, Reimondas; Mazeika, Liudas; Van Nieuwenhove, Rudi; Kupschus, Peter; Abderrahim, Hamid Aït

    2005-04-01

    In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions.

  14. Development of a liquid Pb-Bi target for high-power ISOL facilities

    NASA Astrophysics Data System (ADS)

    Houngbo, D.; Bernardes, A. P.; David, J. C.; Delonca, M.; Kravalis, K.; Lahiri, S.; Losito, R.; Maglioni, C.; Marchix, A.; Mendonca, T. M.; Popescu, L.; Schumann, D.; Schuurmans, P.; Stora, T.; Vollaire, J.; Vierendeels, J.

    2016-06-01

    This paper describes some R&D activities conducted in support of the design and safe operation of a high-power liquid Pb-Bi target within the LIEBE (Liquid Eutectic Lead Bismuth Loop Target for EURISOL) project. The target material is lead bismuth eutectic (LBE) which also acts as a primary coolant. As a consequence of interaction of the highly pulsed 1.4-GeV protons at ISOLDE with the target, heat powers of the order of 2 GW would be instantaneously deposited in the target during a bunch. Considerable R&D effort is thus required to demonstrate its continued coolability and structural integrity. This paper mainly reports on the conjugate flow (CFD) and heat deposition (Monte Carlo) calculations, not accounting for Fluid-Structure Interactions.

  15. MYRRHA, a Pb-Bi experimental ADS: specific approach to radiation protection aspects.

    PubMed

    Abderrahim, H Aït; Aoust, Th; Malambu, E; Sobolev, V; Van Tichelen, K; De Bruyn, D; Maes, D; Haeck, W; Van den Eynde, G

    2005-01-01

    Since 1998, SCK*CEN, in partnership with IBA s.a. and many European research laboratories, is designing a multipurpose accelerator driven system (ADS) for Research and Development (R&D) applications-MYRRHA-and is conducting an associated R&D support programme. MYRRHA is an ADS under development at Mol in Belgium and is aiming to serve as a basis for the European experimental ADS to provide protons and neutrons for various R&D applications. It consists of a proton accelerator delivering a 350 MeV x 5 mA proton beam to a liquid Pb-Bi spallation target that in turn couples to a Pb-Bi cooled, subcritical fast core. In the first stage, the project focuses mainly on demonstration of the ADS concept, safety research on sub-critical systems and nuclear waste transmutation studies. In a later stage, the device will also be dedicated to research on structural materials, nuclear fuel, liquid metal technology and associated aspects, and on sub-critical reactor physics. Subsequently, it will be used for research on applications such as radioisotope production. A first preliminary conceptual design file of MYRRHA was completed by the end of 2001 and has been reviewed by an International Technical Guidance Committee, which concluded that there are no show stoppers in the project and even though some topics such as the safety studies and the fuel qualification need to be addressed more deeply before concluding it. In this paper, we are reporting on the state-of-the art of the MYRRHA project at the beginning of 2004 and in particular on the radiation shielding assessment and the radiation protection particular aspects through a remote handling operation approach in order to minimise the personnel exposure to radiation.

  16. Corrosion resistant process piping changes in economics

    SciTech Connect

    Lain, E.H. Jr.

    1996-07-01

    In recent years, the process piping industry has seen dramatic changes occur in corrosion resistant materials. Some changes have occurred in the form of new and modified materials becoming available. However, the most dramatic changes have occurred in the pricing of some older and well known materials. These economic changes have been dramatic and quick, so much so that the old established budget pricing ``rules of thumb`` used for many years to estimate piping projects are no longer valid. In many instances, the prices of some premium metals (titanium, for example) are now on a comparatively equal basis even with high alloys when all factors including densities, special fabrication requirements and service life are taken into account. The purpose of this paper is to discuss some commonly encountered corrosion resistant piping materials, a brief summary of their chemical and mechanical properties and usage. However, the focus of the paper presented will be economic. It will detail the current raw material prices for high alloys including duplex stainless steels, nickel and nickel alloys, Hastelloys+, as well as the reactive metals, zirconium and titanium. In addition, a typical fabricated piping spool in various diameters will be estimated for all of the above metals and the results plotted in graphical format for quick comparison. Last, a quick method will be presented to estimate as fabricated piping costs if the base material price for pipe is known.

  17. CORROSION ISSUES ASSOCIATED WITH AUSTENITIC STAINLESS STEEL COMPONENTS USED IN NUCLEAR MATERIALS EXTRACTION AND SEPARATION PROCESSES

    SciTech Connect

    Mickalonis, J.; Louthan, M.; Sindelar, R.

    2012-12-17

    This paper illustrated the magnitude of the systems, structures and components used at the Savannah River Site for nuclear materials extraction and separation processes. Corrosion issues, including stress corrosion cracking, pitting, crevice corrosion and other corrosion induced degradation processes are discussed and corrosion mitigation strategies such as a chloride exclusion program and corrosion release testing are also discussed.

  18. Microbial iron respiration: impacts on corrosion processes.

    PubMed

    Lee, A K; Newman, D K

    2003-08-01

    In this review, we focus on how biofilms comprising iron-respiring bacteria influence steel corrosion. Specifically, we discuss how biofilm growth can affect the chemistry of the environment around the steel at different stages of biofilm development, under static or dynamic fluid regimes. We suggest that a mechanistic understanding of the role of biofilm metabolic activity may facilitate corrosion control.

  19. Design Study of Small Pb-Bi Cooled Modified Candle Reactors

    NASA Astrophysics Data System (ADS)

    Su'ud, Zaki; Sekimoto, H.

    2010-06-01

    In this study application of modified CANDLE burnup scheme based long life Pb-Bi Cooled Fast Reactors for small long life reactors with natural Uranium as Fuel Cycle Input has been performed. The reactor cores are subdivided into several parts with the same volume in the axial directions. The natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2, and 10 years after that it is shifted to region 3. This concept is applied to all regions, i.e. shifted the core of I'th region into I+1 region after the end of 10 years burn-up cycle. The first region 1 is filled by fresh natural uranium fuel. Compared to the previous works, in a smaller reactor core the criticality need to be considered more carefully especially at the beginning of life. As an optimized design, a core of 85 cm radius and 150 cm height with 300 MWt power are selected. This core can be operated 10 years without refueling or fuel shuffling. The average discharge burn-up is 350 GWd/ton HM.

  20. Degradation Modeling of 2024 Aluminum Alloy During Corrosion Process

    NASA Astrophysics Data System (ADS)

    Pidaparti, Ramana M.; Aghazadeh, Babak Seyed

    2011-04-01

    Corrosion is one of the most damaging mechanisms in aluminum alloys used in aerospace engineering structures. In this article, the degradation behavior of AA 2024-T3 as a function of time under corrosive conditions is studied through experiments and modeling. Corrosion experiments were conducted on AA 2024-T3 specimens under controlled electrochemical conditions. The chemical element alloy map was investigated through EDS technique for evaluation purposes. Based on the experimental data, an analytical model is developed relating the material loss to the degradation during the corrosion process. The analytical model uses genetic algorithms (GAs) to map the relationship through optimization. The results obtained from GAs were compared with a standard non-linear regression model. The results obtained indicate that a quadratic relationship exists in time between the material loss due to corrosion and the degradation behavior of the alloy. Based on the good results obtained, the present approach of degradation modeling can be extended to other metals.

  1. CORROSION PROCESS IN REINFORCED CONCRETE IDENTIFIED BY ACOUSTIC EMISSION

    NASA Astrophysics Data System (ADS)

    Kawasaki, Yuma; Kitaura, Misuzu; Tomoda, Yuichi; Ohtsu, Masayasu

    Deterioration of Reinforced Concrete (RC) due to salt attack is known as one of serious problems. Thus, development of non-destructive evaluation (NDE) techniques is important to assess the corrosion process. Reinforcement in concrete normally does not corrode because of a passive film on the surface of reinforcement. When chloride concentration at reinfo rcement exceeds the threshold level, the passive film is destroyed. Thus maintenance is desirable at an early stage. In this study, to identify the onset of corrosion and the nucleation of corrosion-induced cracking in concrete due to expansion of corrosion products, continuous acoustic emission (AE) monitoring is applied. Accelerated corrosion and cyclic wet and dry tests are performed in a laboratory. The SiGMA (Simplified Green's functions for Moment tensor Analysis) proce dure is applied to AE waveforms to clarify source kinematics of micro-cracks locations, types and orientations. Results show that the onset of corrosion and the nu cleation of corrosion-induced cracking in concrete are successfully identified. Additionally, cross-sections inside the reinforcement are observed by a scanning electron microscope (SEM). From these results, a great promise for AE techniques to monitor salt damage at an early stage in RC structures is demonstrated.

  2. Study on neutronic of very small Pb - Bi cooled no-onsite refueling nuclear power reactor (VSPINNOR)

    SciTech Connect

    Arianto, Fajar; Su'ud, Zaki; Zuhair

    2014-09-30

    A conceptual design study on Very Small Pb-Bi No-Onsite Refueling Cooled Nuclear Reactor (VSPINNOR) with Uranium nitride fuel using MCNPX program has been performed. In this design the reactor core is divided into three regions with different enrichment. At the center of the core is laid fuel without enrichment (internal blanket). While for the outer region using fuel enrichment variations. VSPINNOR fast reactor was operated for 10 years without refueling. Neutronic analysis shows optimized result of VSPINNOR has a core of 50 cm radius and 100 cm height with 300 MWth thermal power output at 60% fuel fraction that can be operated 18 years without refueling or fuel shuffling.

  3. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    SciTech Connect

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  4. Superconductivity and chemical composition of the high-Tc phase (Tc = 111 K) in the Sb-Pb-Bi-Sr-Ca-Cu-O system

    NASA Astrophysics Data System (ADS)

    Kijima, Naota; Gronsky, Ronald; McKernan, Steffen K.; Endo, Hozumi; Oguri, Yasuo

    1991-01-01

    A superconducting phase with a critical temperature of 111 K in the Sb-Pb-Bi-Sr-Ca-Cu-O system has been synthesized by means of a long firing period. Its crystal structure is similar to the high-Tc phase (107 K) in the Pb-Bi-Sr-Ca-Cu-O system, and its average chemical composition is 4.3, 2.6, 19.2, 21.4, 15.8 and 36.9 percent for Sb, Pb, Bi, Sr, Ca, and Cu, respectively. The summation of the Sb concentration and the Ca concentration is approximately the same for all the samples of this phase, implying that Sb substitutes for Ca, and oxygen atoms are introduced to compensate the oxygen deficiency in the central Cu-O layer sandwiched by the two Ca layers in the crystal structure of the high-Tc phase.

  5. Aspects of two corrosion processes relevant to military hardware

    SciTech Connect

    Braithwaite, J.W.; Buchheit, R.G.

    1997-11-01

    Corrosion is a leading material degradation mode observed in many military systems. This report contains a description of a small project that was performed to allow some of the important electrochemical aspects of two distinct and potentially relevant degradation modes to be better understood: environmentally assisted cracking (EAC) of aluminum alloys and corrosion in moist salt. Two specific and respective tasks were completed: (A) the characterization of the effect of aluminum microstructural variability on its susceptibility to EAC, and (B) the development of experimental and analytical techniques that can be used to identify the factors and processes that influence the corrosivity of moist salt mixtures. The resultant information constitutes part of the basis needed to ultimately predict component reliability and/or possibly to identify techniques that could be used to control corrosion in critical components. In Task A, a physical model and related understanding for the relevant degradation processes were formulated. The primary result from Task B included the identification and qualitative validation of a methodology for determining the corrosivity of salt mixtures. A detailed compilation of the results obtained from each of these two diverse tasks is presented separately in the body of this report.

  6. The Development and Production of a Functionally Graded Composite for Pb-Bi Service

    SciTech Connect

    Ballinger, Ronald G

    2011-08-01

    A material that resists lead-bismuth eutectic (LBE) attack and retains its strength at 700°C would be an enabling technology for LBE-cooled reactors. No single alloy currently exists that can economically meet the required performance criteria of high strength and corrosion resistance. A Functionally Graded Composite (FGC) was developed with layers engineered to perform these functions. F91 was chosen as the structural layer of the composite for its strength and radiation resistance. Fe-12Cr-2Si, an alloy developed from previous work in the Fe-Cr-Si system, was chosen as the corrosion-resistant cladding layer because of its chemical similarity to F91 and its superior corrosion resistance in both oxidizing and reducing environments. Fe-12Cr-2Si experienced minimal corrosion due to its self-passivation in oxidizing and reducing environments. Extrapolated corrosion rates are below one micron per year at 700ï°C. Corrosion of F91 was faster, but predictable and manageable. Diffusion studies showed that 17 microns of the cladding layer will be diffusionally diluted during the three year life of fuel cladding. 33 microns must be accounted for during the sixty year life of coolant piping. 5 cm coolant piping and 6.35 mm fuel cladding preforms were produced on a commercial scale by weld-overlaying Fe-12Cr-2Si onto F91 billets and co-extruding them. An ASME certified weld was performed followed by the prescribed quench-and-tempering heat treatment for F91. A minimal heat affected zone was observed, demonstrating field weldability. Finally, corrosion tests were performed on the fabricated FGC at 700ï°C after completely breaching the cladding in a small area to induce galvanic corrosion at the interface. None was observed. This FGC has significant impacts on LBE reactor design. The increases in outlet temperature and coolant velocity allow a large increase in power density, leading to either a smaller core for the same power rating or more power output for the same size

  7. Corrosion study in the chemical air separation (MOLTOX trademark ) process

    SciTech Connect

    Kang, Doohee; Wong, Kai P.; Archer, R.A.; Cassano, A.A.

    1988-12-01

    This report presents the results of studies aimed at solving the corrosion problems encountered during operation of the MOLTOX{trademark} pilot plant. These studies concentrated on the screening of commercial and developmental alloys under conditions simulating operation conditions in this high temperature molten salt process. Process economic studies were preformed in parallel with the laboratory testing to ensure that an economically feasible solution would be achieved. In addition to the above DOE co-funded studies, Air Products and Chemicals pursued proprietary studies aimed at developing a less corrosive salt mixture which would potentially allow the use of chemurgically available alloys such as stainless steels throughout the system. These studies will not be reported here; however, the results of corrosion tests in the new less corrosive salt mixtures are reported. Because our own studies on salt chemistry impacts heavily on the overall process and thereby has an influence on the experimental work conducted under this contract, some of the studies discussed here were impacted by our own proprietary data. Therefore, the reasons behind some of the experiments presented herein will not be explained because that information is proprietary to Air Products. 14 refs., 42 figs., 21 tabs.

  8. Numerical Modeling of High-Temperature Corrosion Processes

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    1995-01-01

    Numerical modeling of the diffusional transport associated with high-temperature corrosion processes is reviewed. These corrosion processes include external scale formation and internal subscale formation during oxidation, coating degradation by oxidation and substrate interdiffusion, carburization, sulfidation and nitridation. The studies that are reviewed cover such complexities as concentration-dependent diffusivities, cross-term effects in ternary alloys, and internal precipitation where several compounds of the same element form (e.g., carbides of Cr) or several compounds exist simultaneously (e.g., carbides containing varying amounts of Ni, Cr, Fe or Mo). In addition, the studies involve a variety of boundary conditions that vary with time and temperature. Finite-difference (F-D) techniques have been applied almost exclusively to model either the solute or corrodant transport in each of these studies. Hence, the paper first reviews the use of F-D techniques to develop solutions to the diffusion equations with various boundary conditions appropriate to high-temperature corrosion processes. The bulk of the paper then reviews various F-D modeling studies of diffusional transport associated with high-temperature corrosion.

  9. Preliminary safety analysis of Pb-Bi cooled 800 MWt modified CANDLE burn-up scheme based fast reactors

    NASA Astrophysics Data System (ADS)

    Su'ud, Zaki; Sekimoto, H.

    2014-09-01

    Pb-Bi Cooled fast reactors with modified CANDLE burn-up scheme with 10 regions and 10 years cycle length has been investigated from neutronic aspects. In this study the safety aspect of such reactors have been investigated and discussed. Several condition of unprotected loss of flow (ULOF) and unprotected rod run-out transient over power (UTOP) have been simulated and the results show that the reactors excellent safety performance. At 80 seconds after unprotected loss of flow condition, the core flow rate drop to about 25% of its initial flow and slowly move toward its natural circulation level. The maximum fuel temperature can be managed below 1000°C and the maximum cladding temperature can be managed below 700°C. The dominant reactivity feedback is radial core expansion and Doppler effect, followed by coolant density effect and fuel axial expansion effect.

  10. Preliminary safety analysis of Pb-Bi cooled 800 MWt modified CANDLE burn-up scheme based fast reactors

    SciTech Connect

    Su'ud, Zaki; Sekimoto, H.

    2014-09-30

    Pb-Bi Cooled fast reactors with modified CANDLE burn-up scheme with 10 regions and 10 years cycle length has been investigated from neutronic aspects. In this study the safety aspect of such reactors have been investigated and discussed. Several condition of unprotected loss of flow (ULOF) and unprotected rod run-out transient over power (UTOP) have been simulated and the results show that the reactors excellent safety performance. At 80 seconds after unprotected loss of flow condition, the core flow rate drop to about 25% of its initial flow and slowly move toward its natural circulation level. The maximum fuel temperature can be managed below 1000°C and the maximum cladding temperature can be managed below 700°C. The dominant reactivity feedback is radial core expansion and Doppler effect, followed by coolant density effect and fuel axial expansion effect.

  11. Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor

    NASA Astrophysics Data System (ADS)

    Afifah, Maryam; Miura, Ryosuke; Su'ud, Zaki; Takaki, Naoyuki; Sekimoto, H.

    2015-09-01

    Fast Breeder Reactor had been interested to be developed over the world because it inexhaustible source energy, one of those is CANDLE reactor which is have strategy in burn-up scheme, need not control roads for control burn-up, have a constant core characteristics during energy production and don't need fuel shuffling. The calculation was made by basic reactor analysis which use Sodium coolant geometry core parameter as a reference core to study on minimum core reactor radius of CANDLE for long life Pb-Bi cooled, also want to perform pure coolant effect comparison between LBE and sodium in a same geometry design. The result show that the minimum core radius of Lead Bismuth cooled CANDLE is 100 cm and 500 MWth thermal output. Lead-Bismuth coolant for CANDLE reactor enable to reduce much reactor size and have a better void coefficient than Sodium cooled as the most coolant for FBR, then we will have a good point in safety analysis.

  12. The effects of ion gun beam voltage on the electrical characteristics of NbCN/PbBi edge junctions

    NASA Technical Reports Server (NTRS)

    Lichtenberger, A. W.; Feldman, M. J.; Mattauch, R. J.; Cukauskas, E. J.

    1989-01-01

    The authors have succeeded in fabricating high-quality submicron NbCN edge junctions using a technique which is commonly used to make Nb edge junctions. A modified commercial ion gun was used to cut an edge in SiO2/NbCN films partially covered with photoresist. An insulating barrier was then formed on the exposed edge by reactive ion beam oxidation, and a counterelectrode of PbBi was deposited. The electrical quality of the resulting junctions was found to be strongly influenced by the ion beam acceleration voltages used to cut the edge and to oxidize it. For low ion beam voltages, the junction quality parameter was as high as Vm = 55 mV (measured at 3 mV), but higher ion beam voltages yielded strikingly poorer quality junctions. In light of the small coherence length of NbN, the dependence of the electrical characteristics on ion beam voltage is presumably due to mechanical damage of the NbCN surface. In contrast, for similar ion beam voltages, no such dependence was found for Nb edge junctions.

  13. Study on core radius minimization for long life Pb-Bi cooled CANDLE burnup scheme based fast reactor

    SciTech Connect

    Afifah, Maryam Su’ud, Zaki; Miura, Ryosuke; Takaki, Naoyuki; Sekimoto, H.

    2015-09-30

    Fast Breeder Reactor had been interested to be developed over the world because it inexhaustible source energy, one of those is CANDLE reactor which is have strategy in burn-up scheme, need not control roads for control burn-up, have a constant core characteristics during energy production and don’t need fuel shuffling. The calculation was made by basic reactor analysis which use Sodium coolant geometry core parameter as a reference core to study on minimum core reactor radius of CANDLE for long life Pb-Bi cooled, also want to perform pure coolant effect comparison between LBE and sodium in a same geometry design. The result show that the minimum core radius of Lead Bismuth cooled CANDLE is 100 cm and 500 MWth thermal output. Lead-Bismuth coolant for CANDLE reactor enable to reduce much reactor size and have a better void coefficient than Sodium cooled as the most coolant for FBR, then we will have a good point in safety analysis.

  14. Corrosion-Resistant Container for Molten-Material Processing

    NASA Technical Reports Server (NTRS)

    Stern, Theodore G.; McNaul, Eric

    2010-01-01

    In a carbothermal process, gaseous methane is passed over molten regolith, which is heated past its melting point to a temperature in excess of 1,625 C. At this temperature, materials in contact with the molten regolith (or regolith simulant) corrode and lose their structural properties. As a result, fabricating a crucible to hold the molten material and providing a method of contact heating have been problematic. Alternative containment approaches use a large crucible and limit the heat zone of the material being processed, which is inefficient because of volume and mass constraints. Alternative heating approaches use non-contact heating, such as by laser or concentrated solar energy, which can be inefficient in transferring heat and thus require higher power heat sources to accomplish processing. The innovation is a combination of materials, with a substrate material having high structural strength and stiffness and high-temperature capability, and a coating material with a high corrosion resistance and high-temperature capability. The material developed is a molybdenum substrate with an iridium coating. Creating the containment crucible or heater jacket using this material combination requires only that the molybdenum, which is easily processed by conventional methods such as milling, electric discharge machining, or forming and brazing, be fabricated into an appropriate shape, and that the iridium coating be applied to any surfaces that may come in contact with the corrosive molten material. In one engineering application, the molybdenum was fashioned into a container for a heat pipe. Since only the end of the heat pipe is used to heat the regolith, the container has a narrowing end with a nipple in which the heat pipe is snugly fit, and the external area of this nipple, which contacts the regolith to transfer heat into it, is coated with iridium. At the time of this reporting, no single material has been found that can perform the functions of this combination

  15. Thermodynamic investigations on materials corrosion in some industrial and environmental processes.

    PubMed

    Shi, Pingfang; Engström, Anders; Sundman, Bo

    2011-06-01

    For better understanding of corrosion schemes and corrosion mechanisms of a wide range of steels/Fe-alloys, Ni-/NiFe-/Co-superalloys, Al-/Mg-/Ti-/Zr-/Sn-/Cu-/Zn-alloys, electronic-packing alloys, medical-instrument alloys and other materials, under various corrosive environments (such as aqueous solutions, non-aqueous solutions, molten salts, high-temperature gases, etc.) during production/application processes and experimental observations, the Thermo-Calc software/database/programming-interface package can be used. This article is aimed at presenting some application examples of thermodynamic calculations/simulations in some specific areas: aqueous corrosions of stainless steels and other alloys, and of high-performance corrosion-resistant materials (HPCRM); molten salt corrosions of stainless steels and high-temperature alloys; high-temperature gaseous corrosions of steels/alloys; formations of oxide-coated protective layers on steel/alloy surfaces; and emergence conditions during oxidation of steels/alloys.

  16. Two-dimensional quantification of the corrosion process in metal surfaces using digital speckle pattern interferometry

    SciTech Connect

    Andres, N.; Lobera, J.; Arroyo, M. P.; Angurel, L. A.

    2011-04-01

    The applicability of digital speckle pattern interferometry (DSPI) to the analysis of surface corrosion processes has been evaluated by studying the evolution of an Fe surface immersed in sulfuric acid. This work describes the analysis process required to obtain quantitative information about the corrosion process. It has been possible to evaluate the corrosion rate, and the results agree with those derived from the weight loss method. In addition, a two-dimensional analysis has been applied, showing that DSPI measurements can be used to extract information about the corrosion rate at any region of the surface.

  17. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    SciTech Connect

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun; Yeom, Jong-taek; Kim, Jae-il; Nam, Tae-hyun

    2013-12-15

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (

  18. Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure and method of processing

    DOEpatents

    Brown, Jr., Jesse J.; Hirschfeld, Deidre A.; Li, Tingkai

    1993-12-07

    Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

  19. Corrosion and failure processes in high-level waste tanks

    SciTech Connect

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L.

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  20. Pb-Bi-Ag-Cu-(Hg) chemistry of galena and some associated sulfosalts. A review and some new data from Colorado California and Pennsylvania

    USGS Publications Warehouse

    Foord, Eugene E.; Shawe, Daniel R.

    1989-01-01

    Galena, associated with Pb-Bi-Ag sulfosalts and simple sulfides, contains varied amounts of Ag and Bi in the Dandy vein system, Idarado mine, Ouray, Colorado; the Jackass mine, Darwin District, California; and the Leadville district, Colorado. Silver- and bismuth-bearing galena associated with minor amounts of pyrite, chalcopyrite and sphalerite occur at the Pequea mine, Lancaster County, Pennsylvania. Ag and Bi contents in the Dandy suite of galena range from about 1.4 to 3.4 and 2.5 to 6.5 wt.% respectively, and are comparable or lower in galena from the other localities. Exsolved matildite is present in galena from the Dandy, Jackass and Leadville localities. The presence in significant amounts of both Ag and Bi in a Pb-rich sulfide system is necessary for formation of PbSss (galena solid-solution). If Ag (especially) and Bi (to a lesser extent) are absent, the galena formed will be essentially pure PbS. Some minor Sb may substitute for Bi. Compositional data for all of the galena samples are in agreement with a previously proposed linear relationship between a and Ag-Bi(Sb) content. Matildite and seven additional Pb-Bi-Ag-Cu sulfosalts have been identified from the Dandy vein system, based on electron-microprobe analyses and some X-ray powder-diffraction data.

  1. Environmental Cracking of Corrosion Resistant Alloys in the Chemical Process Industry - A Review

    SciTech Connect

    Rebak, R B

    2006-12-04

    A large variety of corrosion resistant alloys are used regularly in the chemical process industry (CPI). The most common family of alloys include the iron (Fe)-based stainless steels, nickel (Ni) alloys and titanium (Ti) alloys. There also other corrosion resistant alloys but their family of alloys is not as large as for the three groups mentioned above. All ranges of corrosive environments can be found in the CPI, from caustic solutions to hot acidic environments, from highly reducing to highly oxidizing. Stainless steels are ubiquitous since numerous types of stainless steels exist, each type tailored for specific applications. In general, stainless steels suffer stress corrosion cracking (SCC) in hot chloride environments while high Ni alloys are practically immune to this type of attack. High nickel alloys are also resistant to caustic cracking. Ti alloys find application in highly oxidizing solutions. Solutions containing fluoride ions, especially acid, seem to be aggressive to almost all corrosion resistant alloys.

  2. Corrosion barriers processed by Al electroplating and their resistance against flowing Pb-15.7Li

    NASA Astrophysics Data System (ADS)

    Krauss, Wolfgang; Konys, Jürgen; Wulf, Sven-Erik

    2014-12-01

    In the HCLL blanket design, ferritic-martensitic steels are in direct contact with the flowing liquid breeder Pb-15.7Li and have to withstand severe corrosion attack. Beyond corrosion, T-permeation from the breeder into the RAFM-steels is also an important issue and has to be reduced significantly. Earlier work showed that Al-based coatings can act as barriers for both, however, applied processes e.g. HDA or VPS exhibited strong drawbacks in the past. Meanwhile new industrial relevant coating processes, using electroplating technology are under development and called ECA (electrochemical aluminization) and ECX (electrochemical deposition from ionic liquids) process. In this study electrochemically Al-coated and heat-treated Eurofer samples were tested in PICOLO loop for exposure times up to 12,000 h (ECA) and 2000 h (first results ECX) respectively to determine corrosion properties in flowing Pb-15.7Li (550 °C, 0.1 m/s). Cross section analysis afterward corrosion testing proved the ability of thin Al-based barriers made by electrochemical techniques to protect the bare Eurofer from corrosion attack even at exposure times of 12,000 h. Determined radial corrosion rates lay between 10 and 20 μm/a. First results for ECX coated samples (2000 h) revealed more homogeneous corrosion behavior of the barrier layer itself compared to ECA.

  3. Corrosion resistance properties of superhydrophobic copper surfaces fabricated by one-step electrochemical modification process

    NASA Astrophysics Data System (ADS)

    Huang, Ying; Sarkar, D. K.; Gallant, Danick; Chen, X.-Grant

    2013-10-01

    Superhydrophobic copper surfaces have been prepared by a one-step electrochemical modification process in an ethanolic stearic acid solution. In this work, the corrosion properties of hydrophobic copper surface and superhydrophobic copper surfaces were analyzed by means of electrochemical analyses and compared with that of as-received bare copper substrate. The decrease of corrosion current density (icorr) as well as the increase of polarization resistance (Rp) obtained from potentiodynamic polarization curves revealed that the superhydrophobic film on the copper surfaces improved the corrosion resistance performance of the copper substrate.

  4. Determination of critical length scales for corrosion processes using microelectroanalytical techniques.

    SciTech Connect

    Zavadil, Kevin Robert; Wall, Frederick Douglas

    2004-03-01

    A key factor in our ability to produce and predict the stability of metal-based macro- to nano-scale structures and devices is a fundamental understanding of the localized nature of corrosion. Corrosion processes where physical dimensions become critical in the degradation process include localized corrosion initiation in passivated metals, microgalvanic interactions in metal alloys, and localized corrosion in structurally complex materials like nanocrystalline metal films under atmospheric and inundated conditions. This project focuses on two areas of corrosion science where a fundamental understanding of processes occurring at critical dimensions is not currently available. Sandia will study the critical length scales necessary for passive film breakdown in the inundated aluminum (Al) system and the chemical processes and transport in ultra-thin water films relevant to the atmospheric corrosion of nanocrystalline tungsten (W) films. Techniques are required that provide spatial information without significantly perturbing or masking the underlying relationships. Al passive film breakdown is governed by the relationship between area of the film sampled and its defect structure. We will combine low current measurements with microelectrodes to study the size scale required to observe a single initiation event and record electrochemical breakdown events. The resulting quantitative measure of stability will be correlated with metal grain size, secondary phase size and distribution to understand which metal properties control stability at the macro- and nano-scale. Mechanisms of atmospheric corrosion on W are dependent on the physical dimensions and continuity of adsorbed water layers as well as the chemical reactions that take place in this layer. We will combine electrochemical and scanning probe microscopic techniques to monitor the chemistry and resulting material transport in these thin surface layers. A description of the length scales responsible for driving the

  5. Processing and Probability Analysis of Pulsed Terahertz NDE of Corrosion under Shuttle Tile Data

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.; Seebo, Jeffrey P.; Ely, Thomas M.

    2009-01-01

    This paper examines data processing and probability analysis of pulsed terahertz NDE scans of corrosion defects under a Shuttle tile. Pulsed terahertz data collected from an aluminum plate with fabricated corrosion defects and covered with a Shuttle tile is presented. The corrosion defects imaged were fabricated by electrochemically etching areas of various diameter and depth in the plate. In this work, the aluminum plate echo signal is located in the terahertz time-of-flight data and a threshold is applied to produce a binary image of sample features. Feature location and area are examined and identified as corrosion through comparison with the known defect layout. The results are tabulated with hit, miss, or false call information for a probability of detection analysis that is used to identify an optimal processing threshold.

  6. Effect of manufacturing process sequence on the corrosion resistance characteristics of coated metallic bipolar plates

    NASA Astrophysics Data System (ADS)

    Dur, Ender; Cora, Ömer Necati; Koç, Muammer

    2014-01-01

    Metallic bipolar plate (BPP) with high corrosion and low contact resistance, durability, strength, low cost, volume, and weight requirements is one of the critical parts of the PEMFC. This study is dedicated to understand the effect of the process sequence (manufacturing then coating vs. coating then manufacturing) on the corrosion resistance of coated metallic bipolar plates. To this goal, three different PVD coatings (titanium nitride (TiN), chromium nitride (CrN), zirconium nitride (ZrN)), with three thicknesses, (0.1, 0.5, 1 μm) were applied on BPPs made of 316L stainless steel alloy before and after two types of manufacturing (i.e., stamping or hydroforming). Corrosion test results indicated that ZrN coating exhibited the best corrosion protection while the performance of TiN coating was the lowest among the tested coatings and thicknesses. For most of the cases tested, in which coating was applied before manufacturing, occurrence of corrosion was found to be more profound than the case where coating was applied after manufacturing. Increasing the coating thickness was found to improve the corrosion resistance. It was also revealed that hydroformed BPPs performed slightly better than stamped BPPs in terms of the corrosion behavior.

  7. Texture analysis of monofilamentary, Ag-sheathed (Pb,Bi) 2Sr 2Ca 2Cu 3O x tapes by electron backscatter diffraction (EBSD)

    NASA Astrophysics Data System (ADS)

    Koblischka-Veneva, A.; Koblischka, M. R.; Qu, T.; Han, Z.; Mücklich, F.

    2008-02-01

    Using automated orientation imaging, the grain orientations and texture of monofilamentary, Ag-sheathed (Pb,Bi) 2Sr 2Ca 2Cu 3O x (Bi-2223) tape is analysed in detail by means of electron backscatter diffraction (EBSD). The achieved high image quality of the Kikuchi patterns enables multi-phase scans including Bi-2223, Bi 2Sr 2CaCu 2O x, Bi 2Sr 2CuO x, (Sr,Ca) 14Cu 24O 41 and Ag to be performed. Two areas are selected for the EBSD analysis, one close to the silver sheath, the other located in the center of the sample. The grain orientation maps are presented for each phase separately allowing a new insight into the microtexture of Ag-sheathed Bi-2223 tapes. Furthermore, the EBSD analysis provides the possibility for a misorientation angle analysis within each individual phase.

  8. Transport properties of the SnBi{sub 2}Te{sub 4}–PbBi{sub 2}Te{sub 4} solid solution

    SciTech Connect

    Pan, Lin; Li, Jing; Berardan, David Dragoe, Nita

    2015-05-15

    We report on the electrical and thermal transport properties of the Sn{sub 1−x}Pb{sub x}Bi{sub 2}Te{sub 4} series and we discuss the potential of these materials for thermoelectric conversion applications. From the evolution of the XRD patterns, we can confidently conclude that a complete solid solution exists between SnBi{sub 2}Te{sub 4} and PbBi{sub 2}Te{sub 4}, with no miscibility gap. A crossover from p-type conduction in Sn-rich samples to n-type conduction in Pb-rich ones has been observed, with a transition between x=0.3 and 0.4. A concomitant increase of the electrical resistivity and of the Seebeck coefficient has been observed in the solid solution, which leads to almost constant values of the thermoelectric power factor. Moreover, the thermal conductivity is slightly reduced in the solid solution. The best figure of merit ZT values at room temperature have been observed for p-type Sn{sub 0.8}Pb{sub 0.2}Bi{sub 2}Te{sub 4} with ZT=0.25 and for n-type Sn{sub 0.3}Pb{sub 0.7}Bi{sub 2}Te{sub 4} with ZT=0.15. - Graphical abstract: Seebeck coefficient in (Pb/Sn)Bi{sub 2}Te{sub 4} solid solution. - Highlights: • A complete solid solution exists between PbBi{sub 2}Te{sub 4} and SnBi{sub 2}Te{sub 4.} • A crossover between p-type and n-type is observed for 0.3

  9. Correlation of Process Data and Electrochemical Noise to Assess Kraft Digester Corrosion: Kamloops Experiment

    SciTech Connect

    Pawel, SJ

    2002-05-09

    Electrochemical noise (ECN) probes were deployed in a carbon steel continuous kraft digester at five locations roughly equi-spaced from top to bottom of the vessel. Current and potential noise, the temperature at each probe location, and the value of about 60 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously for a period of one year. Historical vessel inspection data, including inspections accomplished immediately prior to and immediately following probe deployment, and post-test evaluation of the probe components were used to assess/compare corrosion indications from the probes with physical changes in wall thickness and corrosion patterns on the digester shell. The results indicate that furnish composition is a significant variable influencing digester corrosion, with increasing amounts of Douglas fir in the nominal furnish correlating directly with increased corrosion activity on the ECN probes. All five probes detected changes in furnish composition approximately simultaneously, indicating rapid chemical communication through the liquor, but the effect was strongest and persisted longest relatively high in the digester. The ECN probes also indicate significant corrosion activity occurred at each probe position during shutdown/restart transients. Little or no correlation between ECN probe corrosion activity and other operational variables was observed. Post-test evaluation of the probes confirmed general corrosion of a magnitude that closely agreed with corrosion current sums calculated for each probe over the exposure period and with historical average corrosion rates for the respective locations. Further, no pitting was observed on any of the electrodes, which is consistent with the ECN data, relevant polarization curves developed for steel in liquor removed from the digester, and the post-test inspection of the digester.

  10. Corrosion Properties of Polydopamine Coatings Formed in One-Step Immersion Process on Magnesium.

    PubMed

    Singer, Ferdinand; Schlesak, Magdalena; Mebert, Caroline; Höhn, Sarah; Virtanen, Sannakaisa

    2015-12-01

    Polydopamine layers were polymerized directly from Tris(hydroxymethyl)aminomethane-buffered solution in a one-step immersion process onto magnesium surface. Scanning electron microscopy showed successful formation of a ∼1 μm thick layer. ASTM D3359-09 "Tape test" revealed excellent adhesion of the layer. X-ray induced photoelectron spectroscopy and Fourier transform infrared spectroscopy verified the presence of polydopamine on the surface. Corrosion measurements were performed in 0.1 M NaCl solution investigating the influence of coating parameters: dopamine concentration, immersion time, solution pH, and immersion angle. Tafel analysis revealed strong improvement of corrosion behavior compared to bare magnesium. Polydopamine layers prepared with optimized coating procedure showed promising corrosion properties in Dulbecco's modified Eagle medium. In summary, polydopamine coatings offer a simple treatment for magnesium to improve the corrosion behavior and could further act as intermediate layer for further surface functionalization. PMID:26561489

  11. Corrosion considerations for thermochemical biomass liquefaction process systems in biofuel production

    DOE PAGES

    Brady, Michael P.; Keiser, James R.; Leonard, Donovan N.; Whitmer, Lysle; Thomson, Jeffery K.

    2014-11-11

    Thermochemical liquifaction processing of biomass to produce bio-derived fuels (e.g. gasoline, jet fuel, diesel, home heating oil, etc.) is of great recent interest as a renewable energy source. Approaches under investigation include direct liquefaction, hydrothermal liquefaction, hydropyrolysis, fast pyrolysis, etc. to produce energy dense liquids that can be utilized as produced or further processed to provide products of higher value. An issue with bio-oils is that they tend to contain significant concentrations of organic compounds, which make the bio-oil acidic and a potential source of corrosion issues in in transport, storage, and use. Efforts devoted to modified/further processing of bio-oilsmore » to make them less corrosive are currently being widely pursued. Another aspect that must also be addressed is potential corrosion issues in the bio-oil liquefaction process equipment itself. Depending on the specific process, bio-oil liquefaction production temperatures can reach up to 400-600 °C, and involve the presence of aggressive sulfur, and halide species from both the biomass used and/or process additives. Detailed knowledge of the corrosion resistance of candidate process equipment alloys in these bio-oil production environments is currently lacking. Lastly, this paper summarizes our recent, ongoing efforts to assess the extent to which corrosion of bio-oil process equipment may be an issue, with the ultimate goal of providing the basis to select the lowest cost alloy grades capable of providing the long-term corrosion resistance needed for future bio-oil production plants.« less

  12. Corrosion considerations for thermochemical biomass liquefaction process systems in biofuel production

    SciTech Connect

    Brady, Michael P.; Keiser, James R.; Leonard, Donovan N.; Whitmer, Lysle; Thomson, Jeffery K.

    2014-11-11

    Thermochemical liquifaction processing of biomass to produce bio-derived fuels (e.g. gasoline, jet fuel, diesel, home heating oil, etc.) is of great recent interest as a renewable energy source. Approaches under investigation include direct liquefaction, hydrothermal liquefaction, hydropyrolysis, fast pyrolysis, etc. to produce energy dense liquids that can be utilized as produced or further processed to provide products of higher value. An issue with bio-oils is that they tend to contain significant concentrations of organic compounds, which make the bio-oil acidic and a potential source of corrosion issues in in transport, storage, and use. Efforts devoted to modified/further processing of bio-oils to make them less corrosive are currently being widely pursued. Another aspect that must also be addressed is potential corrosion issues in the bio-oil liquefaction process equipment itself. Depending on the specific process, bio-oil liquefaction production temperatures can reach up to 400-600 °C, and involve the presence of aggressive sulfur, and halide species from both the biomass used and/or process additives. Detailed knowledge of the corrosion resistance of candidate process equipment alloys in these bio-oil production environments is currently lacking. Lastly, this paper summarizes our recent, ongoing efforts to assess the extent to which corrosion of bio-oil process equipment may be an issue, with the ultimate goal of providing the basis to select the lowest cost alloy grades capable of providing the long-term corrosion resistance needed for future bio-oil production plants.

  13. Process for producing a corrosion-resistant solid lubricant coating

    SciTech Connect

    Niederhaeuser, P.; Hintermann, H.E.; Maillat, M.

    1983-11-15

    A corrosion-resistant surface formed of a sulfide-forming metal, in particular nickel, is first subjected to an electric plasma in an atmosphere containing hydrogen sulfide to form an adherent sulfide on said surface. The sulfided surface is then exposed to simultaneous cathodic sputtering of at least one solid lubricant which is a chalcogen compound of layer structure, in particular MoS/sub 2/, and at least one hydrophobic solid polymer, in particular PTFE. The coating thus formed is a composite coating in which the particles of the chalcogen compound are coated by the polymer. When the surface of the part to be coated does not consist of a corrosion-resistant sulfide-forming metal, a layer of such a metal is first deposited by cathodic sputtering. The composite coating withstands a wet oxidizing atmosphere, contrary to a coating of MoS/sub 2/ alone, and the method is applicable to any mechanical part intended to rub on other surfaces, such as a watch balance wheel staff and ball or roller bearings.

  14. An energetic evaluation of dissolution corrosion capabilities of liquid metals on iron surface.

    PubMed

    Xu, Yichun; Song, Chi; Zhang, Yange; Liu, C S; Pan, B C; Wang, Zhiguang

    2014-08-21

    Using first principles calculations, dissolution corrosion of liquid metals on iron surfaces has been investigated by calculating adsorption energies of metal atoms in the liquid phase on the surface and escape energies of surface Fe atoms. The adsorption energies, characterizing the stability of the adsorbed atoms on the investigated surfaces, show that Bi is more stable than Pb and Au. The escape energies, representing the energy required for an Fe atom to escape from the surface, show that adsorbed Pb makes surface Fe atoms escape more easily than Bi and Au. The combination of adsorption energy and escape energy indicates that the corrosion capabilities of liquid metals decrease in the order Bi > Pb > Au. This is further proved by the investigation of surface properties, such as inter-layer distance, magnetic momentum and charge density difference. The results are consistent with experimental results that Fe can be corroded more severely in Bi than in Pb. In the case of liquid alloys, chemical proportions of compositions are incorporated to evaluate the corrosion capabilities of Pb-Bi eutectic (LBE) and Pb-Au eutectic (LGE). It is found that LBE has more severe corrosion capability than LGE. The energetic calculation is further developed in evaluating the effect of alloying elements in popular steels on the dissolution corrosion. The results indicate that Si, V, Nb and Mo may mitigate the dissolution corrosion of martensite steels in liquid Pb, Bi and Au.

  15. A new corrosion sensor to determine the start and development of embedded rebar corrosion process at coastal concrete.

    PubMed

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-09-30

    The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

  16. Microstructure and corrosion behavior of laser processed NiTi alloy.

    PubMed

    Marattukalam, Jithin J; Singh, Amit Kumar; Datta, Susmit; Das, Mitun; Balla, Vamsi Krishna; Bontha, Srikanth; Kalpathy, Sreeram K

    2015-12-01

    Laser Engineered Net Shaping (LENS™), a commercially available additive manufacturing technology, has been used to fabricate dense equiatomic NiTi alloy components. The primary aim of this work is to study the effect of laser power and scan speed on microstructure, phase constituents, hardness and corrosion behavior of laser processed NiTi alloy. The results showed retention of large amount of high-temperature austenite phase at room temperature due to high cooling rates associated with laser processing. The high amount of austenite in these samples increased the hardness. The grain size and corrosion resistance were found to increase with laser power. The surface energy of NiTi alloy, calculated using contact angles, decreased from 61 mN/m to 56 mN/m with increase in laser energy density from 20 J/mm(2) to 80 J/mm(2). The decrease in surface energy shifted the corrosion potentials to nobler direction and decreased the corrosion current. Under present experimental conditions the laser power found to have strong influence on microstructure, phase constituents and corrosion resistance of NiTi alloy.

  17. Influence of the casting processing route on the corrosion behavior of dental alloys.

    PubMed

    Galo, Rodrigo; Rocha, Luis Augusto; Faria, Adriana Claudia; Silveira, Renata Rodrigues; Ribeiro, Ricardo Faria; de Mattos, Maria da Gloria Chiarello

    2014-12-01

    Casting in the presence of oxygen may result in an improvement of the corrosion performance of most alloys. However, the effect of corrosion on the casting without oxygen for dental materials remains unknown. The aim of this study was to investigate the influence of the casting technique and atmosphere (argon or oxygen) on the corrosion behavior response of six different dental casting alloys. The corrosion behavior was evaluated by electrochemical measurements performed in artificial saliva for the different alloys cast in two different conditions: arc melting in argon and oxygen-gas flame centrifugal casting. A slight decrease in open-circuit potential for most alloys was observed during immersion, meaning that the corrosion tendency of the materials increases due to the contact with the solution. Exceptions were the Co-based alloys prepared by plasma, and the Co-Cr-Mo and Ni-Cr-4Ti alloys processed by oxidized flame, in which an increase in potential was observed. The amount of metallic ions released into the artificial saliva solution during immersion was similar for all specimens. Considering the pitting potential, a parameter of high importance when considering the fluctuating conditions of the oral environment, Co-based alloys show the best performance in comparison with the Ni-based alloys, independent of the processing route.

  18. Microstructure and corrosion behavior of laser processed NiTi alloy.

    PubMed

    Marattukalam, Jithin J; Singh, Amit Kumar; Datta, Susmit; Das, Mitun; Balla, Vamsi Krishna; Bontha, Srikanth; Kalpathy, Sreeram K

    2015-12-01

    Laser Engineered Net Shaping (LENS™), a commercially available additive manufacturing technology, has been used to fabricate dense equiatomic NiTi alloy components. The primary aim of this work is to study the effect of laser power and scan speed on microstructure, phase constituents, hardness and corrosion behavior of laser processed NiTi alloy. The results showed retention of large amount of high-temperature austenite phase at room temperature due to high cooling rates associated with laser processing. The high amount of austenite in these samples increased the hardness. The grain size and corrosion resistance were found to increase with laser power. The surface energy of NiTi alloy, calculated using contact angles, decreased from 61 mN/m to 56 mN/m with increase in laser energy density from 20 J/mm(2) to 80 J/mm(2). The decrease in surface energy shifted the corrosion potentials to nobler direction and decreased the corrosion current. Under present experimental conditions the laser power found to have strong influence on microstructure, phase constituents and corrosion resistance of NiTi alloy. PMID:26354269

  19. Microbiological and abiotic processes in modelling longer-term marine corrosion of steel.

    PubMed

    Melchers, Robert E

    2014-06-01

    Longer term exposure of mild steel in natural (biotic) waters progresses as a bimodal function of time, both for corrosion mass loss and for pit depth. Recent test results, however, found this also for immersion in clean fresh, almost pure and triply distilled waters. This shows chlorides or microbiological activity is not essential for the electrochemical processes producing bimodal behaviour. It is proposed that the first mode is aerobic corrosion that eventually produces a non-homogeneous corroded surface and rust coverage sufficient to allow formation of anoxic niches. Within these, aggressive autocatalytic reduction then occurs under anoxic abiotic conditions, caused by sulfide species originating from the MnS inclusions typical in steels. This is consistent with Wranglen's model for abiotic anoxic crevice and pitting corrosion without external aggressive ions. In biotic conditions, metabolites from anaerobic bacterial activity within and near the anoxic niches provides additional (sulfide) species to contribute to the severity of corrosion. Limited observational evidence that supports this hypothesis is given but further investigation is required to determine all contributor(s) to the cathodic current for the electrochemical reaction. The results are important for estimating the contribution of microbiological corrosion in infrastructure applications. PMID:24067447

  20. Microbiological and abiotic processes in modelling longer-term marine corrosion of steel.

    PubMed

    Melchers, Robert E

    2014-06-01

    Longer term exposure of mild steel in natural (biotic) waters progresses as a bimodal function of time, both for corrosion mass loss and for pit depth. Recent test results, however, found this also for immersion in clean fresh, almost pure and triply distilled waters. This shows chlorides or microbiological activity is not essential for the electrochemical processes producing bimodal behaviour. It is proposed that the first mode is aerobic corrosion that eventually produces a non-homogeneous corroded surface and rust coverage sufficient to allow formation of anoxic niches. Within these, aggressive autocatalytic reduction then occurs under anoxic abiotic conditions, caused by sulfide species originating from the MnS inclusions typical in steels. This is consistent with Wranglen's model for abiotic anoxic crevice and pitting corrosion without external aggressive ions. In biotic conditions, metabolites from anaerobic bacterial activity within and near the anoxic niches provides additional (sulfide) species to contribute to the severity of corrosion. Limited observational evidence that supports this hypothesis is given but further investigation is required to determine all contributor(s) to the cathodic current for the electrochemical reaction. The results are important for estimating the contribution of microbiological corrosion in infrastructure applications.

  1. Corrosion 99: Proceedings

    SciTech Connect

    1999-11-01

    This conference includes the following; Corrosion in Gas Treating; Advances in Scale and Deposit Control; Uses of Computers for Improved Corrosion Control; Erosion-Corrosion in Steam Generating Systems; Electrochemical Noise Measurements for Corrosion Evaluations; Materials Performance in Fossil Fuel Combustion and Conversion Systems; Corrosion in Super Critical Processes; Cathodic Protection of External Surfaces for Underground and Aboveground Storage Tanks; Microbiologically Influenced Corrosion; Advances in Materials for Oilfield Applications; Refining Industry Corrosion; Green Corrosion/Scale Inhibition Technologies; Managing Corrosion With Plastics; Corrosion Measurement Technology; Marine Corrosion; Improved Understanding and Mitigation of CO{sub 2} Corrosion; Thermal Spray Coatings for Corrosion Protection; Volatile Corrosion Inhibitors; Corrosion Testing in Concrete; Stress Corrosion Cracking: Field Laboratory Correlations; Materials Performance in Incineration and Waste Fuel Combustion Environments; Water Reuse in Industry; Corrosion Control and Prevention of Military and Aerospace Equipment; Corrosion in Nuclear Systems; Latest Developments in Aboveground Storage Tanks Corrosion Control, Monitoring and Evaluation Technology; Internal In-line Inspection of Pipelines and Evaluation of Results; New Developments in Cathodic Protection of Reinforcing Steels in Concrete; Cathodic Protection in Natural Waters; Corrosion in the Pulp and Paper Industry; Advanced Materials for High Temperature Service in Chemical Process Industry; Advances in Cooling Water Treatment; Materials, Fabrication, and Inspection Guidelines for Wet H{sub 2}S Service; Environmental Wear of Nonmetallics in Oilfield Service; and Corrosion and Scale Control in Low Pressure Boiler and Steam Systems in Buildings. Separate abstracts were prepared for most of the papers.

  2. Corrosion 99: Proceedings

    SciTech Connect

    Not Available

    1999-01-01

    This conference includes the following; Corrosion in Gas Treating; Advances in Scale and Deposit Control; Uses of Computers for Improved Corrosion Control; Erosion-Corrosion in Steam Generating Systems; Electrochemical Noise Measurements for Corrosion Evaluations; Materials Performance in Fossil Fuel Combustion and Conversion Systems; Corrosion in Super Critical Processes; Cathodic Protection of External Surfaces for Underground and Aboveground Storage Tanks; Microbiologically Influenced Corrosion; Advances in Materials for Oilfield Applications; Refining Industry Corrosion; Green Corrosion/Scale Inhibition Technologies; Managing Corrosion With Plastics; Corrosion Measurement Technology; Marine Corrosion; Improved Understanding and Mitigation of CO[sub 2] Corrosion; Thermal Spray Coatings for Corrosion Protection; Volatile Corrosion Inhibitors; Corrosion Testing in Concrete; Stress Corrosion Cracking: Field Laboratory Correlations; Materials Performance in Incineration and Waste Fuel Combustion Environments; Water Reuse in Industry; Corrosion Control and Prevention of Military and Aerospace Equipment; Corrosion in Nuclear Systems; Latest Developments in Aboveground Storage Tanks Corrosion Control, Monitoring and Evaluation Technology; Internal In-line Inspection of Pipelines and Evaluation of Results; New Developments in Cathodic Protection of Reinforcing Steels in Concrete; Cathodic Protection in Natural Waters; Corrosion in the Pulp and Paper Industry; Advanced Materials for High Temperature Service in Chemical Process Industry; Advances in Cooling Water Treatment; Materials, Fabrication, and Inspection Guidelines for Wet H[sub 2]S Service; Environmental Wear of Nonmetallics in Oilfield Service; and Corrosion and Scale Control in Low Pressure Boiler and Steam Systems in Buildings. Separate abstracts were prepared for most of the papers.

  3. Corrosion Resistance of Various High Chromium Alloys in Simulated Chemical Processing Nuclear Plant Waste Solutions

    SciTech Connect

    Anderson, P.A.; Agarwal, D.C.

    1997-12-31

    High chromium nickel alloys were tested at the Idaho Chemical Processing Plant (ICPP) to determine their corrosion performance in the high temperature aggressive chemical environments of liquid waste evaporators used in the chemical reprocessing of irradiated nuclear fuels. The results of these tests, which included a variety of base metal alloys I weld filler material combinations, are presented and discussed.

  4. The contribution of activated processes to Q. [stress corrosion cracking in seismic wave attenuation

    NASA Technical Reports Server (NTRS)

    Spetzler, H. A.; Getting, I. C.; Swanson, P. L.

    1980-01-01

    The possible role of activated processes in seismic attenuation is investigated. In this study, a solid is modeled by a parallel and series configuration of dashpots and springs. The contribution of stress and temperature activated processes to the long term dissipative behavior of this system is analyzed. Data from brittle rock deformation experiments suggest that one such process, stress corrosion cracking, may make a significant contribution to the attenuation factor, Q, especially for long period oscillations under significant tectonic stress.

  5. Energy release, beam attenuation radiation damage, gas production and accumulation of long-lived activity in Pb, Pb-Bi and Hg targets

    SciTech Connect

    Shubin, Yu.N.

    1996-06-01

    The calculation and analysis of the nuclei concentrations and long-lived residual radioactivity accumulated in Pb, Pb-Bi and Hg targets irradiated by 800 MeV, 30 mA proton beam have been performed. The dominating components to the total radioactivity of radionuclides resulting from fission and spallation reactions and radiative capture by both target nuclei and accumulated radioactive nuclei for various irradiation and cooling times were analyzed. The estimations of spectral component contributions of neutron and proton fluxes to the accumulated activity were carried out. The contributions of fission products to the targets activity and partial activities of main long-lived fission products to the targets activity and partial activities of main long-lived fission products were evaluated. The accumulation of Po isotopes due to reactions induced by secondary alpha-particles were found to be important for the Pb target as compared with two-step radiative capture. The production of Tritium in the targets and its contribution to the total targets activity was considered in detail. It is found that total activities of both targets are close to one another.

  6. Effect of natural and synthetic iron corrosion products on silicate glass alteration processes

    NASA Astrophysics Data System (ADS)

    Dillmann, Philippe; Gin, Stéphane; Neff, Delphine; Gentaz, Lucile; Rebiscoul, Diane

    2016-01-01

    Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influenced by near-field materials and environmental context. As previous studies have shown, the extent of glass alteration is strongly related to the presence of iron in the system, mainly provided by the steel overpack around surrounding the HLW glass package. A key to understanding what will happen to the glass-borne elements in the geological disposal lies in the relationship between the iron-bearing phases and the glass alteration products formed. In this study, we focus on the influence of the formation conditions (synthetized or in-situ) and the age of different iron corrosion products on SON68 glass alteration. Corrosion products obtained from archaeological iron artifacts are considered here to be true analogues of the corrosion products in a waste disposal system due to the similarities in formation conditions and physical properties. These representative corrosion products (RCP) are used in the experiment along with synthetized iron anoxic corrosion products and pristine metallic iron. The model-cracks of SON68 glass were altered in cell reactors, with one of the different iron-sources inserted in the crack each time. The study was successful in reproducing most of the processes observed in the long term archaeological system. Between the different systems, alteration variations were noted both in nature and intensity, confirming the influence of the iron-source on glass alteration. Results seem to point to a lesser effect of long term iron corrosion products (RCP) on the glass alteration than that of the more recent products (SCP), both in terms of general glass alteration and of iron transport.

  7. Corrosion protection

    DOEpatents

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  8. Correlation of Process Data and Electrochemical Noise to Assess Kraft Digester Corrosion: Spring Grove Experiment

    SciTech Connect

    Pawel, SJ

    2003-06-18

    Electrochemical noise (ECN) probes were deployed in a carbon steel continuous kraft digester at four locations and at one location in the bottom cone of the associated flash tank. The probes consisted of carbon steel electrodes, representing the vessel construction material, and 309LSi stainless steel overlay electrodes, representing the weld overlay repair in a portion of the vessel. Current and potential noise, the temperature at each probe location, and the value of about 32 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously for a period of almost one year. Historical vessel inspection data and post-test evaluation of the probe components were used to assess/compare ECN corrosion activity with physical changes in wall thickness and corrosion patterns on the digester shell. In addition, attempts were made to correlate ECN activity from each electrode type with process parameters. The results indicate the high general corrosion rates of steel observed just below the extraction screens--on the order of 35 mils/y for the past few years--accelerated further during the period of probe deployment. The maximum wastage of steel (normalized to one full year exposure) was about 85 mils/y at the ring 6N probe just below the extraction screens. Consistent with recent historical observations, the steel corrosion rate at the ring 6S probe--at the same elevation but directly across the digester from ring 6N--was significantly lower at about 50 mils/y. Just prior to probe deployment, the digester shell below the extraction screens was overlaid with 309LSi stainless steel, which was observed to be essentially immune to corrosion at this location. While the ECN probes detected differences in electrochemical behavior between steel probes and between 309LSi probes at rings 6N and 6S, there was only poor quantitative correlation of current sums with actual corrosion rates at these locations. A significant contribution of redox reactions on both steel

  9. Hydroxyl carboxylate based non-phosphorus corrosion inhibition process for reclaimed water pipeline and downstream recirculating cooling water system.

    PubMed

    Wang, Jun; Wang, Dong; Hou, Deyin

    2016-01-01

    A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies (PRWS) and in downstream recirculating cooling water systems (RCWS) using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors (e.g., gluconate, citrate, tartrate) and zinc sulfate heptahydrate, which provided Zn(2+) as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate (which could be utilized as a corrosion inhibitor) content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS. Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO4(3-) and Zn(2+) when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.

  10. Rapid assessment of anisotropic surface processes: experiments on the corrosion of Inconel 600

    NASA Astrophysics Data System (ADS)

    Schuh, Christopher A.; Anderson, Kelly; Orme, Christine

    2003-10-01

    We present a general experimental method for rapid characterization of surface processes on crystals of many orientations. By correlating maps of crystallographic orientation (obtained by electron backscatter diffraction methods) with those of surface topography (obtained by atomic force microscopy), we illustrate how a surface property can be elucidated on many off-principle crystal surfaces from a single polycrystalline specimen. For the corrosion of Inconel 600 in a dilute aqueous solution of HCl, we find that corrosion rates scale with the deviation angle of the surface normal from an ideal <1 1 1> direction. The use of atomic force microscopy can also provide mechanistic details about the surface process in question. For Inconel 600, we correlate the surface oxide morphology directly to the orientation of the underlying crystal.

  11. Corrosion Processes of the CANDU Steam Generator Materials in the Presence of Silicon Compounds

    SciTech Connect

    Lucan, Dumitra; Fulger, Manuela; Velciu, Lucian; Lucan, Georgiana; Jinescu, Gheorghita

    2006-07-01

    The feedwater that enters the steam generators (SG) under normal operating conditions is extremely pure but, however, it contains low levels (generally in the {mu}g/l concentration range) of impurities such as iron, chloride, sulphate, silicate, etc. When water is converted into steam and exits the steam generator, the non-volatile impurities are left behind. As a result of their concentration, the bulk steam generator water is considerably higher than the one in the feedwater. Nevertheless, the concentrations of corrosive impurities are in general sufficiently low so that the bulk water is not significantly aggressive towards steam generator materials. The impurities and corrosion products existing in the steam generator concentrate in the porous deposits on the steam generator tubesheet. The chemical reactions that take place between the components of concentrated solutions generate an aggressive environment. The presence of this environment and of the tubesheet crevices lead to localized corrosion and thus the same tubes cannot ensure the heat transfer between the fluids of the primary and secondary circuits. Thus, it becomes necessary the understanding of the corrosion process that develops into SG secondary side. The purpose of this paper is the assessment of corrosion behavior of the tubes materials (Incoloy-800) at the normal secondary circuit parameters (temperature = 2600 deg C, pressure = 5.1 MPa). The testing environment was demineralized water containing silicon compounds, at a pH=9.5 regulated with morpholine and cyclohexyl-amine (all volatile treatment - AVT). The paper presents the results of metallographic examinations as well as the results of electrochemical measurements. (authors)

  12. Real Time Corrosion Monitoring in Lead and Lead-Bismuth Systems

    SciTech Connect

    James F. Stubbins; Alan Bolind; Ziang Chen

    2010-02-25

    The objective of this research program is to develop a real-time, in situ corrosion monitoring technique for flowing liquid Pb and eutectic PbBi (LBE) systems in a temperature range of 400 to 650 C. These conditions are relevant to future liquid metal cooled fast reactor operating parameters. THis program was aligned with the Gen IV Reactor initiative to develp technologies to support the design and opertion of a Pb or LBE-cooled fast reactor. The ability to monitor corrosion for protection of structural components is a high priority issue for the safe and prolonged operation of advanced liquid metal fast reactor systems. In those systems, protective oxide layers are intentionally formed and maintained to limit corrosion rates during operation. This program developed a real time, in situ corrosion monitoring tecnique using impedance spectroscopy (IS) technology.

  13. Development, Processing, and Testing of High-Performance Corrosion-Resistant HVOF Coatings

    SciTech Connect

    Farmer, J; Wong, F; Haslam, J; Estill, J; Branagan, D; Yang, N; Blue, C

    2003-08-26

    New amorphous-metal and ceramic coatings applied by the high-velocity oxy-fuel (HVOF) process may reduce the waste package materials cost of the Yucca Mountain high-level nuclear waste repository by over $4 billion (cost reduction of 27 to 42%). Two critical requirements that have been determined from design analysis are protection in brines that may evolve from the evaporative concentration of pore waters and protection for waste package welds, thereby preventing exposure to environments that might cause stress corrosion cracking (SCC). Our efforts are directed towards producing and evaluating these high-performance coatings for the development of lower cost waste packages, and will leverage a cost-effective collaboration with DARPA for applications involving marine corrosion.

  14. Corrosion and degradation of test materials in the General Electric GEGAS 25 ton/day coal gasification process development unit

    SciTech Connect

    Yurkewycz, R.

    1985-01-31

    Alloys were evaluated in the GEGAS 25 ton/day coal gasification pilot plant operating at 300 psig (2.1 MPa gauge). The exposure period lasted for approximately 500 h under gasification conditions. Coupons were exposed in the gasifier (below the bottom grate and in the off-gas) and spray-quench vessel. Ferritic alloy 18Cr-2Mo was the best performing alloy (<20 mpy (0.5 mm/y)) in the air-superheated steam (temperature range: 500/sup 0/ to 1000/sup 0/F (260/sup 0/ to 538/sup 0/C)) environment in the ash pit below the grate assembly. Austenitic alloys Types 304 and 316 underwent stress-corrosion cracking. Irregular corrosion and pitting attack were the modes of corrosion for martenstic alloy Type 410, low-alloy steels 5Cr-0.5Mo and 2.25Cr-1Mo, and carbon steel A515. Their corrosion rates were >100 mpy (2.5 mm/y). In the gasifier off-gas test location, alloys Incoloy 800, Incoloy 825, and 20Cb-3 gave the best corrosion performance in the low-Btu product gas. Alloys 18-18-2, 18Cr-2Mo, and Type 321 experienced corrosion losses due to scaling; intergranular corrosion was experienced by Types 304 and 316. Operating temperatures ranged from 1000/sup 0/ to 1200/sup 0/F (538/sup 0/ to 649/sup 0/C). Process conditions were much milder for alloy coupons in the spray-quench vessel during 500 h exposure. High-alloy steels (18-18-2, 18Cr-2Mo, Types 304 and 316) experienced little corrosion at 350/sup 0/ to 400/sup 0/F (177/sup 0/ to 204/sup 0/C) in the vapor phase. The performances of carbon steel A515 and cast iron A278 were unacceptable since corrosion rates were >30 mpy (0.8 mm/y). 13 refs., 11 figs., 7 tabs.

  15. Corrosion prevention: Conversion coatings and coating processes. (Latest citations from the US Patent database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations of selected patents concerning conversion coatings and coating processes for the prevention of metal corrosion in various environments. Conversion coating patents for the application of phosphates and chromates to the surfaces of aluminum, zinc, ferrous metals, titanium, cadmium, iron, steels, and various alloys are presented. Topics include coating compositions, surface preparations and pretreatments prior to coating applications, post-treatment of coated metal surfaces, coating quality control, and sacrificial coatings for jet engines. Specific patents concerning protective coatings are excluded and covered in a separate bibliography. (Contains a minimum of 162 citations and includes a subject term index and title list.)

  16. Inspection indications, stress corrosion cracks and repair of process piping in nuclear materials production reactors

    SciTech Connect

    Louthan, M.R. Jr.; West, S.L.; Nelson, D.Z.

    1991-12-31

    Ultrasonic inspection of Schedule 40 Type 304 stainless steel piping in the process water system of the Savannah River Site reactors has provided indications of discontinuities in less than 10% of the weld heat affected zones. Pipe sections containing significant indications are replaced with Type 304L components. Post removal metallurgical evaluation showed that the indications resulted from stress corrosion cracking in weld heat-affected zones and that the overall weld quality was excellent. The evaluation also revealed weld fusion zone discontinuities such as incomplete penetration, incomplete fusion, inclusions, underfill at weld roots and hot cracks. Service induced extension of these discontinuities was generally not significant although stress corrosion cracking in one weld fusion zone was noted. One set of UT indications was caused by metallurgical discontinuities at the fusion boundary of an extra weld. This extra weld, not apparent on the outer pipe surface, was slightly overlapping and approximately parallel to the weld being inspected. This extra weld was made during a pipe repair, probably associated with initial construction processes. The two nearly parallel welds made accurate assessment of the UT signal difficult. The implications of these observations to the inspection and repair of process water systems of nuclear reactors is discussed.

  17. Inspection indications, stress corrosion cracks and repair of process piping in nuclear materials production reactors

    SciTech Connect

    Louthan, M.R. Jr.; West, S.L.; Nelson, D.Z.

    1991-01-01

    Ultrasonic inspection of Schedule 40 Type 304 stainless steel piping in the process water system of the Savannah River Site reactors has provided indications of discontinuities in less than 10% of the weld heat affected zones. Pipe sections containing significant indications are replaced with Type 304L components. Post removal metallurgical evaluation showed that the indications resulted from stress corrosion cracking in weld heat-affected zones and that the overall weld quality was excellent. The evaluation also revealed weld fusion zone discontinuities such as incomplete penetration, incomplete fusion, inclusions, underfill at weld roots and hot cracks. Service induced extension of these discontinuities was generally not significant although stress corrosion cracking in one weld fusion zone was noted. One set of UT indications was caused by metallurgical discontinuities at the fusion boundary of an extra weld. This extra weld, not apparent on the outer pipe surface, was slightly overlapping and approximately parallel to the weld being inspected. This extra weld was made during a pipe repair, probably associated with initial construction processes. The two nearly parallel welds made accurate assessment of the UT signal difficult. The implications of these observations to the inspection and repair of process water systems of nuclear reactors is discussed.

  18. Use of chlorine dioxide in a secondary recovery process to inhibit bacterial fouling and corrosion

    SciTech Connect

    Knickrehm, M.; Caballero, E.; Romualdo, P.; Sandidge, J.

    1987-01-01

    A major oil company operates a secondary recovery waterflood in Inglewood, California. The waterflood currently processes 250,000 bbls. per day of produced fluid. The major economic and operational problems associated with a secondary recovery waterflood are: 1) corrosion due to oxygen, carbon dioxide, hydrogen sulfide, and bacteria (sulfate reducers and slime biomass), 2) plugging from deposits due to salts, sulfides, and biofilms. These problems lead to deterioration of water handling equipment, injection lines (surface and subsurface), and decreased water quality resulting in the plugging of injection wells. During the last 8 years the operator has used varying mechanical and chemical technology to solve these problems. From 1978 to 1982 traditional chemical programs were in effect. Over this time period there was a continuing decline in water quality, and a substantial increase in chemical and operational costs. It was determined at that time that the major reason for this was due to microbiological activity. With this in mind, the operator proceeded to test the effects of using Aqueous Chlorine Dioxide in one portion of their water handling facilities. Due to the success of the program it was applied field wide. Presently, the primary problems associated with bacteria have been arrested. Solving one corrosion problem can lead to the onset of another. The operator is now in the process of making a concentrated effort to eliminate the other synergistically related corrosive and plugging agents (O/sub 2/, CO/sub 2/, H/sub 2/S). A field history of the problems, findings, and solutions, are discussed along with an overview of our present direction.

  19. Corrosion/96 conference papers

    SciTech Connect

    1996-07-01

    Topics covered by this conference include: cathodic protection in natural waters; cleaning and repassivation of building HVAC systems; worldwide opportunities in flue gas desulfurization; advancements in materials technology for use in oil and gas service; fossil fuel combustion and conversion; technology of corrosion inhibitors; computers in corrosion control--modeling and information processing; recent experiences and advances of austenitic alloys; managing corrosion with plastics; corrosion measurement technology; corrosion inhibitors for concrete; refining industry; advances in corrosion control for rail and tank trailer equipment; CO{sub 2} corrosion--mechanisms and control; microbiologically influenced corrosion; corrosion in nuclear systems; role of corrosion in boiler failures; effects of water reuse on monitoring and control technology in cooling water applications; methods and mechanisms of scale and deposit control; corrosion detection in petroleum production lines; underground corrosion control; environmental cracking--relating laboratory results and field behavior; corrosion control in reinforced concrete structures; corrosion and its control in aerospace and military hardware; injection and process addition facilities; progress reports on the results of reinspection of deaerators inspected or repaired per RP0590 criteria; near 100% volume solids coating technology and application methods; materials performance in high temperature environments containing halides; impact of toxicity studies on use of corrosion/scale inhibitors; mineral scale deposit control in oilfield related operations; corrosion in gas treating; marine corrosion; cold climate corrosion; corrosion in the pulp and paper industry; gaseous chlorine alternatives in cooling water systems; practical applications of ozone in recirculating cooling water systems; and water reuse in industry. Over 400 papers from this conference have been processed separately for inclusion on the data base.

  20. Corrosion investigation of multilayered ceramics and experimental nickel alloys in SCWO process environments

    SciTech Connect

    Garcia, K.M.; Mizia, R.

    1995-02-01

    A corrosion investigation was done at MODAR, Inc., using a supercritical water oxidation (SCWO) vessel reactor. Several types of multilayered ceramic rings and experimental nickel alloy coupons were exposed to a chlorinated cutting oil TrimSol, in the SCWO process. A corrosion casing was designed and mounted in the vessel reactor with precautions to minimize chances of degrading the integrity of the pressure vessel. Fifteen of the ceramic coated rings were stacked vertically in the casing at one time for each test. There was a total of 36 rings. The rings were in groupings of three rings that formed five sections. Each section saw a different SCWO environment, ranging from 650 to 300{degrees}C. The metal coupons were mounted on horizontal threaded holders welded to a vertical rod attached to the casing cover in order to hang down the middle of the casing. The experimental nickel alloys performed better than the baseline nickel alloys. A titania multilayered ceramic system sprayed onto a titanium ring remained intact after 120-180 hours of exposure. This is the longest time any coating system has withstood such an environment without significant loss.

  1. Effect of Dissolved Oxygen on Cu Corrosion in Single Wafer Cleaning Process

    NASA Astrophysics Data System (ADS)

    Imai, Masayoshi; Yamashita, Yukinari; Futatsuki, Takashi; Shiohara, Morio; Kondo, Seiichi; Saito, Shuichi

    2009-04-01

    We investigated Cu corrosion at the via bottom of multi-layered Cu interconnects that occurred after post-etching wet cleaning and caused via open failures. We found that oxygen was dissolved into de-ionized water (DIW) on the wafer edge from the air atmosphere during the rinse step after chemical cleaning and that Cu was oxidized due to the high oxidation-reduction potential (ORP) of the rinse DIW. To prevent Cu interconnects from being corroded, control of the dissolved oxygen and the ORP of the rinse DIW by decreasing the oxygen concentration of the atmosphere in the cleaning machine as well as by using H2 water is required. This will become indispensable in the cleaning process of the next generation Cu interconnects.

  2. The chemistry of sodium chloride involvement in processes related to hot corrosion. [in gas turbine engines

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.

    1979-01-01

    Thermodynamic and mass transport calculations, and laboratory experiments elucidating the behavior of sodium chloride in combustion environments, in the deposition process, and in reactions with certain oxides on the surfaces of superalloys are summarized. It was found that some of the ingested salt is separated out of the air stream by the compressor. However, sodium chloride does pass from the compressor to the combustor where numerous chemical reactions take place. Here some of the salt is vaporized to yield gaseous sodium chloride molecules. Hydrogen and oxygen atoms present in the combustion products react with some sodium chloride to yield other gaseous species such as sodium, and a fraction of the salt remains as particulates. Both the gas phase and condensed sodium chloride can lead to sodium sulfate formation by various routes, all of which involve reaction with sulfur oxides and oxygen. In addition to contributing to the formation of sodium sulfate, the sodium chloride can contribute to corrosion directly.

  3. Corrosion Behavior of Carbon Steel with Hmta Inhibitor in Pickling Process

    NASA Astrophysics Data System (ADS)

    Liu, D.; Huang, L. P.

    In this investigation, attempts have been made to study the inhibitive effect of hexamethylenetetramine (HMTA) on carbon steel in 10% HCl (mass%) by weight loss, potentiodynamic polarization, EIS, and AFM. Results indicate that inhibition efficiency (IE) of HMTA increases with the increase in pickling immersion time from 10 to 60 min, and IE also increases with the increase in temperature. At higher temperatures (80°C), the IE values are higher and almost independent of pickling time. HMTA can be adsorbed on the surface of metal and reduce the corrosion rate of metal. HMTA is a kind of mixed inhibitor and can retard both the anodic dissolution and cathodic hydrogen evolution reactions independently. IE increases with the concentration of HMTA. Electrochemistry measurement shows that adsorption follows the Langmuir isotherm and the value of free energies of adsorption (ΔGads) is < 0, so the adsorption process can occur automatically. AFM analyses show HMTA can affect the surface roughness and protect metal.

  4. One-step spray-coating process for the fabrication of colorful superhydrophobic coatings with excellent corrosion resistance.

    PubMed

    Li, Jian; Wu, Runni; Jing, Zhijiao; Yan, Long; Zha, Fei; Lei, Ziqiang

    2015-10-01

    A simple method was used to generate colorful hydrophobic stearate particles via chemical reactions between inorganic salts and sodium stearate. Colored self-cleaning superhydrophobic coatings were prepared through a facile one-step spray-coating process by spraying the stearate particle suspensions onto stainless steel substrates. Furthermore, the colorful superhydrophobic coating maintains excellent chemical stability under both harsh acidic and alkaline circumstances. After being immersed in a 3.5 wt % NaCl aqueous solution for 1 month, the as-prepared coatings remained superhydrophobic; however, they lost their self-cleaning property with a sliding angle of about 46 ± 3°. The corrosion behavior of the superhydrophobic coatings on the Al substrate was characterized by the polarization curve and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion test results indicated that the superhydrophobic coatings possessed excellent corrosion resistance, which could supply efficient and long-term preservation for the bare Al substrate.

  5. Effect of additive on electrochemical corrosion properties of plasma electrolytic oxidation coatings formed on CP Ti under different processing frequency

    NASA Astrophysics Data System (ADS)

    Babaei, Mahdi; Dehghanian, Changiz; Vanaki, Mojtaba

    2015-12-01

    The plasma electrolytic oxidation (PEO) coating containing zirconium oxide was fabricated on CP Ti at different processing frequencies viz., 100 Hz and 1000 Hz in a (Na2ZrO3, Na2SiO3)-additive containing NaH2PO4-based solution, and long-term electrochemical corrosion behavior of the coatings was studied using electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Electrochemical degradation behavior of two-layered coatings formed at different frequencies was turned out to be governed by concentration of electrolyte additive. With increasing additive concentration, the coating obtained at frequency of 1000 Hz exhibited enhanced corrosion resistance. However, corrosion resistance of the coating prepared at 100 Hz was found to decrease with increased additive, which was attributed to intensified microdischarges damaging the protective effect of inner layer. Nevertheless, the electrolyte additive was found to mitigate the long-term degradation of the coatings to a significant extent.

  6. Aircraft Materials, Processes, Cleaning and Corrosion Control (Course Outline), Aviation Mechanics 1 (Power and Frame): 9073.01.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    This document presents an outline for a 135-hour course designed to familiarize the beginning student with the basic concepts common to aircraft materials and processes, together with the requirements of proper cleaning and corrosion control as outlined by the Federal Aviation Agency. The aviation airframe and powerplant maintenance technician is…

  7. A process for the production of a scale-proof and corrosion-resistant coating on graphite and carbon bodies

    NASA Technical Reports Server (NTRS)

    Fitzer, E.

    1981-01-01

    A process for the production of a corrosion resistant coating on graphite and carbon bodies is described. The carbon or graphite body is coated or impregnated with titanium silicide under the addition of a metal containing wetting agent in a nitrogen free atmosphere, so that a tight coating is formed.

  8. Impact of the chemicals, essential for the purification process of strict Fe-hydrogenase, on the corrosion of mild steel.

    PubMed

    Rouvre, Ingrid; Gauquelin, Charles; Meynial-Salles, Isabelle; Basseguy, Régine

    2016-06-01

    The influence of additional chemical molecules, necessary for the purification process of [Fe]-hydrogenase from Clostridium acetobutylicum, was studied on the anaerobic corrosion of mild steel. At the end of the purification process, the pure [Fe-Fe]-hydrogenase was recovered in a Tris-HCl medium containing three other chemicals at low concentration: DTT, dithionite and desthiobiotin. Firstly, mild steel coupons were exposed in parallel to a 0.1 M pH7 Tris-HCl medium with or without pure hydrogenase. The results showed that hydrogenase and the additional molecules were in competition, and the electrochemical response could not be attributed solely to hydrogenase. Then, solutions with additional chemicals of different compositions were studied electrochemically. DTT polluted the electrochemical signal by increasing the Eoc by 35 mV 24 h after the injection of 300 μL of control solutions with DTT, whereas it drastically decreased the corrosion rate by increasing the charge transfer resistance (Rct 10 times the initial value). Thus, DTT was shown to have a strong antagonistic effect on corrosion and was removed from the purification process. An optimal composition of the medium was selected (0.5 mM dithionite, 7.5 mM desthiobiotin) that simultaneously allowed a high activity of hydrogenase and a lower impact on the electrochemical response for corrosion tests.

  9. Review of state-of-the art of solar collector corrosion processes. Task 1 of solar collector studies for solar heating and cooling applications

    NASA Astrophysics Data System (ADS)

    Clifford, J. E.; Diegle, R. B.

    1980-04-01

    The state of the art of solar collector corrosion processes is reviewed, and Task 1 of a current research program on use of aqueous heat transfer fluids for solar heating and cooling is summarized. The review of available published literature indicated that lack of quantitative information exists relative to collector corrosion at the present time, particularly for the higher temperature applications of solar heating and cooling compared to domestic water heating. Solar collector systems are reviewed from the corrosion/service life viewpoint, with emphasis on various applications, collector design, heat transfer fluids, and freeze protection methods. Available information (mostly qualitative) on collector corrosion technology is reviewed to indicate potential corrosion problem areas and corrosion prevention practices.

  10. Cracking process of Fe-26Cr-1Mo during low cycle corrosion fatigue

    SciTech Connect

    Wang, J.Q.; Li, J.; Wang, Z.F.; Zhu, Z.Y.; Ke, W. . Corrosion Science Lab.); Zang, Q.S.; Wang, Z.G. . State Key Lab. for Fatigue and Fracture of Materials)

    1994-12-01

    The corrosion fatigue (CF) life has been divided classically into the initiation'' and propagation'' periods. Usually, the crack initiation process dominates the component lifetime under the low cycle CF condition because the crack propagates rapidly one initiated. Despite much work done on the research of the CF crack initiation mechanisms, however, a full understanding of crack initiation is still lacking. There are some limitations in explaining the CF crack initiation in an aqueous solution using the above four mechanisms individually. And, it is difficult to conduct experiments in which one mechanism along can be examined. Although CF is complicated, it is possible to reproduce a specific experiment condition which will have the dominant factor affecting the CF crack initiation. Once the cracks initiate on the smooth metal surface, their coalescence, micropropagation and macropropagation will take place successively. The initiated cracks propagate first in the range of several grains, and the behavior of the microcrack propagation is different from that of macrocrack propagation. For Fe-26Cr-1Mo ferritic stainless steel, the fundamental research work of straining electrode has been done by many investigators, but the observation of the material surface at different deformation processes has not been reported. In the present study, the detailed observation of the cracking process of the material has been carried out in low cycle CF.

  11. Monitoring of microbially mediated corrosion and scaling processes using redox potential measurements.

    PubMed

    Opel, Oliver; Eggerichs, Tanja; Otte, Tobias; Ruck, Wolfgang K L

    2014-06-01

    The use of redox potential measurements for corrosion and scaling monitoring, including microbially mediated processes, is demonstrated. As a case study, monitoring data from 10years of operation of an aquifer thermal energy storage (ATES) site located in Berlin, Germany, were examined. (Fe(2+))-activities as well as [Fe(3+)]-build up rates were calculated from redox potential, pH, conductivity, temperature and dissolved oxygen measurements. Calculations are based on assuming (Fe(3+))-activity being controlled by Fe(OH)3-solubility, the primary iron(III)-precipitate. This approach was tested using a simple log-linear model including dissolved oxygen besides major Fe(2+)-ligands. Measured redox potential values in groundwater used for thermal storage are met within ±8mV. In other systems comprising natural groundwater and in heating and cooling systems in buildings, quantitatively interpretable values are obtained also. It was possible to calculate particulate [Fe(3+)]-loads in the storage fluids in the order of 2μM and correlate a decrease in filter lifetimes to [Fe(3+)]-build up rates, although observations show clear signs of microbially mediated scaling processes involving iron and sulphur cycling.

  12. The corrosion process of sterling silver exposed to a Na2S solution: monitoring and characterizing the complex surface evolution using a multi-analytical approach

    NASA Astrophysics Data System (ADS)

    Schalm, Olivier; Crabbé, Amandine; Storme, Patrick; Wiesinger, Rita; Gambirasi, Arianna; Grieten, Eva; Tack, Pieter; Bauters, Stephen; Kleber, Christoph; Favaro, Monica; Schryvers, Dominique; Vincze, Laszlo; Terryn, Herman; Patelli, Alessandro

    2016-10-01

    Many historical `silver' objects are composed of sterling silver, a silver alloy containing small amounts of copper. Besides the dramatic impact of copper on the corrosion process, the chemical composition of the corrosion layer evolves continuously. The evolution of the surface during the exposure to a Na2S solution was monitored by means of visual observation at macroscopic level, chemical analysis at microscopic level and analysis at the nanoscopic level. The corrosion process starts with the preferential oxidation of copper, forming mixtures of oxides and sulphides while voids are being created beneath the corrosion layer. Only at a later stage, the silver below the corrosion layer is consumed. This results in the formation of jalpaite and at a later stage of acanthite. The acanthite is found inside the corrosion layer at the boundaries of jalpaite grains and as individual grains between the jalpaite grains but also as a thin film on top of the corrosion layer. The corrosion process could be described as a sequence of 5 subsequent surface states with transitions between these states.

  13. Test Plan: Sludge Treatment Project Corrosion Process Chemistry Follow-on Testing

    SciTech Connect

    Delegard, Calvin H.; Schmidt, Andrew J.; Poloski, Adam P.

    2007-08-17

    This test plan was prepared by the Pacific Northwest National Laboratory (PNNL) under contract with Fluor Hanford (FH). The test plan describes the scope and conditions to be used to perform laboratory-scale testing of the Sludge Treatment Project (STP) hydrothermal treatment of K Basin sludge. The STP, managed for the U. S. Department of Energy (DOE) by FH, was created to design and operate a process to eliminate uranium metal from the sludge prior to packaging for Waste Isolation Pilot Plant (WIPP) by using high temperature liquid water to accelerate the reaction, produce uranium dioxide from the uranium metal, and safely discharge the hydrogen. The proposed testing builds on the approach and laboratory test findings for both K Basin sludge and simulated sludge garnered during prior testing from September 2006 to March 2007. The outlined testing in this plan is designed to yield further understanding of the nature of the chemical reactions, the effects of compositional and process variations and the effectiveness of various strategies to mitigate the observed high shear strength phenomenon observed during the prior testing. These tests are designed to provide process validation and refinement vs. process development and design input. The expected outcome is to establish a level of understanding of the chemistry such that successful operating strategies and parameters can be implemented within the confines of the existing STP corrosion vessel design. In July 2007, the DOE provided direction to FH regarding significant changes to the scope of the overall STP. As a result of the changes, FH directed PNNL to stop work on most of the planned activities covered in this test plan. Therefore, it is unlikely the testing described here will be performed. However, to preserve the test strategy and details developed to date, the test plan has been published.

  14. The effect of various deformation processes on the corrosion behavior of casing and tubing carbon steels in sweet environment

    NASA Astrophysics Data System (ADS)

    Elramady, Alyaa Gamal

    The aim of this research project is to correlate the plastic deformation and mechanical instability of casing steel materials with corrosion behavior and surface change, in order to identify a tolerable degree of deformation for casing steel materials. While the corrosion of pipeline and casing steels has been investigated extensively, corrosion of these steels in sweet environments with respect to plastic deformation due to bending, rolling, autofrettage, or handling needs more investigation. Downhole tubular expansion of pipes (casings) is becoming standard practice in the petroleum industry to repair damaged casings, shutdown perforations, and ultimately achieve mono-diameter wells. Tubular expansion is a cold-drawing metal forming process, which consists of running conical mandrels through casings either mechanically using a piston or hydraulically by applying a back pressure. This mechanism subjects the pipes to large radial plastic deformations of up to 30 pct. of the inner diameter. It is known that cold-working is a way of strengthening materials such as low carbon steel, but given that this material will be subjected to corrosive environments, susceptibility to stress corrosion cracking (SCC) should be investigated. This research studies the effect of cold-work, in the form of cold-rolling and cold-expansion, on the surface behavior of API 5CT steels when it is exposed to a CO2-containing environment. Cold-work has a pronounced influence on the corrosion behavior of both API 5CT K55 and P110 grade steels. The lowest strength grade steel, API 5CT K55, performed poorly in a corrosive environment in the slow strain rate test. The ductile material exhibited the highest loss in strength and highest susceptibility to stress corrosion cracking in a CO 2-containing environment. The loss in strength declined with cold-rolling, which can be ascribed to the surface compressive stresses induced by cold-work. On the other hand, API 5CT P110 grade steels showed higher

  15. Correlation of Process Data and Electrocheical Noise to Assess Kraft Digester Corrosion: Second Year at Spring Grove

    SciTech Connect

    Pawel, SJ

    2004-04-27

    Electrochemical noise (EN) probes were deployed in the carbon steel continuous kraft digester at Spring Grove at four locations and at one location in the bottom cone of the associated flash tank for a second consecutive year of a corrosion study. The probes contained dual electrodes of 309LSi stainless steel overlay--representing a field repair material applied to a portion of the vessel--and dual electrodes of 312 stainless steel overlay. Current and potential noise, the temperature at each probe location, and the value of 23 process parameters (flow rates, liquor chemistry, etc.) were again monitored continuously for a period of almost one year. Historical vessel inspection data and post-test evaluation of the probe components were used to assess/compare EN corrosion activity with physical changes in wall thickness and corrosion patterns on the digester shell. In addition, attempts were made to correlate EN activity from each electrode type with process parameters. The results indicate the corrosion conditions aggressive to mild steel persist within the digester, as post-test inspection of the vessel revealed localized corrosion of mild steel in locations previously free of attack. Further, there was evidence that the depth of localized attack of exposed steel had increased in some locations. Nevertheless, the stainless steel overlay in the digester was essentially immune to corrosion, as evidenced by retained surface relief and heat tint associated with the original deposition process. The 309LSi electrodes also appeared visually pristine, and post-exposure metallographic examination of the 309LSi electrode materials revealed no attack. The 312 electrode materials were similar in appearance, but exhibited very minor interdendritic attack over the exposed surface. The silver electrodes in the probes were consumed (to Ag{sub 2}S) to variable degree over the course of the exposure indicating a useful life of not more than a year in digester service in this vessel

  16. Fabrication of near-field optical apertures in aluminium by a highly selective corrosion process in the evanescent field.

    PubMed

    Haefliger, D; Stemmer, A

    2003-03-01

    A simple, one-step process to fabricate high-quality apertures for scanning near-field optical microscope probes based on aluminium-coated silicon nitride cantilevers is presented. A thin evanescent optical field at a glass-water interface was used to heat the aluminium at the tip apex due to light absorption. The heat induced a breakdown of the passivating oxide layer and local corrosion of the metal, which selectively exposed the front-most part of the probe tip from the aluminium. Apertures with a protruding silicon nitride tip up to 72 nm in height were fabricated. The height of the protrusion was controlled by the extent of the evanescent field, whereas the diameter depended on the geometry of the probe substrate. The corrosion process proved to be self-terminating, yielding highly reproducible tip heights. Near-field optical resolution in a transmission mode of 85 nm was demonstrated.

  17. Temperature effect on the corrosion mechanism of austenitic and martensitic steels in lead-bismuth

    NASA Astrophysics Data System (ADS)

    Benamati, G.; Fazio, C.; Piankova, H.; Rusanov, A.

    2002-02-01

    Compatibility tests on the austenitic AISI 316L and the martensitic MANET II steels in stagnant PbBi were performed at 573, 673 and 823 K with exposures up to 5000 h. The change of the corrosion mechanism with increasing temperature has been evaluated. The results showed that at 573 and 673 K a thin oxide layer growth on the surface of both steels. By increasing the temperature to 823 K both types of steels were attacked by the liquid metal and dissolution of the steel alloying elements has been observed. The herein-reported experimental activities were performed in collaboration with the IPPE of Obninsk, where preliminary dynamic tests were performed in the experimental facility CU-2. The Russian ferritic-martensitic steel EP823 has been exposed to flowing PbBi at 623, 723 and 823 K for 700 h. After 700 h of testing, the surface of the EP823 samples showed for the three temperatures a compact oxide layer.

  18. The effect of microarc oxidation and excimer laser processing on the microstructure and corrosion resistance of Zr-1Nb alloy

    NASA Astrophysics Data System (ADS)

    Yang, Jiaoxi; Wang, Xin; Wen, Qiang; Wang, Xibing; Wang, Rongshan; Zhang, Yanwei; Xue, Wenbin

    2015-12-01

    The main purpose of this research was to investigate the effect of microarc oxidation (MAO) and excimer laser processing on the corrosion resistance of Zr-1Nb alloy in service environment. The pre-oxide film was fabricated on the surface of Zr-1Nb cladding tubes by MAO processing, and then subjected to KrF excimer laser irradiation. The surface morphology of the pre-oxide film was observed using a scanning electron microscope; phase compositions and quantities were determined using an X-ray diffraction; surface roughness was determined using a profilometer; and thermal expansion coefficient was measured using a dilatometer. Autoclave experiments were conducted for 94 days in an aqueous condition of 360 °C under 18.6 MPa in 0.01 mol/L LiOH solutions. The results showed that MAO + laser treatment resulted in a significant increase in the corrosion resistance of Zr-1Nb cladding tubes at high temperatures, because laser melting and etching could lead to a reduction in surface roughness and an increase in compactness of the pre-oxide film, and laser processing could promote the transformation of m-ZrO2 phase to t-ZrO2 phase. The best corrosion resistance was obtained when the pulse energy was 500 mJ, scanning speed was 0.13 mm/s, and pulse number was 2400.

  19. Modeling of concrete cracking due to corrosion process of reinforcement bars

    SciTech Connect

    Bossio, Antonio; Monetta, Tullio; Bellucci, Francesco; Lignola, Gian Piero; Prota, Andrea

    2015-05-15

    The reinforcement corrosion in Reinforced Concrete (RC) is a major reason of degradation for structures and infrastructures throughout the world leading to their premature deterioration before design life was attained. The effects of corrosion of reinforcement are: (i) the reduction of the cross section of the bars, and (ii) the development of corrosion products leading to the appearance of cracks in the concrete cover and subsequent cover spalling. Due to their intrinsic complex nature, these issues require an interdisciplinary approach involving both material science and structural design knowledge also in terms on International and National codes that implemented the concept of durability and service life of structures. In this paper preliminary FEM analyses were performed in order to simulate pitting corrosion or general corrosion aimed to demonstrate the possibility to extend the results obtained for a cylindrical specimen, reinforced by a single bar, to more complex RC members in terms of geometry and reinforcement. Furthermore, a mechanical analytical model to evaluate the stresses in the concrete surrounding the reinforcement bars is proposed. In addition, a sophisticated model is presented to evaluate the non-linear development of stresses inside concrete and crack propagation when reinforcement bars start to corrode. The relationships between the cracking development (mechanical) and the reduction of the steel section (electrochemical) are provided. Finally, numerical findings reported in this paper were compared to experimental results available in the literature and satisfactory agreement was found.

  20. Review of state-of-the-art of solar collector corrosion processes. Task 1 of solar collector studies for solar heating and cooling applications. Final technical progress report

    SciTech Connect

    Clifford, J E; Diegle, R B

    1980-04-11

    The state-of-the-art of solar collector corrosion processes is reviewed, and Task 1 of a current research program on use of aqueous heat transfer fluids for solar heating and cooling is summarized. The review of available published literature has indicated that lack of quantitative information exists relative to collector corrosion at the present time, particularly for the higher temperature applications of solar heating and cooling compared to domestic water heating. Solar collector systems are reviewed from the corrosion/service life viewpoint, with emphasis on various applications, collector design, heat transfer fluids, and freeze protection methods. Available information (mostly qualitative) on collector corrosion technology is reviewed to indicate potential corrosion problem areas and corrosion prevention practices. Sources of limited quantitative data that are reviewed are current solar applications, research programs on collector corrosion, and pertinent experience in related applications of automotive cooling and non-solar heating and cooling. A data bank was developed to catalog corrosion information. Appendix A of this report is a bibliography of the data bank, with abstracts reproduced from presently available literature accessions (about 220). This report is presented as a descriptive summary of information that is contained in the data bank.

  1. Chem I Supplement: Corrosion: A Waste of Energy.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 1979

    1979-01-01

    This article, intended for secondary school chemistry students, discusses the corrosion of metals. The discussion includes: (1) thermodynamic aspects of corrosion; (2) electrochemical aspects of corrosion; and (3) inhibition of corrosion processes. (HM)

  2. Corrosion resistance of metals in the process fluids of photographic film manufacturing plants

    SciTech Connect

    Khar'yu, N.A.; Tuktamysheva, N.V.; Garifzyanova, N.V.; Belyaeva, N.V.

    1983-02-01

    With the goal of choosing corrosion-resistant materials the corrosion resistance of a number of nickel steels in a mixture of acetone and ethanol (2:1) and diazo coating was determined. The low-alloyed steels 08Kh22N6T (EP-53), 07Khl6N6 (EP-288) and Khl5N7YuM2 (EP-35) are characterized by high corrosion resistance and can be recommended instead of the high-alloyed, expensive and difficult to obtain steels 08Khl8N10T and 10Khl7N13M2T as construction materials for manfacture of equipment to be used in the regeneration of wastes of diazotype photographic materials.

  3. Behavior of steels in flowing liquid PbBi eutectic alloy at 420-600 °C after 4000-7200 h

    NASA Astrophysics Data System (ADS)

    Müller, G.; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V.

    2004-11-01

    This paper presents the results of steel exposure up to 7200 h in flowing LBE at elevated temperatures and is a follow-up paper of that with results of an exposure of up to 2000 h. The examined AISI 316 L, 1.4970 austenitic and MANET 10Cr martensitic steels are suitable as a structural material in LBE (liquid eutectic Pb 45Bi 55) up to 550 °C, if 10 -6 wt% of oxygen is dissolved in the LBE. The martensitic steel develops a thick magnetite and spinel layer while the austenites have thin spinel surface layers at 420 °C and thick oxide scales like the martensitic steel at 550 °C. The oxide scales protect the steels from dissolution attack by LBE during the whole test period of 7200 h. Oxide scales that spall off are replaced by new protective ones. At 600 °C severe attack occurs already after 2000 and 4000 h of exposure. Steels with 8-15 wt% Al alloyed into the surface suffer no corrosion attack at all experimental temperatures and exposure times.

  4. Evolution of the corrosion process of AA 2024-T3 in an alkaline NaCl solution with sodium dodecylbenzenesulfonate and lanthanum chloride inhibitors

    NASA Astrophysics Data System (ADS)

    Zhou, Biner; Wang, Yishan; Zuo, Yu

    2015-12-01

    The evolution of the corrosion process of AA 2024-T3 in 0.58 g L-1 NaCl solution (pH 10) with sodium dodecylbenzenesulfonate (SDBS) and lanthanum chloride inhibitors was studied with electrochemical and surface analysis methods. With the addition of the compounded LaCl3 and SDBS inhibitors, in the early stage the polarization behavior of AA 2024-T3 changed from active corrosion to passivation, and both the general corrosion and pitting corrosion were inhibited. However, with the immersion time extended, the passive behavior gradually disappeared and pitting happened at the Cu-rich phases. After 24 h immersion, the compounded inhibitors still showed good inhibition for general corrosion, but the polarization curve again presented the characteristic similar to active polarization. The compounded inhibitors also inhibited the pitting corrosion to some extent. The acting mechanism of the inhibitors SDBS and La3Cl on the corrosion process of AA 2024-T3 in the test solution was discussed.

  5. The effect of porous coating processing on the corrosion behavior of cast Co-Cr-Mo surgical implant alloys.

    PubMed

    Jacobs, J J; Latanision, R M; Rose, R M; Veeck, S J

    1990-11-01

    The manufacture of porous coated cobalt-based surgical implant alloys requires sintering--a high temperature process above the incipient melting temperature of this alloy system. The metallurgical changes produced by the high temperature sinter cycle consist of dissolution of interdendritic carbides, massive precipitation of lamellar carbide eutectic phases at grain boundaries, localized porosity from incipient melting that is not completely eliminated by subsequent hot isostatic pressing, and grain growth in fine-grained materials. These microstructural changes, which are known to affect the mechanical properties, do not affect the static in vitro localized and generalized corrosion behavior of the bulk material as determined by anodic polarization measurements in a buffered saline environment and direct examination by scanning electron and optical microscopy. Additionally, cast Co-Cr-Mo surgical implant alloys are found to be immune to crevice corrosion (in the absence of mechanical fretting) in the saline environment studied. The hysteretic component of the anodic polarization curve is not due to crevice corrosion; rather, as suggested by the electrochemical tests and Auger spectroscopy, the hysteresis is due to redox reactions in the chromium-rich surface layer. PMID:2213344

  6. Corrosion resistance and long-term durability of super-hydrophobic nickel film prepared by electrodeposition process

    NASA Astrophysics Data System (ADS)

    Khorsand, S.; Raeissi, K.; Ashrafizadeh, F.

    2014-06-01

    A super-hydrophobic nickel film with micro-nano structure was successfully fabricated by electrodeposition process. By controlling electrodeposition parameters and considering different storage times for the coatings in air, various nickel films with different wettability were fabricated. Surface morphology of nickel films was examined by means of scanning electron microscopy (SEM). The results showed that the micro-nano nickel film was well-crystallized and exhibited pine cone-like microstructure with nano-cone arrays randomly dispersed on each micro-protrusion. The wettability of the micro-nano nickel film varied from super-hydrophilicity (water contact angle 5.3°) to super-hydrophobicity (water contact angle 155.7°) by exposing the surface in air at room temperature. The corrosion resistance of the super-hydrophobic film was estimated by electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The potentiodynamic curves revealed that the corrosion rate of superhydrophobic surface was only 0.16% of the bare copper substrate. Moreover, EIS measurements and appropriate equivalent circuit models revealed that the corrosion resistance of nickel films considerably improved with an increase in the hydrophobicity. The superhydrophobic surface also exhibited an excellent long-term durability in neutral 3.5 wt.% NaCl solution.

  7. Intergranular stress corrosion cracking: A rationalization of apparent differences among stress corrosion cracking tendencies for sensitized regions in the process water piping and in the tanks of SRS reactors

    SciTech Connect

    Louthan, M.R.

    1990-09-28

    The frequency of stress corrosion cracking in the near weld regions of the SRS reactor tank walls is apparently lower than the cracking frequency near the pipe-to-pipe welds in the primary cooling water system. The difference in cracking tendency can be attributed to differences in the welding processes, fabrication schedules, near weld residual stresses, exposure conditions and other system variables. This memorandum discusses the technical issues that may account the differences in cracking tendencies based on a review of the fabrication and operating histories of the reactor systems and the accepted understanding of factors that control stress corrosion cracking in austenitic stainless steels.

  8. SRB seawater corrosion project

    NASA Technical Reports Server (NTRS)

    Bozack, M. J.

    1991-01-01

    The corrosion behavior of 2219 aluminum when exposed to seawater was characterized. Controlled corrosion experiments at three different temperatures (30, 60 and 100 C) and two different environments (seawater and 3.5 percent salt solution) were designed to elucidate the initial stages in the corrosion process. It was found that 2219 aluminum is an active catalytic surface for growth of Al2O3, NaCl, and MgO. Formation of Al2O3 is favored at lower temperatures, while MgO is favored at higher temperatures. Visible corrosion products are formed within 30 minutes after seawater exposure. Corrosion characteristics in 3.5 percent salt solution are different than corrosion in seawater. Techniques utilized were: (1) scanning electron microscopy, (2) energy dispersive x-ray spectroscopy, and (3) Auger electron spectroscopy.

  9. Monitoring the Corrosion Process of Reinforced Concrete Using BOTDA and FBG Sensors

    PubMed Central

    Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

    2015-01-01

    Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions. PMID:25884790

  10. Microbiologically-influenced corrosion damage in a water coolant header for remote process equipment

    SciTech Connect

    Jenkins, C.F.

    1995-10-01

    Stainless steel water piping, used to supply coolant for remote chemical separations equipment, developed several leaks during low-flow conditions resulting from an extended interruption of operations. All the leaks occurred at welds in the bottom zone of the pipe, which was blanketed with silt deposits from the unfiltered well water used for cooling. Ultrasonic, radiographic, and metallographic examinations of the leak sites revealed worm-hole pitting adjacent to the welds. Seepage at the penetrations was strongly acidic and resulted in corrosion on the external pipe surfaces beneath brown crusty deposits which had developed. Analyses of the water and deposits suggested a strong propensity toward microbiologically-influenced corrosion (MIC) and fouling.

  11. Monitoring the corrosion process of reinforced concrete using BOTDA and FBG sensors.

    PubMed

    Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

    2015-04-15

    Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions.

  12. The chemistry of sodium chloride involvement in processes related to hot corrosion

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.

    1979-01-01

    Sodium chloride is one of the primary contaminants that enter gas turbine engines and contribute, either directly or indirectly, to the hot corrosion degradation of hot-gas-path components. The paper surveys the results of laboratory experiments along with thermodynamic and mass transport calculations, intended for elucidating the behavior of sodium chloride in combustion environments. It is shown that besides being a source of sodium for the formation of corrosive liquid Na2SO4, the NaCl itself contributes in other indirect ways to the material degradation associated with the high-temperature environmental attack. In addition, the experimental results lend credence to the conceptual scheme presented schematically (behavior of NaCl in a turbine engine combustion gas environment) and resolve conflicting aspects of relevant NaCl misconceptions.

  13. Ancient coins: cluster analysis applied to find a correlation between corrosion process and burial soil characteristics

    PubMed Central

    2012-01-01

    Although it is well known that any material degrades faster when exposed to an aggressive environment as well as that "aggressive" cannot be univocally defined as depending also on the chemical-physical characteristics of material, few researches on the identification of the most significant parameters influencing the corrosion of metallic object are available. A series of ancient coins, coming from the archaeological excavation of Palazzo Valentini (Rome) were collected together with soils, both near and far from them, and then analysed using different analytical techniques looking for a correlation between the corrosion products covering the coins and the chemical-physical soil characteristics. The content of soluble salts in the water-bearing stratum and surfacing in the archaeological site, was also measured. The obtained results stress the influence of alkaline soils on formation of patina. Cerussite, probably due to the circulation of water in layers rich in marble and plaster fragments, was the main corrosion product identified by X-ray Diffraction (XRD). Copper, lead and vanadium were found in soil surrounding coins. By measuring conductivity, pH and soluble salts content of the washing solutions from both coins and soils, we could easily separate coins coming from different stratigraphic units of the site. Data were treated by cluster and multivariate analysis, revealing a correlation between part of the coins and the nearby soil samples. PMID:22594444

  14. Copper corrosion in potable water systems: Impacts of natural organic matter and water treatment processes

    SciTech Connect

    Rehring, J.P.; Edwards, M.

    1996-04-01

    Copper corrosion was examined in the presence of natural organic matter (NOM) and in situations where NOM was altered by drinking water treatment. Corrosion rates (i{sub corr}) increased with higher NOM concentration at pH 6, whereas insignificant effects were observed at pH 7.5 and 9.0. Corrosion byproduct release was affected adversely by 4 mg/L NOM at pH 6.0, 7.5 and 9.0, with soluble copper increasing by 0.6 mg/L to 0.7 mg/L when compared to solutions without NOM. Alum-coagulated waters had higher i{sub corr} than untreated waters, but ferric chloride (FeCl{sub 3}{center_dot}6H{sub 2}O)-coagulated waters exhibited reduced i{sub corr}. This difference was attributed to the relative effects of added sulfate via alum coagulation vs added chloride via FeCl{sub 3}{center_dot}6H{sub 2}O coagulation. The effect of combined treatment (alum coagulation, ozonation, and granular activated carbon) was similar to that using alum coagulation alone.

  15. Corrosion prevention: Conversion coatings and coating processes. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect

    1996-10-01

    The bibliography contains citations of selected patents concerning conversion coatings and coating processes for the prevention of metal corrosion in various environments. Conversion coating patents for the application of phosphates and chromates to the surfaces of aluminum, zinc, ferrous metals, titanium, cadmium, iron, steels, and various alloys are presented. Topics include coating compositions, surface preparations and pretreatments prior to coating applications, post-treatment of coated metal surfaces, coating quality control, and sacrificial coatings for jet engines. Specific patents concerning protective coatings are excluded and covered in a separate bibliography. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  16. Corrosion prevention: Conversion coatings and coating processes. (Latest citations from the US Patent Bibliographic File with exemplary claims). Published Search

    SciTech Connect

    Not Available

    1994-11-01

    The bibliography contains citations of selected patents concerning conversion coatings and coating processes for the prevention of metal corrosion in various environments. Conversion coating patents for the application of phosphates and chromates to the surfaces of aluminum, zinc, ferrous metals, titanium, cadmium, iron, steels, and various alloys are presented. Topics include coating compositions, surface preparations and pretreatments prior to coating applications, post-treatment of coated metal surfaces, coating quality control, and sacrificial coatings for jet engines. Specific patents concerning protective coatings are excluded and covered in a separate bibliography. (Contains a minimum of 191 citations and includes a subject term index and title list.)

  17. Corrosion prevention: Conversion coatings and coating processes. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations of selected patents concerning conversion coatings and coating processes for the prevention of metal corrosion in various environments. Conversion coating patents for the application of phosphates and chromates to the surfaces of aluminum, zinc, ferrous metals, titanium, cadmium, iron, steels, and various alloys are presented. Topics include coating compositions, surface preparations and pretreatments prior to coating applications, post-treatment of coated metal surfaces, coating quality control, and sacrificial coatings for jet engines. Specific patents concerning protective coatings are excluded and covered in a separate bibliography. (Contains a minimum of 166 citations and includes a subject term index and title list.)

  18. Weldability characteristics of torr and corrosion-resistant TMT bars using SMAW process

    NASA Astrophysics Data System (ADS)

    Datta, Ramen; Veeraraghavan, R.; Rohira, K. L.

    2002-08-01

    Torr steel rebars, also known as cold twisted deformed (CTD) rebars, are used extensively for the construction of reinforced cement concrete (RCC) structures. These steels, which are characterized by a high carbon content and are subjected to a cold twisting operation to attain the desired strength level and bond strength, suffer from low ductility and poor bendability properties. Furthermore, these rebars are not suitable for coastal, humid, and industrial conditions where corrosion rates are very high. To combat these problems, recent efforts at the Steel Authority of India Limited (SAIL) have led to the successful development of corrosion-resistant thermomechanically treated (TMT) rebars with a minimum yield strength of 500 MPa. These rebars are characterized by a low carbon content, exhibit excellent strength-ductility-corrosion properties, and are rapidly replacing traditional torr rebars in corrosion-prone areas for a wide range of applications, namely, concrete reinforcement structures, bridges, flyovers on dams, etc. A comprehensive evaluation of the weldability properties of corrosion-resistant Cu-TMT rebars was carried out, and they were compared with those made of torr steel in order to assess their suitability for various structural applications. Implant and restraint cracking (RC) tests were carried out to assess the cold-cracking resistance of the weld joint under different welding conditions. The static fatigue limit (SFL) values were found to be similar, namely, 640 MPa (torr steel) and 625 MPa (Cu-TMT steel) under condition of no preheating and no rebaking using a heat input of 7.5 KJ/cm, indicating adequate cold-cracking resistance for both the steels. Restraint cracking tests yielded critical restraint intensities (Kcr) in excess of 16,800 MPa for both of the steels. Based on the weldability tests, the optimized conditions for welding were formulated and extensive tests were carried out on the welded joints. Both of the steels exhibited adequate

  19. Corrosion Behavior of Ultra-fine Grained 1050 Aluminum Alloy Fabricated by ARB Process in a Buffer Borate Solution

    NASA Astrophysics Data System (ADS)

    Fattah-alhosseini, A.; Gashti, S. O.

    2015-09-01

    Accumulative roll bonding (ARB) has been used as a severe plastic deformation process for the industrial production of ultra-fine grained (UFG) and nano-crystalline sheets with excellent mechanical properties. In the present study, the effect of the ARB process on the corrosion behavior of UFG and nano-crystalline 1050 aluminum alloy in a buffer borate solution (pH 5.5) has been investigated. The result of microhardness tests revealed that microhardness values increase with an increasing number of ARB cycles. A sharp increase in microhardness is seen after three ARB cycles, whereas moderate additional increases are observed afterward for up to nine cycles. Also, the XRD results showed that the mean crystallite size decreased to about 91 nm after nine cycles. The potentiodynamic plots show that as a result of ARB, the corrosion behavior of the UFG and nano-crystalline specimens improves, compared to the annealed 1050 aluminum alloy. Moreover, electrochemical impedance spectroscopy measurements showed that the polarization resistance increases with an increasing number of ARB cycles.

  20. A facile electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on carbon steel

    NASA Astrophysics Data System (ADS)

    Fan, Yi; He, Yi; Luo, Pingya; Chen, Xi; Liu, Bo

    2016-04-01

    Superhydrophobic Fe film with hierarchical micro/nano papillae structures is prepared on C45 steel surface by one-step electrochemical method. The superhydrophobic surface was measured with a water contact angle of 160.5 ± 0.5° and a sliding angle of 2 ± 0.5°. The morphology of the fabricated surface film was characterized by field emission scanning electron microscopy (FE-SEM), and the surface structure seems like accumulated hierarchical micro-nano scaled particles. Furthermore, according to the results of Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS), the chemical composition of surface film was iron complex with organic acid. Besides, the electrochemical measurements showed that the superhydrophobic surface improved the corrosion resistance of carbon steel in 3.5 wt.% NaCl solution significantly. The superhydrophobic layer can perform as a barrier and provide a stable air-liquid interface which inhibit penetration of corrosive medium. In addition, the as-prepared steel exhibited an excellent self-cleaning ability that was not favor to the accumulation of contaminants.

  1. The effects of microstructure on the corrosion of glycine/nitrate processed cermet inert anodes: A preliminary study

    SciTech Connect

    Windisch, Jr, C F; Chick, L A; Maupin, G D; Stice, N D

    1991-07-01

    The Inert Electrodes Program at the Pacific Northwest Laboratory (PNL) is supported by the Office of Industrial Processes of the US Department of Energy and is aimed at improving the energy efficiency of Hall-Heroult cells through the development of inert anodes. The inert anodes currently under the study are composed of a cermet material of the general composition NiO-NiFe{sub 2}O{sub 4}-Cu. The program has three primary objectives: (a) to evaluate the anode material in a scaled-up, pilot cell facility, (b) to investigate the mechanisms of the electrochemical reactions at the anodes surface, and (c) to develop sensors for monitoring various anode and/or electrolyte conditions. This report covers the results of a portion of the studies on anode reaction mechanisms. The anode mechanism studies were focused in four areas in FY 1990 and FY 1991: (a) the determination of whether a film formed on cermet inert anodes and (if it existed) the characterization of this film, (b) the determination of the sources of the anode impedance, (c) the evaluation of the effects of silica and a precorroded state on anode corrosion, and (d) a preliminary study on the effect of microstructure on the corrosion properties of the anodes. This report discusses the results of the microstructure studies. 6 refs., 32 figs., 3 tabs.

  2. Determination of corrosion rates for steel alloys in process solvent. Final technical report

    SciTech Connect

    Latos, E.J.

    1984-01-01

    The objectives of this program were to determine the corrosion rate, under static and dynamic conditions, of AISI 1010, 5 Cr-0.5 Mo, Type 304L and Type 316L steels in an SRC-I, V-178, coal-derived liquid at temperatures ranging from 550/sup 0/F (288/sup 0/C) to 700/sup 0/F (371/sup 0/C) and to analyze the after-test liquids for metal content, and physical and chemical properties to determine stability under these test conditions. In addition, the program included a study to determine the storage stability of the V-178 coal-derived liquid at 110/sup 0/F (43.3/sup 0/C) in air. 6 references, 32 figures, 35 tables.

  3. XPS and electrochemical impedance spectroscopy studies on effects of the porcelain firing process on surface and corrosion properties of two nickel-chromium dental alloys.

    PubMed

    Qiu, Jing; Tang, Chun-bo; Zhu, Zhi-jun; Zhou, Guo-xing; Wang, Jie; Yang, Yi; Wang, Guo-ping

    2013-11-01

    The aim of this study was to evaluate the effects of a simulated porcelain firing process on the surface, corrosion behavior and cell culture response of two nickel-chromium (Ni-Cr) dental alloys. A Be-free alloy and a Be-containing alloy were tested. Before porcelain firing, as-cast specimens were examined for surface composition using X-ray photoelectron spectroscopy and metallurgical phases using X-ray diffraction. Corrosion behaviors were evaluated using electrochemical impedance spectroscopy. 3T3 fibroblasts were cultured and exposed indirectly to specimens. MTT assays were counted after 3 and 6 days. The cell culture mediums exposed to specimens were analyzed for metal ion release. After porcelain firing, similar specimens were examined for the same properties. In both as-cast and fired conditions, the Be-free Ni-Cr alloy showed significantly more resistance to corrosion than the Be-containing Ni-Cr alloy, which exhibited BeNi phase. After porcelain firing, the corrosion resistance of the Be-free Ni-Cr alloy decreased statistically, corresponding with evident decreases of Cr and Ni oxides on the alloy surface. Also, the alloy's MTT assay decreased significantly corresponding with an obvious increase of Ni-ion release after the firing. For the Be-containing Ni-Cr alloy, the firing process led to increases of surface oxides and metallic Be, while its corrosion resistance and cell culture response were not significantly changed after porcelain firing. The results suggested that the corrosion resistance and biocompatibility of the Be-free Ni-Cr alloy decreased after porcelain firing, whereas the firing process had little effect on the same properties of the Be-containing Ni-Cr alloy. PMID:23881280

  4. XPS and electrochemical impedance spectroscopy studies on effects of the porcelain firing process on surface and corrosion properties of two nickel-chromium dental alloys.

    PubMed

    Qiu, Jing; Tang, Chun-bo; Zhu, Zhi-jun; Zhou, Guo-xing; Wang, Jie; Yang, Yi; Wang, Guo-ping

    2013-11-01

    The aim of this study was to evaluate the effects of a simulated porcelain firing process on the surface, corrosion behavior and cell culture response of two nickel-chromium (Ni-Cr) dental alloys. A Be-free alloy and a Be-containing alloy were tested. Before porcelain firing, as-cast specimens were examined for surface composition using X-ray photoelectron spectroscopy and metallurgical phases using X-ray diffraction. Corrosion behaviors were evaluated using electrochemical impedance spectroscopy. 3T3 fibroblasts were cultured and exposed indirectly to specimens. MTT assays were counted after 3 and 6 days. The cell culture mediums exposed to specimens were analyzed for metal ion release. After porcelain firing, similar specimens were examined for the same properties. In both as-cast and fired conditions, the Be-free Ni-Cr alloy showed significantly more resistance to corrosion than the Be-containing Ni-Cr alloy, which exhibited BeNi phase. After porcelain firing, the corrosion resistance of the Be-free Ni-Cr alloy decreased statistically, corresponding with evident decreases of Cr and Ni oxides on the alloy surface. Also, the alloy's MTT assay decreased significantly corresponding with an obvious increase of Ni-ion release after the firing. For the Be-containing Ni-Cr alloy, the firing process led to increases of surface oxides and metallic Be, while its corrosion resistance and cell culture response were not significantly changed after porcelain firing. The results suggested that the corrosion resistance and biocompatibility of the Be-free Ni-Cr alloy decreased after porcelain firing, whereas the firing process had little effect on the same properties of the Be-containing Ni-Cr alloy.

  5. Crude unit corrosion and corrosion control

    SciTech Connect

    Bagdasarian, A.; Feather, J.; Hull, B.; Stephenson, R.; Strong, R.

    1996-08-01

    In the petroleum refining process, the Crude Unit is the initial stage of distillation of the crude oil into useable fractions, either as end products or feed to downstream units. The major pieces of equipment found on units will vary depending on factors such as the assay of the design crude, the age of the refinery, and other downstream units. The unit discussed in this paper has all of the major pieces of equipment found on crude units including double desalting, a preflash section, an atmospheric section, a vacuum section, and a stabilization section. This paper reviews fundamental corrosion issues concerning the Crude Unit process. It is, in concise form, a description of the process and major equipment found in the Crude Unit; types of corrosion and where they occur; corrosion monitoring and inspection advice; and a list of related references for further reading. 12 refs., 1 fig.

  6. Effect of different processings on mechanical property and corrosion behavior in simulated body fluid of Mg-Zn-Y-Nd alloy for cardiovascular stent application

    NASA Astrophysics Data System (ADS)

    Zhu, Shi-Jie; Liu, Qian; Qian, Ya-Feng; Sun, Bin; Wang, Li-Guo; Wu, Jing-Min; Guan, Shao-Kang

    2014-09-01

    The biomagnesium alloys have been considered to be one of the most potential biodegradable metal materials due to its good mechanical compatibility, biological compatibility, biological security and biodegradable characteristics. However, the two major problems of high degradation rates in physiological environment and low mechanical properties prevent the development of biomagnesium alloys. In the present work, the samples of Mg-Zn-Y-Nd alloy were prepared by cyclic extrusion compression (CEC) and equal channel angular pressing (ECAP). The microstructures, mechanical properties of alloy and its corrosion behavior in simulated body fluid (SBF) were evaluated. The results reveal that Mg-Zn-Y-Nd alloy consists of equiaxial fine grain structure with the homogeneous distribution of micrometer size and nano-sized second phase, which was caused by the dynamic recrystallization during the ECAP and CEC. The corrosion resistance of alloy was improved. The tensile and corrosion resistance were improved, especially the processed alloy exhibit uniform corrosion performances and decreased corrosion rate. This will provide theoretical ground for Mg-Zn-Y-Nd alloy as vascular stent application.

  7. One-step electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on magnesium alloy.

    PubMed

    Liu, Qin; Chen, Dexin; Kang, Zhixin

    2015-01-28

    A simple, one-step method has been developed to construct a superhydrophobic surface by electrodepositing Mg-Mn-Ce magnesium plate in an ethanol solution containing cerium nitrate hexahydrate and myristic acid. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were employed to characterize the surfaces. The shortest electrodeposition time to obtain a superhydrophobic surface was about 1 min, and the as-prepared superhydrophobic surfaces had a maximum contact angle of 159.8° and a sliding angle of less than 2°. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements demonstrated that the superhydrophobic surface greatly improved the corrosion properties of magnesium alloy in 3.5 wt % aqueous solutions of NaCl, Na2SO4, NaClO3, and NaNO3. Besides, the chemical stability and mechanical durability of the as-prepared superhydrophobic surface were also examined. The presented method is rapid, low-cost, and environmentally friendly and thus should be of significant value for the industrial fabrication of anticorrosive superhydrophobic surfaces and should have a promising future in expanding the applications of magnesium alloys.

  8. One-step electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on magnesium alloy.

    PubMed

    Liu, Qin; Chen, Dexin; Kang, Zhixin

    2015-01-28

    A simple, one-step method has been developed to construct a superhydrophobic surface by electrodepositing Mg-Mn-Ce magnesium plate in an ethanol solution containing cerium nitrate hexahydrate and myristic acid. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were employed to characterize the surfaces. The shortest electrodeposition time to obtain a superhydrophobic surface was about 1 min, and the as-prepared superhydrophobic surfaces had a maximum contact angle of 159.8° and a sliding angle of less than 2°. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements demonstrated that the superhydrophobic surface greatly improved the corrosion properties of magnesium alloy in 3.5 wt % aqueous solutions of NaCl, Na2SO4, NaClO3, and NaNO3. Besides, the chemical stability and mechanical durability of the as-prepared superhydrophobic surface were also examined. The presented method is rapid, low-cost, and environmentally friendly and thus should be of significant value for the industrial fabrication of anticorrosive superhydrophobic surfaces and should have a promising future in expanding the applications of magnesium alloys. PMID:25559356

  9. Mobile evaporator corrosion test results

    SciTech Connect

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80{degrees}C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either {open_quotes}satisfactory{close_quotes} (2-20 mpy) or {open_quotes}excellent{close_quotes} (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment.

  10. Microstructure Evolution and Corrosion Property of Medium-Carbon Alloy Steel after High-Temperature Carburization Process

    NASA Astrophysics Data System (ADS)

    Dewei, Deng; Tingting, Niu; Haiying, Liu; Lin, Zhang; Qi, Sun

    2016-04-01

    In the present study, the effects of carburization treatment on the microstructure and corrosion property of medium-carbon steels (40Cr) were investigated by means of X-ray diffraction (XRD), electron microprobe analyzer (EMPA), optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and electrochemical corrosion, respectively. It was found that the microstructures beneath the surface were refined and a smooth transition microstructure from the surface to the core was observed in carburized samples. The fine plate-like but not granular carbide precipitation (Cr7C3) was observed in carburized sample by heat-treatment. The carburized specimens exhibited some effectiveness in the improvement of hardness and a smooth transition hardness profile. Corrosion resistance of 40Cr was improved by carburization treatment, resulting in the higher self-corrosion potential and the lower self-corrosion current density.

  11. Long-Term Corrosion Processes of Iron and Steel Shipwrecks in the Marine Environment: A Review of Current Knowledge

    NASA Astrophysics Data System (ADS)

    Moore, James D.

    2015-12-01

    Methodologies for examining the corrosion behavior of iron and steel shipwrecks have steadily progressed since the 1970s, but the analytical techniques utilized since then are comparatively site-specific, and the overall quantity of data available for independent review is seemingly limited. Laudable advancements in the fields of maritime archaeology, oceanography, and corrosion science support the determination that microbiologically-influenced corrosion primarily controls the degradation rates of iron and steel shipwrecks over archaeological timescales. Future in situ analyses performed on these shipwreck sites need to consider the overreaching impacts that microbiological metabolism have on long-term corrosion rates. The corrosion behavior of an iron or steel archaeological shipwreck site should also not be readily applied to similar sites or to other wrecked vessels that are in close proximity.

  12. Corrosivity Of Pyrolysis Oils

    SciTech Connect

    Keiser, James R; Bestor, Michael A; Lewis Sr, Samuel Arthur; Storey, John Morse

    2011-01-01

    Pyrolysis oils from several sources have been analyzed and used in corrosion studies which have consisted of exposing corrosion coupons and stress corrosion cracking U-bend samples. The chemical analyses have identified the carboxylic acid compounds as well as the other organic components which are primarily aromatic hydrocarbons. The corrosion studies have shown that raw pyrolysis oil is very corrosive to carbon steel and other alloys with relatively low chromium content. Stress corrosion cracking samples of carbon steel and several low alloy steels developed through-wall cracks after a few hundred hours of exposure at 50 C. Thermochemical processing of biomass can produce solid, liquid and/or gaseous products depending on the temperature and exposure time used for processing. The liquid product, known as pyrolysis oil or bio-oil, as produced contains a significant amount of oxygen, primarily as components of water, carboxylic acids, phenols, ketones and aldehydes. As a result of these constituents, these oils are generally quite acidic with a Total Acid Number (TAN) that can be around 100. Because of this acidity, bio-oil is reported to be corrosive to many common structural materials. Despite this corrosive nature, these oils have the potential to replace some imported petroleum. If the more acidic components can be removed from this bio-oil, it is expected that the oil could be blended with crude oil and then processed in existing petroleum refineries. The refinery products could be transported using customary routes - pipelines, barges, tanker trucks and rail cars - without a need for modification of existing hardware or construction of new infrastructure components - a feature not shared by ethanol.

  13. Structurally Integrated Coatings for Wear and Corrosion (SICWC): Arc Lamp, InfraRed (IR) Thermal Processing

    SciTech Connect

    Mackiewicz-Ludtka, G.; Sebright, J.

    2007-12-15

    The primary goal of this Cooperative Research and Development Agreement (CRADA) betwe1311 UT-Battelle (Contractor) and Caterpillar Inc. (Participant) was to develop the plasma arc lamp (PAL), infrared (IR) thermal processing technology 1.) to enhance surface coating performance by improving the interfacial bond strength between selected coatings and substrates; and 2.) to extend this technology base for transitioning of the arc lamp processing to the industrial Participant. Completion of the following three key technical tasks (described below) was necessary in order to accomplish this goal. First, thermophysical property data sets were successfully determined for composite coatings applied to 1010 steel substrates, with a more limited data set successfully measured for free-standing coatings. These data are necessary for the computer modeling simulations and parametric studies to; A.) simulate PAL IR processing, facilitating the development of the initial processing parameters; and B.) help develop a better understanding of the basic PAL IR fusing process fundamentals, including predicting the influence of melt pool stirring and heat tnmsfar characteristics introduced during plasma arc lamp infrared (IR) processing; Second, a methodology and a set of procedures were successfully developed and the plasma arc lamp (PAL) power profiles were successfully mapped as a function of PAL power level for the ORNL PAL. The latter data also are necessary input for the computer model to accurately simulate PAL processing during process modeling simulations, and to facilitate a better understand of the fusing process fundamentals. Third, several computer modeling codes have been evaluated as to their capabilities and accuracy in being able to capture and simulate convective mixing that may occur during PAL thermal processing. The results from these evaluation efforts are summarized in this report. The intention of this project was to extend the technology base and provide for

  14. Corrosion Engineering.

    ERIC Educational Resources Information Center

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  15. Fireside Corrosion

    SciTech Connect

    Holcomb, Gordon

    2011-07-14

    Oxy-fuel fireside research goals are: (1) determine the effect of oxyfuel combustion on fireside corrosion - flue gas recycle choice, staged combustion ramifications; and (2) develop methods to use chromia solubility in ash as an ash corrosivity measurement - synthetic ashes at first, then boiler and burner rig ashes.

  16. Corrosion inhibitor

    SciTech Connect

    Wisotsky, M.J.; Metro, S.J.

    1989-10-31

    A corrosion inhibitor for use in synthetic ester lubricating oils is disclosed. It comprises an effective amount of: at least one aromatic amide; and at least one hydroxy substituted aromatic compound. The corrosion inhibitor thus formed is particularly useful in synthetic ester turbo lubricating oils.

  17. Corrosion sensor

    DOEpatents

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  18. Corrosion sensor

    DOEpatents

    Glass, R.S.; Clarke, W.L. Jr.; Ciarlo, D.R.

    1994-04-26

    A corrosion sensor array is described incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis. 7 figures.

  19. Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water.

    PubMed

    Zuo, R; Ornek, D; Syrett, B C; Green, R M; Hsu, C-H; Mansfeld, F B; Wood, T K

    2004-04-01

    Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50-90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel. PMID:12898064

  20. Effect of Cr/C Ratio on Microstructure and Corrosion Performance of Cr3C2-NiCr Composite Fabricated by Laser Processing

    NASA Astrophysics Data System (ADS)

    Lou, Deyuan; Liu, Dun; He, Chunlin; Bennett, Peter; Chen, Lie; Yang, Qibiao; Fearon, Eamonn; Dearden, Geoff

    2016-01-01

    The present study focuses on the effect of different Cr/C ratios on the microstructure, microhardness, and corrosion resistance of Ni-based laser clad hardfacings, reinforced by in situ synthesized chromium carbide particles. Cr3C2-NiCr composites have been laser processed with graphite/Cr/Ni powder blends with varying Cr/C ratios. Following phase analysis (x-ray diffraction) and microstructure investigation (scanning electron microscopy; energy dispersive x-ray analysis; transmission electron microscopy), the solidification of laser melt pool is discussed, and the corrosion resistances are examined. Several different zones (planar, dendritic, eutectic and re-melt zone) were formed in these samples, and the thicknesses and shapes of these zones vary with the change of Cr/C ratio. The sizes and types of carbides and the content of reserved graphite in the composites change as the Cr/C ratio varies. With the content of carbides (especially Cr3C2) grows, the microhardness is improved. The corrosive resistance of the composites to 0.2M H2SO4 aqueous solution decreases as the Cr/C ratio reduces owing to not only the decreasing Cr content in the NiCr matrix but also the galvanic corrosion formed within the carbide and graphite containing Ni matrix.

  1. Chemical Species in the Vapor Phase of Hanford Double-Shell Tanks: Potential Impacts on Waste Tank Corrosion Processes

    SciTech Connect

    Felmy, Andrew R.; Qafoku, Odeta; Arey, Bruce W.; Boomer, Kayle D.

    2010-09-22

    The presence of corrosive and inhibiting chemicals on the tank walls in the vapor space, arising from the waste supernatant, dictate the type and degree of corrosion that occurs there. An understanding of how waste chemicals are transported to the walls and the affect on vapor species from changing supernatant chemistry (e.g., pH, etc.), are basic to the evaluation of risks and impacts of waste changes on vapor space corrosion (VSC). In order to address these issues the expert panel workshop on double-shell tank (DST) vapor space corrosion testing (RPP-RPT-31129) participants made several recommendations on the future data and modeling needs in the area of DST corrosion. In particular, the drying of vapor phase condensates or supernatants can form salt or other deposits at the carbon steel interface resulting in a chemical composition at the near surface substantially different from that observed directly in the condensates or the supernatants. As a result, over the past three years chemical modeling and experimental studies have been performed on DST supernatants and condensates to predict the changes in chemical composition that might occur as condensates or supernatants equilibrate with the vapor space species and dry at the carbon steel surface. The experimental studies included research on both the chemical changes that occurred as the supernatants dried as well as research on how these chemical changes impact the corrosion of tank steels. The chemical modeling and associated experimental studies were performed at the Pacific Northwest National Laboratory (PNNL) and the research on tank steel corrosion at the Savannah River National Laboratory (SRNL). This report presents a summary of the research conducted at PNNL with special emphasis on the most recent studies conducted in FY10. An overall summary of the project results as well as their broader implications for vapor space corrosion of the DST’s is given at the end of this report.

  2. Benefits of thread rolling process to the stress corrosion cracking and fatigue resistance of high strength fasteners

    SciTech Connect

    Kephart, A.R.; Hayden, S.Z.

    1993-05-01

    Stress corrosion cracking (SCC) behavior of cut (machined) vice thread rolled Alloy X-750 and Alloy 625 fasteners in a simulated high temperature primary water environment has been evaluated. SCC testing at 360 and 338C included 157 small and 40 large 60{degree} Vee thread studs. Thread rolled fasteners had improved resistance relative to cut fasteners. Tests of fatigue resistance in air at room temperature and both air and primary water at 315C were conducted on smaller studs with both cut and rolled threads. Results showed rolled threads can have significantly improved fatigue lives over those of cut threads in both air and primary water. Fasteners produced by two different thread rolling methods, in-feed (radial) and through-feed (axial), revealed similar SCC initiation test results. Testing of thread rolled fasteners revealed no significant SCC or fatigue growth of rolling induced thread crest laps typical of the thread rolling process. While fatigue resistance differed between the two rolled thread supplier`s studs, neither of the suppliers studs showed SCC initiation at exposure times beyond that of cut threads with SCC. In contrast to rolling at room temperature, warm rolled (427C) threads showed no improvement over cut threads in terms of fatigue resistance. The observed improved SCC and fatigue performance of rolled threads is postulated to be due to interactive factors, including beneficial residual stresses in critically stressed thread root region, reduction of plastic strains during loading and formation of favorable microstructure.

  3. Corrosion testing in natural waters: Second volume

    SciTech Connect

    Kain, R.M.; Young, W.T.

    1997-12-31

    This is the second STP of the same title. The first volume, STP 1086, was published in 1990 and contained papers on seawater corrosivity, crevice corrosion resistance of stainless steels, corrosion fatigue testing, and corrosion in potable water. Since then, final results have become available from the worldwide study on corrosion behavior of metals in seawater, and additional studies have been performed that should be brought to the attention of the corrosion engineering community. The second volume contains these studies. Papers have been processed separately for inclusion on the data base.

  4. Effects of aging temperature and time on the corrosion protection provided by trivalent chromium process coatings on AA2024-T3.

    PubMed

    Li, Liangliang; Swain, Greg M

    2013-08-28

    The effects of aging temperature and time on the physical structure of and corrosion protection provided by trivalent chromium process (TCP) coatings on AA2024-T3 are reported. The TCP coating forms a partially blocking barrier layer on the alloy surface that consists of hydrated channels and or defects. It is through these channels and defects that ions and dissolved O2 can be transported to small areas of the underlying alloy. Reactions initiate at these sites, which can ultimately lead to undercutting of the coating and localized corrosion. We tested the hypothesis that collapsing the channels and or reducing the number of defects in the coating might be possible through post-deposition heat treatment, and that this would enhance the corrosion protection provided by the coating. This was tested by aging the TCP-coated AA2024 alloys in air overnight at room temperature (RT), 55, 100, or 150 °C. The TCP coating became dehydrated and thinner at the high temperatures (55 and 100 °C). This improved the corrosion protection as evidenced by a 2× increase in the charge transfer resistance. Aging at 150 °C caused excessive coating dehydration and shrinkage. This led to severe cracking and detachment of the coating from the surface. The TCP-coated AA2024 samples were also aged in air at RT from 1 to 7 days. There was no thinning of the coating, but the corrosion protection was enhanced with a longer aging period as evidenced by a 4× increase in the charge transfer resistance. The coating became more hydrophobic after aging at elevated temperature (up to 100 °C) and with aging time at RT as evidenced by an increased water contact angle from 7 to 100 °C.

  5. Corrosion beneath disbonded pipeline coatings

    SciTech Connect

    Beavers, J.A.; Thompson, N.G.

    1997-04-01

    The relationship between coatings, cathodic protection (CP), and external corrosion of underground pipelines is described. Historically, this problem has been addressed by focusing on the corrosion and CP processes associated with holidays, e.g., coating disbondment and CP current flow within the disbonded region. These issues and those associated with disbonded areas distant from holidays are also discussed.

  6. Study of Acidithiobacillus ferrooxidans and enzymatic bio-Fenton process-mediated corrosion of copper-nickel alloy.

    PubMed

    Jadhav, U; Hocheng, H

    2016-10-01

    This study presents the corrosion behavior of the copper-nickel (Cu-Ni) alloy in the presence of Acidithiobacillus ferrooxidans (A. ferrooxidans) and glucose oxidase (GOx) enzyme. In both the cases ferric ions played an important role in weight loss and thereby to carry out the corrosion of the Cu-Ni alloy. A corrosion rate of 0.6 (±0.008), 2.11 (±0.05), 3.69 (±0.26), 0.7 (±0.006) and 0.08 (±0.002) mm/year was obtained in 72 h using 9K medium with ferrous sulfate, A. ferrooxidans culture supernatant, A. ferrooxidans cells, GOx enzyme and hydrogen peroxide (H2O2) solution respectively. The scanning electron microscopy (SEM) micrographs showed that a variable extent of corrosion was caused by 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells. An arithmetic average surface roughness (Ra) of 174.78 nm was observed for the control work-piece using optical profilometer. The change in Ra was observed with the treatment of the Cu-Ni alloy using various systems. The Ra for 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells was 374.54, 607.32 and 799.48 nm, respectively, after 24 h. These results suggest that A. ferrooxidans cells were responsible for more corrosion of the Cu-Ni alloy than other systems used.

  7. Corrosion beneath disbonded coatings: A review

    SciTech Connect

    Beavers, J.A.; Thompson, N.G.

    1996-12-01

    This paper describes the relationship between coatings, cathodic protection (CP), and external corrosion of underground pipelines. Historically, this problem has been addressed by focusing on the corrosion and CP processes associated with holidays, e.g., coating disbandment and CP current flow within the disbanded region. This paper addresses these issues but also considers corrosion associated with disbanded areas that are distant from holidays.

  8. Fighting Corrosion

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Reinforced concrete structures such as bridges, parking decks, and balconies are designed to have a service life of over 50 years. All too often, however, many structures fall short of this goal, requiring expensive repairs and protection work earlier than anticipated. The corrosion of reinforced steel within the concrete infrastructure is a major cause for this premature deterioration. Such corrosion is a particularly dangerous problem for the facilities at NASA s Kennedy Space Center. Located near the Atlantic Ocean in Florida, Kennedy is based in one of the most corrosive-prone areas in the world. In order to protect its launch support structures, highways, pipelines, and other steel-reinforced concrete structures, Kennedy engineers developed the Galvanic Liquid Applied Coating System. The system utilizes an inorganic coating material that slows or stops the corrosion of reinforced steel members inside concrete structures. Early tests determined that the coating meets the criteria of the National Association of Corrosion Engineers for complete protection of steel rebar embedded in concrete. Testing is being continued at the Kennedy's Materials Science Beach Corrosion Test Site.

  9. Naphthenic acid corrosion in the refinery

    SciTech Connect

    Craig, H.L. Jr.

    1995-11-01

    Field tests and laboratory studies of refinery process streams are presented. The effects of temperature, velocity and physical state were studied with respect to alloy selection for corrosion resistant service. The amount of molybdenum in the austenitic stainless steel alloys is the dominant factor in conferring corrosion resistance. The Naphthenic Acid Corrosion Index (NACI) is useful in assessing the severity of corrosion under a variety of circumstances.

  10. Monitoring power plant fireside corrosion using corrosion probes

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, M.

    2005-01-01

    The ability to monitor the corrosion degradation of key components in fossil fuel power plants is of utmost importance for Futuregen and ultra-supercritical power plants. Fireside corrosion occurs in the high temperature sections of energy production facilities due to a number of factors: ash deposition, coal composition, thermal gradients, and low NOx conditions, among others. Problems occur when equipment designed for either oxidizing or reducing conditions is exposed to alternating oxidizing and reducing conditions. This can happen especially near the burners. The use of low NOx burners is becoming more commonplace and can produce reducing environments that accelerate corrosion. One method of addressing corrosion of these surfaces is the use of corrosion probes to monitor when process changes cause corrosive conditions. In such a case, corrosion rate could become a process control variable that directs the operation of a coal combustion or coal gasification system. Alternatively, corrosion probes could be used to provide an indication of total metal damage and thus a tool to schedule planned maintenance outages.

  11. Fireside corrosion probes--an update

    SciTech Connect

    Covino, B.S., Jr.; Bullard, S.J.; Holcomb, G.R.; Ziomek-Moroz, M.; Matthes, S.A.

    2007-01-01

    The ability to monitor the corrosion degradation of key metallic components in fossil fuel power plants will become increasingly important for FutureGen and ultra-supercritical power plants. A number of factors (ash deposition, coal composition changes, thermal gradients, and low NOx conditions, among others) which occur in the high temperature sections of energy production facilities, will contribute to fireside corrosion. Several years of research have shown that high temperature corrosion rate probes need to be better understood before corrosion rate can be used as a process variable by power plant operators. Our recent research has shown that electrochemical corrosion probes typically measure lower corrosion rates than those measured by standard mass loss techniques. While still useful for monitoring changes in corrosion rates, absolute probe corrosion rates will need a calibration factor to be useful. Continuing research is targeted to help resolve these issues.

  12. Evaluation of electric arc furnace-processed steel slag for dermal corrosion, irritation, and sensitization from dermal contact.

    PubMed

    Suh, Mina; Troese, Matthew J; Hall, Debra A; Yasso, Blair; Yzenas, John J; Proctor, Debora M

    2014-12-01

    Electric arc furnace (EAF) steel slag is alkaline (pH of ~11-12) and contains metals, most notably chromium and nickel, and thus has potential to cause dermal irritation and sensitization at sufficient dose. Dermal contact with EAF slag occurs in many occupational and environmental settings because it is used widely in construction and other industrial sectors for various applications including asphaltic paving, road bases, construction fill, and as feed for cement kilns construction. However, no published study has characterized the potential for dermal effects associated with EAF slag. To assess dermal irritation, corrosion and sensitizing potential of EAF slag, in vitro and in vivo dermal toxicity assays were conducted based on the Organisation for Economic Co-operation and Development (OECD) guidelines. In vitro dermal corrosion and irritation testing (OECD 431 and 439) of EAF slag was conducted using the reconstructed human epidermal (RHE) tissue model. In vivo dermal toxicity and delayed contact sensitization testing (OECD 404 and 406) were conducted in rabbits and guinea pigs, respectively. EAF slag was not corrosive and not irritating in any tests. The results of the delayed contact dermal sensitization test indicate that EAF slag is not a dermal sensitizer. These findings are supported by the observation that metals in EAF slag occur as oxides of low solubility with leachates that are well below toxicity characteristic leaching procedure (TCLP) limits. Based on these results and in accordance to the OECD guidelines, EAF slag is not considered a dermal sensitizer, corrosive or irritant.

  13. Impacts of Transport Properties of Porous Corrosion Product Layer on Effective Corrosion Rate

    NASA Astrophysics Data System (ADS)

    Li, Xiaobai; Cook, David

    2012-11-01

    Condensing exhaust gases containing H2O, SO3 and NOx cause serious corrosion failure in various industry processes. For example, in modern compact heat cells, corrosion products deposit on top of the heat exchanger cooling fins, blocking the flow passages and drastically decreasing system performance. The transport properties of porous corrosion product layers play important role in determining the corrosion tendency and observed corrosion rate. To understand the corrosion mechanism for Aluminum alloy in sulfuric acid environment, impacts of transport properties of corrosion residual layers are investigated with different numerical models for porous layer diffusivity. The effective corrosion rates resulted from these models are compared to corresponding experimental measurements. A multilayer diffusivity model in which diffusivity depends both on porous layer structure and composition shows excellent agreements with experimental data. This model is currently being used in a multi-scale flow simulation framework to predict corrosion phenomena in heat cells.

  14. A comparison of corrosion, tribocorrosion and electrochemical impedance properties of pure Ti and Ti6Al4V alloy treated by micro-arc oxidation process

    NASA Astrophysics Data System (ADS)

    Fazel, M.; Salimijazi, H. R.; Golozar, M. A.; Garsivaz jazi, M. R.

    2015-01-01

    In this paper, the micro-arc oxidation (MAO) coatings were performed on pure Ti and Ti6Al4V samples at 180 V. The results indicated that unlike the volcanic morphology of oxide layer on pure Ti, a cortex-like morphology with irregular vermiform slots was seen on MAO/Ti6Al4V sample. According to polarization curves, the corrosion resistance of untreated samples was significantly increased by MAO process. The electrochemical impedance spectroscopy analysis showed a lower capacitance of barrier layer (led to higher resistance) for MAO/Ti specimens. This indicates that corrosive ions diffusion throughout the oxide film would be more difficult resulted in a higher corrosion resistance. Tribocorrosion results illustrated that the potential of untreated samples was dropped sharply to very low negative values. However, the lower wear volume loss was achieved for Ti6Al4V alloy. SEM images of worn surfaces demonstrated the local detachment of oxide layer within the wear track of MAO/Ti sample. Conversely, no delamination was detected in MAO/Ti6Al4V and a mild abrasive wear was the dominant mechanism.

  15. Effect of corrosion and stress-corrosion cracking on pipe integrity and remaining life

    SciTech Connect

    Jaske, C.E.; Beavers, J.A.

    1996-07-01

    Process piping is often exposed to corrosive fluids. During service, such exposure may cause localized corrosion or stress-corrosion cracking that affects structural integrity. This paper presents a model that quantifies the effect of localized corrosion and stress-corrosion cracking on pipe failure stress. The model is an extension of those that have been developed for oil and gas pipelines. It accounts for both axial and hoop stress. Cracks are modeled using inelastic fracture mechanics. Both flow-stress and fracture-toughness dependent failure modes are addressed. Corrosion and crack-growth rates are used to predict remaining service life.

  16. Solving A Corrosion Problem

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The corrosion problem, it turned out, stemmed from the process called electrolysis. When two different metals are in contact, an electrical potential is set up between them; when the metals are surrounded by an electrolyte, or a conducting medium, the resulting reaction causes corrosion, often very rapid corrosion. In this case the different metals were the copper grounding system and the ferry's aluminum hull; the dockside salt water in which the hull was resting served as the electrolyte. After identifying the source of the trouble, the Ames engineer provided a solution: a new wire-and-rod grounding system made of aluminum like the ferry's hull so there would no longer be dissimilar metals in contact. Ames research on the matter disclosed that the problem was not unique to the Golden Gate ferries. It is being experienced by many pleasure boat operators who are probably as puzzled about it as was the Golden Gate Transit Authority.

  17. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    NASA Astrophysics Data System (ADS)

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K.

    2015-11-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

  18. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion.

    PubMed

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K

    2015-11-30

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

  19. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    PubMed Central

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K.

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys. PMID:26615896

  20. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion.

    PubMed

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys. PMID:26615896

  1. Corrosion behavior of 8090 Al-Li alloy

    SciTech Connect

    Hu, Z.Q.; Zhang, Y.; Liu, Y.L. . Inst. of Metal Research); Zhu, Z.Y. . Inst. of Corrosion and Protection of Metals)

    1993-06-01

    An evaluation was conducted of the corrosion behavior of 8090 aluminum-lithium (Al-Li) alloy (UNS A98090), when aged under various conditions and subjected to corrosion in a solution of 3.5% NaCl + 1% H[sub 2]O[sub 2]. Susceptibility to pitting, intergranular corrosion, and exfoliation corrosion was shown to be influenced by heat treatment, which reduced from natural aging, through overaging to peak aging, Materials with peak aging showed low corrosion resistance. The decreased corrosion resistance corresponded to decreased corrosion potential of the alloy. Insoluble constituents were susceptible to corrosion. The corrosion extended along grain boundaries. Al-Li alloys showed mismatched tensile strength and stress corrosion resistance. The growth rate of stress corrosion cracks was large in the peak-aged state. The growth rate was strengthened by overaging, but tensile strength was reduced. That problem was solved by retrogression and reaging processing.

  2. Optimisation of mass ranging for atom probe microanalysis and application to the corrosion processes in Zr alloys.

    PubMed

    Hudson, D; Smith, G D W; Gault, B

    2011-05-01

    Atom probe tomography uses time-of-flight mass spectrometry to identify the chemical nature of atoms from their mass-to-charge-state ratios. Within a mass spectrum, ranges are defined so as to attribute a chemical identity to each peak. The accuracy of atom probe microanalysis relies on the definition of these ranges. Here we propose and compare several automated ranging techniques, tested against simulated mass spectra. The performance of these metrics compare favourably with a trial of users asked to manually range a simplified simulated dataset. The optimised automated ranging procedure was then used to precisely evaluate the very low iron concentration (0.003-0.018 at%) in a zirconium alloy to reveal its behaviour in the matrix during corrosion; oxygen is injected into solution and has the effect of increasing the local iron concentration near the oxide-metal interface, which in turn affects the corrosion properties of the metal substrate.

  3. Corrosion processes of austenitic stainless steels and copper-based materials in gamma-irradiated aqueous environments

    SciTech Connect

    Glass, R.S.

    1985-09-01

    The US Department of Energy is evaluating a site located at Yucca Mountain in Nye County, Nevada, as a potential high-level nuclear waste repository. The rock at the proposed repository horizon (above the water table) is densely welded, devitrified tuff, and the fluid environment in the repository is expected to be primarily air-steam. A more severe environment would be present in the unlikely case of intrusion of vadose groundwater into the repository site. For this repository location, austenitic stainless steels and copper-based materials are under consideration for waste container fabrication. This study focuses on the effects of gamma irradiation on the electrochemical mechanisms of corrosion for the prospective waste container materials. The radiolytic production of such species as hydrogen peroxide and nitric acid are shown to exert an influence on corrosion mechanisms and kinetics.

  4. Chemical processes involved in the initiation of hot corrosion of B-1900 and NASA-TRW VIA

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1979-01-01

    Sodium sulfate induced hot corrosion of B-1900 and NASA-TRW VIA at 900 C was studied with special emphasis on the chemical reactions occurring during and immediately after the induction period. Thermogravimetric tests were run for set periods of time after which the samples were washed with water and water soluable metal salts and/or residual sulfates were analyzed chemically. Element distributions within the oxide layer were obtained from electron microprobe X-ray micrographs. A third set of samples were subjected to surface analysis by X-ray photoelectron spectroscopy. Evolution of SO2 was monitored throughout many of the hot corrosion tests. Results are interpreted in terms of acid-base fluxing mechanisms.

  5. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.

    2010-01-01

    Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where they are needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into the microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy.

  6. Embrittlement and intergranular stress corrosion cracking of stainless steels after elevated temperature exposure in refinery process units

    SciTech Connect

    Cantwell, J.E.

    1985-01-01

    This paper reports on a survey by the Subcommittee on Corrosion and Materials Engineering of the Committee on Refinery Equipment. The purpose of the survey was to determine and record the extent of industry problems with loss of ductility or embrittlement of chromium and chromium nickel stainless steels and the intergranular cracking problem with chromium nickel stainless steels in fluid catalytic cracking units. Over 100 incidents are reported.

  7. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    SciTech Connect

    K.G. Mon

    2004-10-01

    The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

  8. CORROSION INHIBITION

    DOEpatents

    Cartledge, G.H.

    1958-06-01

    The protection of ferrous metsls from the corrosive action of aqueous solutions is accomplished by the incorporation of small amounts of certain additive agents into the aqueous solutions. The method comprises providing a small concentration of technetium, in the form of pertechnetate ion, dissolved in the solution.

  9. Atmospheric corrosion of metals in industrial city environment.

    PubMed

    Kusmierek, Elzbieta; Chrzescijanska, Ewa

    2015-06-01

    Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust.

  10. Atmospheric corrosion of metals in industrial city environment

    PubMed Central

    Kusmierek, Elzbieta; Chrzescijanska, Ewa

    2015-01-01

    Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust. PMID:26217736

  11. The dual role of microbes in corrosion.

    PubMed

    Kip, Nardy; van Veen, Johannes A

    2015-03-01

    Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion. PMID:25259571

  12. The dual role of microbes in corrosion

    PubMed Central

    Kip, Nardy; van Veen, Johannes A

    2015-01-01

    Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion. PMID:25259571

  13. The dual role of microbes in corrosion.

    PubMed

    Kip, Nardy; van Veen, Johannes A

    2015-03-01

    Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion.

  14. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    SciTech Connect

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-15

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  15. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes.

    PubMed

    Wiesinger, R; Schade, U; Kleber, Ch; Schreiner, M

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  16. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    NASA Astrophysics Data System (ADS)

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  17. Corrosion and corrosion prevention in gas turbines

    NASA Technical Reports Server (NTRS)

    Mom, A. J. A.; Kolkman, H. J.

    1985-01-01

    The conditions governing the corrosion behavior in gas turbines are surveyed. Factors such as temperature, relative humidity, the presence of sulfur and nitrogen dioxide, and fuel quality are discussed. Electromechanical corrosion at relatively low temperature in compressors; oxidation; and hot corrosion (sulfidation) at high temperature in turbines are considered. Corrosion prevention by washing and rinsing, fueld additives, and corrosion resistant materials and coatings are reviewed.

  18. Corrosion-resistant coating development

    SciTech Connect

    Stinton, D.P.; Kupp, D.M.; Martin, R.L.

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  19. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, L. M.; Hintze, P. E.; Li, W.; Buhrow, J. W.; Jolley, S. T.

    2011-01-01

    This slide presentation reviews the effects of corrosion on various structures at the Kennedy Space Center, and the work to discover a corrosion control coating that will be autonomous and will indicate corrosion at an early point in the process. Kennedy Space Center has many environmental conditions that are corrosive: ocean salt spray, heat, humidity, sunlight and acidic exhaust from the Solid Rocket Boosters (SRBs). Presented is a chart which shows the corrosion rates of carbon steel at various locations. KSC has the highest corrosion rates with 42.0 mils/yr, leading the next highest Galeta Point Beach, in the Panama Canal Zone with 27 mils/yr corrosion. A chart shows the changes in corrosion rate with the distance from the ocean. The three types of corrosion protective coatings are described: barrier (passive), Barrier plus active corrosion inhibiting components, and smart. A smart coating will detect and respond actively to changes in its environment in a functional and predictable manner and is capable of adapting its properties dynamically. The smart coating uses microcapsules, particles or liquid drops coated in polymers, that can detect and control the corrosion caused by the environment. The mechanism for a pH sensitive microcapsule and the hydrophobic core microcapsule are demonstrated and the chemistry is reviewed. When corrosion begins, the microcapsule will release the contents of the core (indicator, inhibitor, and self healing agent) in close proximity to the corrosion. The response to a pH increase is demonstrated by a series of pictures that show the breakdown of the microcapsule and the contents release. An example of bolt corrosion is used, as an example of corrosion in places that are difficult to ascertain. A comparison of various coating systems is shown.

  20. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  1. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan; Farmer, Joseph C.; Lee, Chuck K.; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  2. Metallurgical and Corrosion Characterization of POST Weld Heat Treated Duplex Stainless Steel (uns S31803) Joints by Friction Welding Process

    NASA Astrophysics Data System (ADS)

    Asif M., Mohammed; Shrikrishna, Kulkarni Anup; Sathiya, P.

    2016-02-01

    The present study focuses on the metallurgical and corrosion characterization of post weld heat treated duplex stainless steel joints. After friction welding, it was confirmed that there is an increase in ferrite content at weld interface due to dynamic recrystallization. This caused the weldments prone to pitting corrosion attack. Hence the post weld heat treatments were performed at three temperatures 1080∘C, 1150∘C and 1200∘C with 15min of aging time. This was followed by water and oil quenching. The volume fraction of ferrite to austenite ratio was balanced and highest pit nucleation resistance were achieved after PWHT at 1080∘C followed by water quench and at 1150∘C followed by oil quench. This had happened exactly at parameter set containing heating pressure (HP):40 heating time (HT):4 upsetting pressure (UP):80 upsetting time (UP):2 (experiment no. 5). Dual phase presence and absence of precipitates were conformed through TEM which follow Kurdjumov-Sachs relationship. PREN of ferrite was decreasing with increase in temperature and that of austenite increased. The equilibrium temperature for water quenching was around 1100∘C and that for oil quenching was around 1140∘C. The pit depths were found to be in the range of 100nm and width of 1.5-2μm.

  3. In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

    PubMed Central

    Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

    2013-01-01

    Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

  4. Structural evolution, thermomechanical recrystallization and electrochemical corrosion properties of Ni-Cu-Mg amorphous coating on mild steel fabricated by dual-anode electrolytic processing

    NASA Astrophysics Data System (ADS)

    Abdulwahab, M.; Fayomi, O. S. I.; Popoola, A. P. I.

    2016-07-01

    The electrolytic Ni-Cu based alloy coating with admixed interfacial blend of Mg have been successfully prepared on mild steel substrate by dual anode electroplating processes over a range of applied current density and dwell time. The electrocodeposition of Ni-Cu-Mg coating was investigated in the presence of other bath additives. The influence of deposition current on surface morphology, adhesion behavior, preferred crystal orientation, surface topography and electrochemical activity of Ni-Cu-Mg alloy coating on mild steel were systematically examined. The thermal stability of the developed composite materials was examined via isothermal treatment. Scanning electron microscope equipped with EDS, X-ray diffraction, Atomic force microscope, micro-hardness tester and 3 μmetrohm Potentiostat/galvanostat were used to compare untreated and isothermally treated electrocodeposited composite. The induced activity of the Ni-Cu-Mg alloy changed the surface modification and results to crystal precipitation within the structural interface by the formation of Cu, Ni2Mg3 phase. The obtained results showed that the introduction of Mg particles in the plating bath generally modified the surface and brings an increase in the hardness and corrosion resistance of Ni-Cu-Mg layers fabricated. Equally, isothermally treated composites demonstrated an improved properties indicating 45% increase in the micro-hardness and 79.6% corrosion resistance which further showed that the developed composite is thermally stable.

  5. Chemical Industry Corrosion Management

    SciTech Connect

    2003-02-01

    Improved Corrosion Management Could Provide Significant Cost and Energy Savings for the Chemical Industry. In the chemical industry, corrosion is often responsible for significant shutdown and maintenance costs.

  6. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Buhrow, J. W.; Zhang, X.; Johnsey, M. N.; Pearman, B. P.; Jolley, S. T.; Calle, L. M.

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry. The NASA Kennedy Space Centers Corrosion Technology Lab at the Kennedy Space Center in Florida, U.S.A. has been developing multifunctional smart coatings based on the microencapsulation of environmentally friendly corrosion

  7. Natural analogues of nuclear waste glass corrosion.

    SciTech Connect

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  8. Stress corrosion cracking evaluation of precipitation-hardening stainless steel

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Nelson, E. E.

    1970-01-01

    Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure.

  9. Role(s) of pretreatment, inhibitors, and other process steps that effect surface composition on the under-paint corrosion of an aluminum-copper-magnesium alloy 2024-T3

    NASA Astrophysics Data System (ADS)

    Little, Daryl A.

    2006-12-01

    Under-paint corrosion is a surface corrosion that grows under a coating. The composition of an aluminum alloy, particularly Cu and Fe content, has a direct and dominant effect on the growth rate of filiform corrosion (FFC) and scribe-creep. The Cu and Fe content leads to formation of galvanic cells between intermetallic compounds (IMCs) or replated Cu and the aluminum-rich matrix. However, there is no model which describes scribe-creep behavior and can be used to predict the effect of material and surface pretreatment parameters such as inhibitors, chemical surface pretreatment, and alloy microstructure. Surface pretreatments and aging which control the amount of surface copper and alter IMC distributions decrease the growth rate of scribe-creep. Scribe-creep was observed to be enhanced by temperature, regardless of surface pretreatment, as well as by artificial aging and surface pretreatments. Scribe-creep was accelerated by pretreatments that increased surface copper or left a high capacity for Cu-replating such as Cu-containing IMCs. Pretreatment was rationalized to decrease the cathodic oxygen reduction reaction (ORR) rate, which supports anodic undercutting at the head of the corrosion front. In this galvanic corrosion mechanism, the scribe-creep rate will be proportional to the rate of the anodic dissolution at the head. This, in turn, is proportional to the galvanic corrosion rate. Both charge transfer controlled and mass transport controlled cathodic reaction rates occurred at the fastest rates at the scratch and tail. The charge transfer controlled cathodic reaction rate was directly proportional to the surface coverage of Cu (thetaCu) while the mass transport limited rate was a complex nonlinear function of thetaCu . Based on enhanced understanding a galvanic couple model that describes scribe-creep rates in terms of the relevant processes at the tail and head as well as ohmic voltage between the head and tail was developed in order to explain scribe

  10. Corrosive wear principles

    SciTech Connect

    Schumacher, W.J.

    1993-12-31

    The dual effects of corrosion and wear operate together in such industries as paper and pulp, coal handling, mining, and sugar beet extraction. There is a synergistic effect that causes far greater wastage to carbon steels, alloy steels, and even much more abrasion resistant cast irons. Several laboratory and in situ studies have been conducted to better understand the contributions of corrosion and wear to the wastage process. The environmental conditions are usually set by the process. However, there are a few instances where inhibitors as sodium nitrite, sodium chromate, and sodium metasilicate have been successfully used to reduce metal wastage of carbon steels. Hardness has been found to be an unreliable guide to performance under wet sliding conditions. Heat treated alloy steels and cast irons are inferior to stainless steels. Even distilled water is too severe a corrodent for steels. While the austenitic stainlesses perform the best, cold rolling to increase hardness does not further improve their performance. The surface roughness of stainless steels gets smoother during corrosive wear testing while it gets rougher for the alloy steels. This observation substantiated the reputation of improved slideability for stainless alloys over alloy steels.

  11. Corrosion of stainless steel during acetate production

    SciTech Connect

    Qi, J.S.; Lester, G.C.

    1996-07-01

    Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

  12. Aqueous alteration in CR chondrites: Meteorite parent body processes as analogue for long-term corrosion processes relevant for nuclear waste disposal

    NASA Astrophysics Data System (ADS)

    Morlok, Andreas; Libourel, Guy

    2013-02-01

    Aqueous alteration of carbonaceous chondrites is one of the fundamental processes on accreting planetesimals that changes pristine materials from the formation of the Solar System. The study of mineralogical, petrological and chemical changes resulting from this alteration provides insight into the physical and chemical setting of forming planetesimals. CR chondrites provide samples for all stages of aqueous alteration, from type 3 to 1 (entirely hydrated), and are thus suited to study the alteration of pristine materials in a coherent sequence. Vitrification is a common way to store and stabilize fission products and minor actinides resulting from the reprocessing of nuclear spent fuel in a nuclear boro-silica glass in steel containers. The waste material has to be stored safely for a period of at least 105-106 years in a clay-rich geological repository. Laboratory experiments being too short to follow the long-term evolution of these materials, we analyzed the mineralogical, petrological and chemical changes in a series of CR chondrites (Renazzo CR2, Al Rais CR2, and GRO 95577 CR1) to serve as analogues. Rims of secondary materials around metal grains in contact to the fine-grained matrix serve as analogue to the interface between steel containment and the surrounding clay-rich geological layer, while chondrule glassy mesostasis is used as a proxy of the nuclear glass. With increasing degree of aqueous alteration in the sequence, Renazzo → Al Rais → GRO 95577, the size of the rims increase. Fe-rich alteration rims are ˜10 μm in thickness around metal grains in the fine-grained matrix in Renazzo. In Al Rais, multi-layered structures of interchanging Fe, S and P/Ca-rich layers appear, with a thickness of up to ˜30 μm. In the highly altered GRO 95577, extensive inner and external rims of secondary phases reach up to ˜200 μm into the surrounding matrix. In chondrules, metal in contact with the altered mesostasis shows similar trends, but with thinner

  13. Mechanism of hot corrosion of IN-738

    NASA Technical Reports Server (NTRS)

    Meier, G. H.

    1982-01-01

    The Na2SO4 - induced hot corrosion of IN-738 in the temperature range 900 C to 1000 C is characterized by an initiation stage during which the corrosion rate is slow followed by a propagation stage during which the corrosion rate is markedly accelerated. In the second stage, corrosion is accelerated due essentially to a sulfidation/oxidation mechanism; in the third stage, the rate becomes catastrophic due to acid fluxing induced by an accumulation of refractory metal oxides (particularly MoO3) in the Na2SO4. The sequential stages in the corrosion process are described and a mechanism proposed. The influence of alloy microstructure on the corrosion mechanism is also discussed.

  14. Failure Prevention by Short Time Corrosion Tests

    SciTech Connect

    MICKALONIS, JOHN

    2005-05-01

    Short time corrosion testing of perforated sheets and wire meshes fabricated from Type 304L stainless steel, Alloy 600 and C276 showed that 304L stainless steel perforated sheet should perform well as the material of construction for dissolver baskets. The baskets will be exposed to hot nitric acid solutions and are limited life components. The corrosion rates of the other alloys and of wire meshes were too high for useful extended service. Test results also indicated that corrosion of the dissolver should drop quickly during the dissolutions due to the inhibiting effects of the corrosion products produced by the dissolution processes.

  15. Feasibility Study of Low Force Robotic Friction Stir Process and its Effect On Cavitation Erosion and Electrochemical Corrosion for Ni Al Bronze Alloys

    NASA Astrophysics Data System (ADS)

    Ahmad, Azman; Li, Huijun; Pan, Zengxi; Cuiuri, Dominic; van Duin, Stephen; Larkin, Nathan; Polden, Joseph; Lane, Nathan

    2014-12-01

    Robotic friction stir processing (FSP) has not been widely researched to date. This is perhaps due to the limited force capabilities of industrial robots in comparison with dedicated commercial FSP equipment. When operating a FSP machine, the force used to plunge the tools may range from 5000 to 8000 N which is currently beyond the capability of most robots. However, the capacity of robotic manipulators is increasing, so low force friction stir processing is becoming feasible. The ability of the robot arm to apply a controlled force that is normal to a 3-dimensional surface without the need to reorient the workpiece makes it a very useful tool for FSP of complex components. In this analysis, a robot arm with a capacity of 2500 N is used to improve the surface properties of nickel aluminum bronze (NAB) using low force FSP. Multiple passes were applied to the surface of the test sample for a more consistent spread of the stir zone. The sample was then microhardness tested and demonstrated a 62 pct increase in surface hardness. Cavitation erosion testing of the original and processed surfaces was also performed as per ASTM G-32. The erosion rate of the processed NAB sample was 44 pct of the rate experienced by the original cast NAB sample. Finally, the corrosion potentials of FSP NAB were measured at 45 mV less anodic than the unprocessed material, indicating that the processed material is more noble relative to the cast NAB sample.

  16. The Corrosion and Corrosion Fatigue Behavior of Nickel Based Alloy Weld Overlay and Coextruded Claddings

    NASA Astrophysics Data System (ADS)

    Stockdale, Andrew

    The use of low NOx boilers in coal fired power plants has resulted in sulfidizing corrosive conditions within the boilers and a reduction in the service lifetime of the waterwall tubes. As a solution to this problem, Ni-based weld overlays are used to provide the necessary corrosion resistance however; they are susceptible to corrosion fatigue. There are several metallurgical factors which give rise to corrosion fatigue that are associated with the localized melting and solidification of the weld overlay process. Coextruded coatings offer the potential for improved corrosion fatigue resistance since coextrusion is a solid state coating process. The corrosion and corrosion fatigue behavior of alloy 622 weld overlays and coextruded claddings was investigated using a Gleeble thermo-mechanical simulator retrofitted with a retort. The experiments were conducted at a constant temperature of 600°C using a simulated combustion gas of N2-10%CO-5%CO2-0.12%H 2S. An alternating stress profile was used with a minimum tensile stress of 0 MPa and a maximum tensile stress of 300 MPa (ten minute fatigue cycles). The results have demonstrated that the Gleeble can be used to successfully simulate the known corrosion fatigue cracking mechanism of Ni-based weld overlays in service. Multilayer corrosion scales developed on each of the claddings that consisted of inner and outer corrosion layers. The scales formed by the outward diffusion of cations and the inward diffusion of sulfur and oxygen anions. The corrosion fatigue behavior was influenced by the surface finish and the crack interactions. The initiation of a large number of corrosion fatigue cracks was not necessarily detrimental to the corrosion fatigue resistance. Finally, the as-received coextruded cladding exhibited the best corrosion fatigue resistance.

  17. Corrosion probe. Innovative technology summary report

    SciTech Connect

    1999-05-01

    Over 253 million liters of high-level waste (HLW) generated from plutonium production is stored in mild steel tanks at the Department of Energy (DOE) Hanford Site. Corrosion monitoring of double-shell storage tanks (DSTs) is currently performed at Hanford using a combination of process knowledge and tank waste sampling and analysis. Available technologies for corrosion monitoring have progressed to a point where it is feasible to monitor and control corrosion by on-line monitoring of the corrosion process and direct addition of corrosion inhibitors. The electrochemical noise (EN) technique deploys EN-based corrosion monitoring probes into storage tanks. This system is specifically designed to measure corrosion rates and detect changes in waste chemistry that trigger the onset of pitting and cracking. These on-line probes can determine whether additional corrosion inhibitor is required and, if so, provide information on an effective end point to the corrosion inhibitor addition procedure. This report describes the technology, its performance, its application, costs, regulatory and policy issues, and lessons learned.

  18. Wear and Corrosion Behaviors of FeCrBSiNbW Amorphous/Nanocrystalline Coating Prepared by Arc Spraying Process

    NASA Astrophysics Data System (ADS)

    Cheng, J. B.; Wang, Z. H.; Xu, B. S.

    2012-09-01

    FeCrBSiNbW coatings were synthesized using robotically manipulating twin wires arc spraying system. The microstructure and mechanical properties of the coating were characterized. The coating has a laminated structure, and its porosity is 2.8%. The microstructure of the coating consists of amorphous and α-(Fe,Cr) nanocrystalline. The nanocrystalline grains with a scale of 20-75 nm are homogenously dispersed in amorphous matrix. The results show that FeCrBSiNbW coating has excellent wear and corrosion resistance. The wear resistance of the coating is about 4.6 times higher than that of 3Cr13 coating under the same testing condition. In 3.5% NaCl aqueous solution, the amorphous/nanocrystalline coating presents lower I corr values in polarization curves and higher fitted R t values in EIS plots than that of the 0Cr18Ni9 coating (chemical composition by EDAX analysis: C1.07-O12.38-Si0.49-Cr15.18-Mn0.89-Ni7.09-Fe62.24 at.%).

  19. Microbiologically influenced corrosion in wastewater treatment plants

    SciTech Connect

    Soebbing, J.B.; Yolo, R.A.

    1996-09-01

    Microbiologically influenced corrosion (MIC) activity in wastewater treatment plans is discussed. Three case histories are presented showing throughwall pitting from MIC in recycle activated sludge process piping systems. Field and laboratory investigation activities are reported. Alternatives are reviewed for corrosion prevention and mitigation.

  20. Chemical processes involved in the initiation of hot corrosion of B-1900 and NASA-TRW VIA. [high temperature tests of superalloys

    NASA Technical Reports Server (NTRS)

    Fryburg, G. C.; Kohl, F. J.; Stearns, C. A.

    1979-01-01

    Sodium surface-induced hot corrosion of B-1900 and NASA-TRW VIA alloys at 900 C has been studied, with special attention to the chemical reactions during and immediately after the induction period. Thermogravimetric tests were run and data were obtained by chemical analysis of water soluble metal salts and of residual sulfate. Surface analyses of hot corroded samples were obtained by spectroscopic techniques (ESCA). A chemical mechanism for elucidating Na2SO4-induced hot corrosion is proposed indicating that hot corrosion is initiated by basic fluxing of the protective Al2O3 scale. The sequential, catastrophic corrosion results from molybdenum content. The self-sustaining feature is a consequence of the cyclic nature of the acidic fluxing. It is believed that the mechanism is applicable not only to laboratory results, but also to the practical problem of hot corrosion encountered in gas turbine engines.

  1. Predicting concrete corrosion of sewers using artificial neural network.

    PubMed

    Jiang, Guangming; Keller, Jurg; Bond, Philip L; Yuan, Zhiguo

    2016-04-01

    Corrosion is often a major failure mechanism for concrete sewers and under such circumstances the sewer service life is largely determined by the progression of microbially induced concrete corrosion. The modelling of sewer processes has become possible due to the improved understanding of in-sewer transformation. Recent systematic studies about the correlation between the corrosion processes and sewer environment factors should be utilized to improve the prediction capability of service life by sewer models. This paper presents an artificial neural network (ANN)-based approach for modelling the concrete corrosion processes in sewers. The approach included predicting the time for the corrosion to initiate and then predicting the corrosion rate after the initiation period. The ANN model was trained and validated with long-term (4.5 years) corrosion data obtained in laboratory corrosion chambers, and further verified with field measurements in real sewers across Australia. The trained model estimated the corrosion initiation time and corrosion rates very close to those measured in Australian sewers. The ANN model performed better than a multiple regression model also developed on the same dataset. Additionally, the ANN model can serve as a prediction framework for sewer service life, which can be progressively improved and expanded by including corrosion rates measured in different sewer conditions. Furthermore, the proposed methodology holds promise to facilitate the construction of analytical models associated with corrosion processes of concrete sewers. PMID:26841228

  2. EFFECT OF CREVICE FORMER ON CORROSION DAMAGE PROPAGATION

    SciTech Connect

    J.H. Payer; U. Landau; X. Shan; A.S. Agarwal

    2006-03-01

    The objectives of this report are: (1) To determine the effect of the crevice former on the localized corrosion damage propagation; (2) FOCUS on post initiation stage, crevice propagation and arrest processes; (3) Determine the evolution of damage--severity, shape, location/distribution, damage profile; and (4) Model of crevice corrosion propagation, i.e. the evolution of the crevice corrosion damage profile.

  3. Predicting concrete corrosion of sewers using artificial neural network.

    PubMed

    Jiang, Guangming; Keller, Jurg; Bond, Philip L; Yuan, Zhiguo

    2016-04-01

    Corrosion is often a major failure mechanism for concrete sewers and under such circumstances the sewer service life is largely determined by the progression of microbially induced concrete corrosion. The modelling of sewer processes has become possible due to the improved understanding of in-sewer transformation. Recent systematic studies about the correlation between the corrosion processes and sewer environment factors should be utilized to improve the prediction capability of service life by sewer models. This paper presents an artificial neural network (ANN)-based approach for modelling the concrete corrosion processes in sewers. The approach included predicting the time for the corrosion to initiate and then predicting the corrosion rate after the initiation period. The ANN model was trained and validated with long-term (4.5 years) corrosion data obtained in laboratory corrosion chambers, and further verified with field measurements in real sewers across Australia. The trained model estimated the corrosion initiation time and corrosion rates very close to those measured in Australian sewers. The ANN model performed better than a multiple regression model also developed on the same dataset. Additionally, the ANN model can serve as a prediction framework for sewer service life, which can be progressively improved and expanded by including corrosion rates measured in different sewer conditions. Furthermore, the proposed methodology holds promise to facilitate the construction of analytical models associated with corrosion processes of concrete sewers.

  4. High temperature electrochemical corrosion rate probes

    SciTech Connect

    Bullard, Sophie J.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Ziomek-Moroz, M.

    2005-09-01

    Corrosion occurs in the high temperature sections of energy production plants due to a number of factors: ash deposition, coal composition, thermal gradients, and low NOx conditions, among others. Electrochemical corrosion rate (ECR) probes have been shown to operate in high temperature gaseous environments that are similar to those found in fossil fuel combustors. ECR probes are rarely used in energy production plants at the present time, but if they were more fully understood, corrosion could become a process variable at the control of plant operators. Research is being conducted to understand the nature of these probes. Factors being considered are values selected for the Stern-Geary constant, the effect of internal corrosion, and the presence of conductive corrosion scales and ash deposits. The nature of ECR probes will be explored in a number of different atmospheres and with different electrolytes (ash and corrosion product). Corrosion rates measured using an electrochemical multi-technique capabilities instrument will be compared to those measured using the linear polarization resistance (LPR) technique. In future experiments, electrochemical corrosion rates will be compared to penetration corrosion rates determined using optical profilometry measurements.

  5. Superconductivity in Ba(Pb,Bi,Sb)O 3, Ba(Pb,Bi,Te)O 3 and (Ba,La) (Pb,Bi,Tl)O 3 systems

    NASA Astrophysics Data System (ADS)

    Nagarajan, R.; Vasanthacharya, N. Y.; Gopalakrishnan, J.; Rao, C. N. R.

    1991-02-01

    It is possible to substitute Bi in the superconducting BaPb 0.75Bi 0.25O 3 by Sb or Te without destroying the superconductivity. With Sb, a continuous series of solid solutions BaPb 0.75Bi 0.25-ySb yO 3 (0 ⩽ y ⩽ 0.25) exists, while with Te, perovskite BaPb 0.75Bi 0.25-yTe yO 3 exists only upto y = 0.15. With increasing substitution by Sb or Te, T c decreases continously in both the systems. Superconductivity with a maximum T c of 8K is found in Ba 0.9La 0.1Pb 0.9-yBi yTl 0.1O 3 for y = 0.25.

  6. Internal Corrosion and Deposition Control

    EPA Science Inventory

    This chapter reviews the current knowledge of the science of corrosion control and control of scaling in drinking water systems. Topics covered include: types of corrosion; physical, microbial and chemical factors influencing corrosion; corrosion of specific materials; direct ...

  7. General Corrosion and Localized Corrosion of the Drip Shield

    SciTech Connect

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  8. Corrosion of Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Jacobson, Nathan S.

    1999-01-01

    Non-oxide ceramics are promising materials for a range of high temperature applications. Selected current and future applications are listed. In all such applications, the ceramics are exposed to high temperature gases. Therefore it is critical to understand the response of these materials to their environment. The variables to be considered here include both the type of ceramic and the environment to which it is exposed. Non-oxide ceramics include borides, nitrides, and carbides. Most high temperature corrosion environments contain oxygen and hence the emphasis of this chapter will be on oxidation processes.

  9. Effect of chemical etching and aging in boiling water on the corrosion resistance of Nitinol wires with black oxide resulting from manufacturing process.

    PubMed

    Shabalovskaya, S; Rondelli, G; Anderegg, J; Simpson, B; Budko, S

    2003-07-15

    The effect of chemical etching in a HF/HNO(3) acid solution and aging in boiling water on the corrosion resistance of Nitinol wires with black oxide has been evaluated with the use of potentiodynamic, modified potentiostatic ASTM F746, and scratch tests. Scanning-electron microscopy, elemental XPS, and Auger analysis were employed to characterize surface alterations induced by surface treatment and corrosion testing. The effect of aging in boiling water on the temperatures of martensitic transformations and shape recovery was evaluated by means of measuring the wire electroresistance. After corrosion tests, as-received wires revealed uniformly cracked surfaces reminiscent of the stress-corrosion-cracking phenomenon. These wires exhibited negative breakdown potentials in potentiostatic tests and variable breakdown potentials in potentiodynamic tests (- 100 mV to + 400 mV versus SCE). Wires with treated surfaces did not reveal cracking or other traces of corrosion attacks in potentiodynamic tests up to + 900-1400-mV potentials and no pitting after stimulation at + 800 mV in potentiostatic tests. They exhibited corrosion behavior satisfactory for medical applications. Significant improvement of corrosion parameters was observed on the reverse scans in potentiodynamic tests after exposure of treated wires to potentials > 1000 mV. In scratch tests, the prepared surfaces repassivated only at low potentials, comparable to that of stainless steel. Tremendous improvement of the corrosion behavior of treated Nitinol wires is associated with the removal of defect surface material and the growth of stable TiO(2) oxide. The role of precipitates in the corrosion resistance of Nitinol-scratch repassivation capacity in particular-is emphasized in the discussion.

  10. The Proposed Yucca Mountain Repository From A Corrosion Perspective

    SciTech Connect

    J.H. Payer

    2005-03-10

    Corrosion is a primary determinant of waste package performance at the proposed Yucca Mountain Repository and will control the delay time for radionuclide transport from the waste package. Corrosion is the most probable and most likely degradation process that will determine when packages will be penetrated and the shape size and distribution of those penetrations. The general issues in corrosion science, materials science and electrochemistry are well defined, and the knowledge base is substantial for understanding corrosion processes. In this paper, the Yucca Mountain Repository is viewed from a corrosion perspective.

  11. Microvasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor) eye: a scanning electron microscopic study of corrosion casts.

    PubMed

    Ninomiya, Hiroyoshi; Inomata, Tomo; Kanemaki, Nobuyuki

    2005-06-01

    We have studied the vasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor), a nocturnal mammal, using light and scanning electron microscopic examination of corrosion casts. We carried out an identical study in the crab-eating macaque (Macaca fascicularis), which forages only during the daytime, in order to compare the ocular vasculature with that of nocturnal mammals. Our observations in raccoons demonstrated a photoreceptor layer associated with rich lymph and a poorly vascularized retina. The meridian region of the eye, which lies in the horizontal plane and pass around the optic disc, had a markedly sparse capillary network. This horizontal sparse vascular band may correspond to a visual streak. Ciliary process capillaries were delicate, and formed a well-developed and compact network. Choriocapillaries were quite thin and formed a coarse capillary network. This contrasted with the dense retinal and well-extended choroidal capillary networks noted in the macaques. Our findings suggest that the sparse retinal capillary network in raccoons is extremely beneficial for photon capture, thereby allowing the raccoon to see well at night, as the retinal vessels restrict the inflow of photons toward the photoreceptors. The well-developed lymph probably compensates for the sparse retinal capillaries and choriocapillaries and nourishes the retina in the nocturnal raccoon.

  12. Corrosion performance of structural alloys.

    SciTech Connect

    Natesan, K.

    1999-07-15

    Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.

  13. Microbiologically influenced corrosion in wastewater treatment plants

    SciTech Connect

    Soebbing, J.B.; Yolo, R.A.

    1995-12-01

    Microbiologically influenced corrosion (MIC) activity in wastewater treatment plants is discussed. Three case histories are presented showing through-wall pitting from MIC in return activated sludge (RAS) process piping systems. Field and laboratory investigation activities are reported. Alternatives are reviewed for initial corrosion prevention and mitigation following identification. A brief discussion of wastewater treatment and specifically, the activated sludge process is also provided. The applicability of common MIC prevention and mitigation practices to wastewater treatment facilities or processes is also reviewed.

  14. Stress corrosion and hydrogen embrittlement

    NASA Technical Reports Server (NTRS)

    Blackburn, M. J.; Smyrl, W. H.

    1973-01-01

    Service experience applications, experimental data generation, and the development of satisfactory quantitative theories relevant to the suppression and control of stress corrosion cracking in titanium are discussed. The impact of stress corrosion cracking (SCC) on the use of titanium alloys is considered, with emphasis on utilization in the aerospace field. Recent data on hot salt SCC, crack growth in hydrogen gas, and crack growth in liquid environments containing halide ions are reviewed. The status of the understanding of crack growth processes in these environments is also examined.

  15. Hot corrosion of the B2 nickel aluminides

    NASA Technical Reports Server (NTRS)

    Ellis, David L.

    1993-01-01

    The hot corrosion behavior of the B2 nickel aluminides was studied to determine the inherent hot corrosion resistance of the beta nickel aluminides and to develop a mechanism for the hot corrosion of the beta nickel aluminides. The effects of the prior processing of the material, small additions of zirconium, stoichiometry of the materials, and preoxidation of the samples were also examined. Additions of 2, 5, and 15 w/o chromium were used to determine the effect of chromium on the hot corrosion of the beta nickel aluminides and the minimum amount of chromium necessary for good hot corrosion resistance. The results indicate that the beta nickel aluminides have inferior inherent hot corrosion resistance despite their excellent oxidation resistance. Prior processing and zirconium additions had no discernible effect on the hot corrosion resistance of the alloys. Preoxidation extended the incubation period of the alloys only a few hours and was not considered to be an effective means of stopping hot corrosion. Stoichiometry was a major factor in determining the hot corrosion resistance of the alloys with the higher aluminum alloys having a definitely superior hot corrosion resistance. The addition of chromium to the alloys stopped the hot corrosion attack in the alloys tested. From a variety of experimental results, a complex hot corrosion mechanism was proposed. During the early stages of the hot corrosion of these alloys the corrosion is dominated by a local sulphidation/oxidation form of attack. During the intermediate stages of the hot corrosion, the aluminum depletion at the surface leads to a change in the oxidation mechanism from a protective external alumina layer to a mixed nickel-aluminum spinel and nickel oxide that can occur both externally and internally. The material undergoes extensive cracking during the later portions of the hot corrosion.

  16. Corrosion probes for fireside monitoring in coal-fired boilers

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Holcomb, Gordon R.

    2005-01-01

    Corrosion probes are being developed and combined with an existing measurement technology to provide a tool for assessing the extent of corrosion of metallic materials on the fireside in coal-fired boilers. The successful development of this technology will provide power plant operators the ability to (1) accurately monitor metal loss in critical regions of the boiler, such as waterwalls, superheaters, and reheaters; and (2) use corrosion rates as process variables. In the former, corrosion data could be used to schedule maintenance periods and in the later, processes can be altered to decrease corrosion rates. The research approach involves laboratory research in simulated environments that will lead to field tests of corrosion probes in coal-fired boilers. Laboratory research has already shown that electrochemically-measured corrosion rates for ash-covered metals are similar to actual mass loss corrosion rates. Electrochemical tests conducted using a potentiostat show the corrosion reaction of ash-covered probes at 500?C to be electrochemical in nature. Corrosion rates measured are similar to those from an automated corrosion monitoring system. Tests of corrosion probes made with mild steel, 304L stainless steel (SS), and 316L SS sensors showed that corrosion of the sensors in a very aggressive incinerator ash was controlled by the ash and not by the alloy content. Corrosion rates in nitrogen atmospheres tended to decrease slowly with time. The addition of oxygen-containing gases, oxygen and carbon dioxide to nitrogen caused a more rapid decrease in corrosion rate, while the addition of water vapor increased the corrosion rate.

  17. Corrosion inhibiting organic coatings

    SciTech Connect

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  18. Duralumin and Its Corrosion

    NASA Technical Reports Server (NTRS)

    Nelson, WM

    1927-01-01

    The types of corrosion and factors of corrosion of duralumin are investigated. Salt water is the most common of the corroding media with which designers have to contend in using duralumin in aircraft and ships.

  19. Surface modification for corrosion resistance

    SciTech Connect

    Natesan, K.

    1993-06-01

    The raw gas environments that arise from coal gasification have chemical compositions that are low in pO{sub 2} and moderate-to-high in pS{sub 2}. Metallic materials for service in such an environment undergo predominantly sulfidation attack at temperatures of 400 to 700{degree}C. Modification of alloy compositions in bulk can alter the scaling processes and lead to improvements in corrosion resistance, but the benefits can only be attained at temperatures much higher than the service temperatures of the components. Modification of surfaces of structural components by several of the coating techniques examined in this study showed substantial benefit in corrosion resistance when tested in simulated coal gasification environments. The paper presents several examples of surface modification and their corrosion performance.

  20. Corrosion inhibition for distillation apparatus

    DOEpatents

    Baumert, Kenneth L.; Sagues, Alberto A.; Davis, Burtron H.; Schweighardt, Frank K.

    1985-01-01

    Tower material corrosion in an atmospheric or sub-atmospheric distillation tower in a coal liquefaction process is reduced or eliminated by subjecting chloride-containing tray contents to an appropriate ion-exchange resin to remove chloride from such tray contents materials.

  1. Novel Corrosion Sensor for Vision 21 Systems

    SciTech Connect

    Heng Ban; Bharat Soni

    2007-03-31

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall goal of this project is to develop a technology for on-line fireside corrosion monitoring. This objective is achieved by the laboratory development of sensors and instrumentation, testing them in a laboratory muffle furnace, and eventually testing the system in a coal-fired furnace. This project successfully developed two types of sensors and measurement systems, and successful tested them in a muffle furnace in the laboratory. The capacitance sensor had a high fabrication cost and might be more appropriate in other applications. The low-cost resistance sensor was tested in a power plant burning eastern bituminous coals. The results show that the fireside corrosion measurement system can be used to determine the corrosion rate at waterwall and superheater locations. Electron microscope analysis of the corroded sensor surface provided detailed picture of the corrosion process.

  2. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    SciTech Connect

    Daniel Tao; Craig A. Blue

    2006-07-20

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, novel surface treatment technologies, High Density Infrared (HDI) and Laser Surface Engineering (LSE) surface coating processes were developed for the surface enhancement of selected mineral processing equipment. Microstructural and mechanical properties of the coated specimens were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of ASTM A36 (raw coal screen section) and can be significantly increased by applying HDI and LSE coating processes. Field testing has been performed using a LSE-treated screen panel and it showed a 2 times improvement of the service life.

  3. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    SciTech Connect

    Daniel Tao; Craig A. Blue

    2004-08-01

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, wear problems of mineral processing equipment including screens, sieve bends, heavy media vessel, dewatering centrifuge, etc., were identified. A novel surface treatment technology, high density infrared (HDI) surface coating process was proposed for the surface enhancement of selected mineral processing equipment. Microstructural and mechanical properties of the coated samples were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of AISI 4140 and ASTM A36 steels can be increased 3 and 5 folds, respectively by the application of HDI coatings.

  4. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    SciTech Connect

    Daniel Tao; R. Honaker; B. K. Parekh

    2007-09-20

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, novel surface treatment technologies, High Density Infrared (HDI) and Laser Surface Engineering (LSE) surface coating processes were developed for the surface enhancement of selected mineral and coal processing equipment. Microstructural and mechanical properties of the coated specimens were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of ASTM A36 (raw coal screen section) and can be significantly increased by applying HDI and LSE coating processes. Field testing has been performed using a LSE-treated screen panel and it showed a significant improvement of the service life.

  5. Development of Advanced Surface Enhancement Technology for Decreasing Wear and Corrosion of Equipment Used for Mineral Processing

    SciTech Connect

    Daniel Tao; Craig A. Blue

    2005-08-01

    Equipment wear is a major concern in the mineral processing industry, which dramatically increases the maintenance cost and adversely affects plant operation efficiency. In this research, a novel surface treatment technology, laser surface engineering (LSE) surface coating process was proposed for the surface enhancement of selected mineral processing equipment. Microstructural and mechanical properties of the coated specimen were characterized. Laboratory-simulated wear tests were conducted to evaluate the tribological performance of the coated components. Test results indicate that the wear resistance of ASTM A36 (raw coal screen section) and AISI 4140 steels can be increased 10 and 25 folds, respectively by the application of LSE process. Initial field testing showed a 2 times improvement of the service life of a raw coal screen panel.

  6. Laser-controllable coatings for corrosion protection.

    PubMed

    Skorb, Ekaterina V; Skirtach, Andre G; Sviridov, Dmitry V; Shchukin, Dmitry G; Möhwald, Helmuth

    2009-07-28

    We introduce a novel and versatile approach to the corrosion protection by use of "smart" laser-controllable coating. The main advantage of the proposed technique is that one could terminate the corrosion process by very intensive healing after an appearance of corrosion centers using local laser irradiation. It is also shown that by applying a polyelectrolyte shell with noble metal particles over the mesoporous titania and silica via layer-by-layer assembly it is possible to fabricate micro- and nanoscaled reservoirs, which, being incorporated into the zirconia-organosilica matrix, are responsible for the ability of laser-driven release of the loaded materials (e.g., corrosion inhibitor). Furthermore, the resultant films are highly adhesive and could be easily deposited onto different metallic substrates. Laser-mediated remote release of incorporated corrosion inhibitor (benzotriazole) from engineered mesoporous containers with silver nanoparticles in the container shell is observed in real time on single and multicontainer levels.

  7. Corrosion problems with aqueous coolants, final report

    SciTech Connect

    Diegle, R B; Beavers, J A; Clifford, J E

    1980-04-11

    The results of a one year program to characterize corrosion of solar collector alloys in aqueous heat-transfer media are summarized. The program involved a literature review and a laboratory investigation of corrosion in uninhibited solutions. It consisted of three separate tasks, as follows: review of the state-of-the-art of solar collector corrosion processes; study of corrosion in multimetallic systems; and determination of interaction between different waters and chemical antifreeze additives. Task 1 involved a comprehensive review of published literature concerning corrosion under solar collector operating conditions. The reivew also incorporated data from related technologies, specifically, from research performed on automotive cooling systems, cooling towers, and heat exchangers. Task 2 consisted of determining the corrosion behavior of candidate alloys of construction for solar collectors in different types of aqueous coolants containing various concentrations of corrosive ionic species. Task 3 involved measuring the degradation rates of glycol-based heat-transfer media, and also evaluating the effects of degradation on the corrosion behavior of metallic collector materials.

  8. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  9. Electrochemical situation in corrosion-mechanical cracks

    SciTech Connect

    Petrov, L.N.; Kalinkov, A.Yu.

    1995-01-01

    It is shown that the electrochemical situation in corrosion cracks is determined by the electromotive force of local galvanic cells at the crack tip and the polarization resistance of anodic processes.

  10. Minimizing corrosion in coal liquid distillation

    DOEpatents

    Baumert, Kenneth L.; Sagues, Alberto A.; Davis, Burtron H.

    1985-01-01

    In an atmospheric distillation tower of a coal liquefaction process, tower materials corrosion is reduced or eliminated by introduction of boiling point differentiated streams to boiling point differentiated tower regions.

  11. Launch Pad Coatings for Smart Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Bucherl, Cori N.; Li, Wenyan; Buhrow, Jerry W.; Curran, Jerome P.; Whitten, Mary C.

    2010-01-01

    Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability

  12. Events as Power Source: Wireless Sustainable Corrosion Monitoring

    PubMed Central

    Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

    2013-01-01

    This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf) energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS. PMID:24351643

  13. Events as power source: wireless sustainable corrosion monitoring.

    PubMed

    Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

    2013-12-17

    This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf) energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

  14. High-temperature corrosion: Issues in alloy selection

    NASA Astrophysics Data System (ADS)

    Lai, George Y.

    1991-11-01

    This article examines the modes of high-temperature corrosion that are often responsible for equipment failures in a variety of industries, including aerospace and gas turbines; heat treating; mineral and metallurgical processing; chemical processing; refining and petrochemical processing; ceramic, electronic, and glass manufacturing; automotive; pulp and paper; waste incineration; and power generation and energy conversion. Corrosion data related to each corrosion mode are reviewed to provide readers with a brief materials selection guide.

  15. A Multifunctional Smart Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Buhrow, Jerry W.; Jolley, Scott T.

    2012-01-01

    Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on micro-encapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy. This

  16. IN DRIFT CORROSION PRODUCTS

    SciTech Connect

    D.M. Jolley

    1999-12-02

    As directed by a written development plan (CRWMS M&O 1999a), a conceptual model for steel and corrosion products in the engineered barrier system (EBS) is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE) Revision 2 (NRC 1999). This document provides the conceptual framework for the in-drift corrosion products sub-model to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. However, the concepts discussed within this report may also apply to some near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts.

  17. Tribological and corrosion behavior of friction stir processed Ti-CaP nanocomposites in simulated body fluid solution.

    PubMed

    Farnoush, Hamidreza; Abdi Bastami, Ashkan; Sadeghi, Ali; Aghazadeh Mohandesi, Jamshid; Moztarzadeh, Fathollah

    2013-04-01

    In the present study, friction stir processing was utilized to incorporate nano-hydroxyapatite particles into Ti-6Al-4V substrates to fabricate Ti-CaP nanocomposite surface layer. Microstructures of the stir zone and the fabricated Ti-CaP nanocomposite layer were analyzed using optical and scanning electron microscopy, respectively. Microhardness profile and AFM analysis of substrates were then studied. The microhardness of Ti-CaP nanocomposite layer was reached about 386 HV due to the grain refinement and the distribution of nano-hydroxyapatite particles. Potentiodynamic polarization studies showed that the Ti-CaP nanocomposite layer protected effectively the Ti-6Al-4V substrates from corroding in simulated body fluid solution. The tribological properties of the samples were studied in both dry and simulated biological conditions. The wear rate and friction coefficient decreased by friction stir processing on Ti-6Al-4V substrates. From the analysis of plotted graphs of weight loss versus sliding distance, a correlation between wear coefficient and microhardness through thickness was established. The wear mechanisms were also investigated through scanning electron microscopy. It was shown that the major mechanism was abrasive wear.

  18. Sequential growth of zinc oxide nanorod arrays at room temperature via a corrosion process: application in visible light photocatalysis.

    PubMed

    Iqbal, Danish; Kostka, Aleksander; Bashir, Asif; Sarfraz, Adnan; Chen, Ying; Wieck, Andreas D; Erbe, Andreas

    2014-11-12

    Many photocatalyst systems catalyze chemical reactions under ultraviolet (UV) illumination, because of its high photon energies. Activating inexpensive, widely available materials as photocatalyst using the intense visible part of the solar spectrum is more challenging. Here, nanorod arrays of the wide-band-gap semiconductor zinc oxide have been shown to act as photocatalysts for the aerobic photo-oxidation of organic dye Methyl Orange under illumination with red light, which is normally accessible only to narrow-band semiconductors. The homogeneous, 800-1000-nm-thick ZnO nanorod arrays show substantial light absorption (absorbances >1) throughout the visible spectral range. This absorption is caused by defect levels inside the band gap. Multiple scattering processes by the rods make the nanorods appear black. The dominantly crystalline ZnO nanorod structures grow in the (0001) direction, i.e., with the c-axis perpendicular to the surface of polycrystalline zinc. The room-temperature preparation route relies on controlled cathodic delamination of a weakly bound polymer coating from metallic zinc, an industrially produced and cheaply available substrate. Cathodic delamination is a sequential synthesis process, because it involves the propagation of a delamination front over the base material. Consequently, arbitrarily large sample surfaces can be nanostructured using this approach.

  19. Electrochemical corrosion testing: An effective tool for corrosion inhibitor evaluation

    SciTech Connect

    Bartley, L.S.; Van de Ven, P.; Mowlem, J.K.

    1996-10-01

    Corrosivity of an Antifreeze/Coolant can lead to localized attacks which are a major cause for metal failure. To prevent this phenomenon, specific corrosion inhibitors are used to protect the different metals in service. This paper will discuss the electrochemical principles behind corrosion, Realized corrosion and corrosion inhibition. It will also discuss electrochemical techniques which allow for the evaluation of these inhibitors.

  20. Corrosion of aluminides by molten nitrate salt

    SciTech Connect

    Tortorelli, P.F.; Bishop, P.S.

    1990-01-01

    The corrosion of titanium-, iron-, and nickel-based aluminides by a highly aggressive, oxidizing NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} has been studied at 650{degree}C. It was shown that weight changes could be used to effectively evaluate corrosion behavior in the subject nitrate salt environments provided these data were combined with salt analyses and microstructural examinations. The studies indicated that the corrosion of relatively resistant aluminides by these nitrate salts proceeded by oxidation and a slow release from an aluminum-rich product layer into the salt at rates lower than that associated with many other types of metallic materials. The overall corrosion process and resulting rate depended on the particular aluminide being exposed. In order to minimize corrosion of nickel or iron aluminides, it was necessary to have aluminum concentrations in excess of 30 at. %. However, even at a concentration of 50 at. % Al, the corrosion resistance of TiAl was inferior to that of Ni{sub 3}Al and Fe{sub 3}Al. At higher aluminum concentrations, iron, nickel, and iron-nickel aluminides exhibited quite similar weight changes, indicative of the principal role of aluminum in controlling the corrosion process in NaNO{sub 3}(-KNO{sub 3})-Na{sub 2}O{sub 2} salts. 20 refs., 5 figs., 3 tabs.

  1. Nickel-base alloys combat corrosion

    SciTech Connect

    Agarwal, D.C.; Herda, W.

    1995-06-01

    The modern chemical process industry must increase production efficiency to remain competitive. Manufacturers typically meet this challenge by utilizing higher temperatures and pressures, and more-corrosive catalysts. At the same time, the industry has to solve the technical and commercial problems resulting from rigid environmental regulations. To overcome these obstacles, new alloys having higher levels of corrosion resistance have been developed. These materials are based on increased understanding of the physical metallurgy of nickel-base alloys, especially the role of alloying elements. Results of many studies have led to innovations in nickel-chromium-molybdenum alloys containing both high and low amounts of nickel. Higher molybdenum and chromium contents, together with nitrogen additions, have opened up an entirely new class of alloys having unique properties. In addition, a new chromium-base, fully wrought super stainless steel shows excellent promise in solving many corrosion problems. These newer alloys have the ability to combat uniform corrosion, localized corrosion, and stress-corrosion cracking in the harsh halogenic environment of the chemical process industry. This article briefly lists some of the major highlights and corrosion data on recent nickel-chromium-molybdenum and nickel-molybdenum alloys, and the development of a chromium-base, wrought super-austenitic alloy known as Nicrofer 3033 (Alloy 33). Some comparisons with existing alloys are presented, along with a few commercial applications.

  2. On the Problem of Stress Corrosion

    NASA Technical Reports Server (NTRS)

    Graf, L.

    1946-01-01

    The object of the present work is first to investigate accurately the processes during stress corrosion, in particular, for light metal alloys and, as the first part of the investigation, to determine its laws; and secondly to explain its causes for various alloys and thereby find means for its partial or complete elimination and thus make possible the production of light metal alloys free from any stress corrosion. In the present paper some of the results of the investigation are given and the fundamental problems of stress corrosion discussed.

  3. Electrochemical Corrosion Rate Sensors for Waste Incineration Applications

    SciTech Connect

    Covino, B.S., Jr.; Bullard, S.J.; Matthes, S.A.; Holcomb, G.R.; Ziomek-Moroz, M.; Eden, D.A.

    2007-03-01

    Electrochemical corrosion rate sensors work in high temperature waste incineration applications where ash is deposited. The ash serves as the electrolyte for electrochemical measurements, such as liner polarization resistance, electrochemical noise, and harmonic distortion analyses. Results to date have shown that these types of sensors respond qualitatively to changes in temperature, gas composition, alloy composition, and type of ash. Several years of research have shown that high temperature corrosion rate probes need to be better understood before corrosion rate can be used as a process variable by power plant operators. More recent research has shown that electrochemical corrosion probes typically measure lower corrosion rates than those measured by standard mass loss techniques. While still useful for monitoring changes in corrosion rates, absolute probe corrosion rates will need a calibration factor to be useful. Ideas for research that may help resolve these issues are presented.

  4. Thermal control system corrosion study

    NASA Technical Reports Server (NTRS)

    Yee, Robert; Folsom, Rolfe A.; Mucha, Phillip E.

    1990-01-01

    During the development of an expert system for autonomous control of the Space Station Thermal Control System (TCS), the thermal performance of the Brassboard TCS began to gradually degrade. This degradation was due to filter clogging by metallic residue. A study was initiated to determine the source of the residue and the basic cause of the corrosion. The investigation focused on the TCS design, materials compatibility, Ames operating and maintenance procedures, and chemical analysis of the residue and of the anhydrous ammonia used as the principal refrigerant. It was concluded that the corrosion mechanisms involved two processes: the reaction of water alone with large, untreated aluminum parts in a high pH environment and the presence of chlorides and chloride salts. These salts will attack the aluminum oxide layer and may enable galvanic corrosion between the aluminum and the more noble stainless steel and other metallic elements present. Recommendations are made for modifications to the system design, the materials used, and the operating and maintenance procedures, which should largely prevent the recurrence of these corrosion mechanisms.

  5. Thermal control system corrosion study

    NASA Astrophysics Data System (ADS)

    Yee, Robert; Folsom, Rolfe A.; Mucha, Phillip E.

    1990-02-01

    During the development of an expert system for autonomous control of the Space Station Thermal Control System (TCS), the thermal performance of the Brassboard TCS began to gradually degrade. This degradation was due to filter clogging by metallic residue. A study was initiated to determine the source of the residue and the basic cause of the corrosion. The investigation focused on the TCS design, materials compatibility, Ames operating and maintenance procedures, and chemical analysis of the residue and of the anhydrous ammonia used as the principal refrigerant. It was concluded that the corrosion mechanisms involved two processes: the reaction of water alone with large, untreated aluminum parts in a high pH environment and the presence of chlorides and chloride salts. These salts will attack the aluminum oxide layer and may enable galvanic corrosion between the aluminum and the more noble stainless steel and other metallic elements present. Recommendations are made for modifications to the system design, the materials used, and the operating and maintenance procedures, which should largely prevent the recurrence of these corrosion mechanisms.

  6. Silicate Glass Corrosion Mechanism revisited

    NASA Astrophysics Data System (ADS)

    Geisler, Thorsten; Lenting, Christoph; Dohmen, Lars

    2015-04-01

    Understanding the mechanism(s) of aqueous corrosion of nuclear waste borosilicate glasses is essential to predict their long-term aqueous durability in a geologic repository. Several observations have been made with compositionally different silicate glasses that cannot be explained by any of the established glass corrosion models. These models are based on diffusion-controlled ion exchange and subsequent structural reorganisation of a leached, hydrated residual glass, leaving behind a so-called gel layer. In fact, the common observation of lamellar to more complex pattern formation observed in experiment and nature, the porous structure of the corrosion layer, an atomically sharp boundary between the corrosion zone and the underlying pristine glass, as well as results of novel isotope tracer and in situ, real time experiments rather support an interface-coupled glass dissolution-silica reprecipitation model. In this model, the congruent dissolution of the glass is coupled in space and time to the precipitation and growth of amorphous silica at an inwardly moving reaction front. We suggest that these coupled processes have to be considered to realistically model the long-term performance of silicate glasses in aqueous environments.

  7. Case histories of external microbiologically influenced corrosion

    SciTech Connect

    Pikas, J.L.

    1997-05-01

    External microbiologically influenced corrosion (MIC) is a serious dilemma in the pipeline industry. Even today, it has not been recognized as such because it has been primarily mistaken for galvanic corrosion. Due to the type of coating materials used in the past, the cleaning process or lack of it, and application methods used, all coating systems have the propensity to develop defects and pinholes where disbondment and this type of microbial corrosion could occur. In addition, the pipeline may or may not have had cathodic protection initially and/or consistently applied. Given these factors and the interaction of bacteria from the soil, moisture availability, degree of cathodic protection, and temperature of the pipeline, this paper will discuss the role that microbes play in the disbondment process, thus resulting in corrosion of an underground pipeline. Several case histories, laboratory testing results, and field findings will be presented.

  8. The corrosion behavior of in-situ Zr-based metallic glass matrix composites in different corrosive media

    NASA Astrophysics Data System (ADS)

    Tian, H. F.; Qiao, J. W.; Yang, H. J.; Wang, Y. S.; Liaw, P. K.; Lan, A. D.

    2016-02-01

    The corrosion behavior of Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0 metallic glass matrix composites (MGMCs) in different corrosive media, including 1 M NaCl, 1 M HCl, 0.5 M H2SO4, and 1 M NaOH solutions, was studied. The electrochemical characteristics of the composites were investigated by potentiodynamic-polarization measurements. The results show that the corrosion resistance in NaOH solution is the poorest in terms of the corrosion potential (Ecorr) and corrosion current density (icorr). For comparison, the chemical immersion tests were conducted. The corroded surface morphologies after electrochemical and immersion measurements both show that the amorphous matrix and crystalline dendrites exhibit different corrosion behaviors. The possible interpretation of the observed morphology evolution was proposed. The effect of a very base metallic element of beryllium on the corrosion dynamic process has been emphasized.

  9. Wastewater-Enhanced Microbial Corrosion of Concrete Sewers.

    PubMed

    Jiang, Guangming; Zhou, Mi; Chiu, Tsz Ho; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2016-08-01

    Microbial corrosion of concrete in sewers is known to be caused by hydrogen sulfide, although the role of wastewater in regulating the corrosion processes is poorly understood. Flooding and splashing of wastewater in sewers periodically inoculates the concrete surface in sewer pipes. No study has systematically investigated the impacts of wastewater inoculation on the corrosion of concrete in sewers. This study investigated the development of the microbial community, sulfide uptake activity, and the change of the concrete properties for coupons subjected to periodic wastewater inoculation. The concrete coupons were exposed to different levels of hydrogen sulfide under well-controlled conditions in laboratory-scale corrosion chambers simulating real sewers. It was evident that the periodic inoculation induced higher corrosion losses of the concrete in comparison to noninoculated coupons. Instantaneous measurements such as surface pH did not reflect the cumulative corrosion losses caused by long-term microbial activity. Analysis of the long-term profiles of the sulfide uptake rate using a Gompertz model supported the enhanced corrosion activity and greater corrosion loss. The enhanced corrosion rate was due to the higher sulfide uptake rates induced by wastewater inoculation, although the increasing trend of sulfide uptake rates was slower with wastewater. Increased diversity in the corrosion-layer microbial communities was detected when the corrosion rates were higher. This coincided with the environmental conditions of increased levels of gaseous H2S and the concrete type.

  10. Wastewater-Enhanced Microbial Corrosion of Concrete Sewers.

    PubMed

    Jiang, Guangming; Zhou, Mi; Chiu, Tsz Ho; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2016-08-01

    Microbial corrosion of concrete in sewers is known to be caused by hydrogen sulfide, although the role of wastewater in regulating the corrosion processes is poorly understood. Flooding and splashing of wastewater in sewers periodically inoculates the concrete surface in sewer pipes. No study has systematically investigated the impacts of wastewater inoculation on the corrosion of concrete in sewers. This study investigated the development of the microbial community, sulfide uptake activity, and the change of the concrete properties for coupons subjected to periodic wastewater inoculation. The concrete coupons were exposed to different levels of hydrogen sulfide under well-controlled conditions in laboratory-scale corrosion chambers simulating real sewers. It was evident that the periodic inoculation induced higher corrosion losses of the concrete in comparison to noninoculated coupons. Instantaneous measurements such as surface pH did not reflect the cumulative corrosion losses caused by long-term microbial activity. Analysis of the long-term profiles of the sulfide uptake rate using a Gompertz model supported the enhanced corrosion activity and greater corrosion loss. The enhanced corrosion rate was due to the higher sulfide uptake rates induced by wastewater inoculation, although the increasing trend of sulfide uptake rates was slower with wastewater. Increased diversity in the corrosion-layer microbial communities was detected when the corrosion rates were higher. This coincided with the environmental conditions of increased levels of gaseous H2S and the concrete type. PMID:27390870

  11. Novel corrosion inhibitor technology

    SciTech Connect

    Van de Ven, P.; Fritz, P.; Pellet, R.

    1999-11-01

    A novel, patented corrosion inhibitor technology has been identified for use in heat transfer applications such as automotive and heavy-duty coolant. The new technology is based on a low-toxic, virtually depletion-free carboxylic acid corrosion inhibitor package that performs equally well in mono ethylene glycol and in less toxic propylene glycol coolants. An aqueous inhibitor concentrate is available to provide corrosion protection where freezing protection is not an issue. In the present paper, this inhibitor package is evaluated in the different base fluids: mono ethylene glycol, mono propylene glycol and water. Results are obtained in both standardized and specific corrosion tests as well as in selected field trials. These results indicate that the inhibitor package remains effective and retains the benefits previously identified in automotive engine coolant applications: excellent corrosion protection under localized conditions, general corrosion conditions as well as at high temperature.

  12. Stress corrosion resistant fasteners

    NASA Technical Reports Server (NTRS)

    Roach, T. A.

    1985-01-01

    A family of high performance aerospace fasteners made from corrosion resistant alloys for use in applications where corrosion and stress-corrosion cracking are of major concern are discussed. The materials discussed are mainly A-286, Inconel 718, MP35N and MP159. Most of the fasteners utilize cold worked and aged materials to achieve the desired properties. The fasteners are unique in that they provide a combination of high strength and immunity to stress corrosion cracking not previously attainable. A discussion of fastener stress corrosion failures is presented including a review of the history and a description of the mechanism. Case histories are presented to illustrate the problems which can arise when material selection is made without proper regard for the environmental conditions. Mechanical properties and chemical compositions are included for the fasteners discussed. Several aspects of the application of high performance corrosion resistant fasteners are discussed including galvanic compatibility and torque-tension relationships.

  13. Electrochemical corrosion studies

    NASA Technical Reports Server (NTRS)

    Knockemus, W. W.

    1986-01-01

    The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel.

  14. Effective corrosion monitoring

    SciTech Connect

    Britton, C.F.; Tofield, B.C.

    1988-04-01

    The results of two surveys (conducted in 1981 and 1984) of users of corrosion monitoring equipment are described. The benefits to be obtained from a well-designed corrosion monitoring system, especially if a corrosion control program is used, are outlined together with the difficulties and barriers that can obstruct successful application. Developing methods such as AC impedance, electrochemical noise, and thin layer activation are discussed in view of the comments received from the surveys.

  15. Corrosion Detection Devices

    SciTech Connect

    Howard, B.

    2003-12-01

    Nondestructive Examination Systems' (NDE) specialists at the Department of Energy's Savannah River Site have unique, remotely controllable, corrosion detection capabilities. The corrosion detection devices most frequently used are automated ultrasonic mapping systems, digital radiography imaging devices, infrared imaging, and eddy current mapping systems. These devices have been successfully used in a variety of applications, some of which involve high levels of background radiation. Not only is corrosion located and mapped but other types of anomalies such as cracks have been detected and characterized. Examples of actual corrosion that has been detected will be discussed along with the NDE systems that were used.

  16. Effect of Na2WO4 on Growth Process and Corrosion Resistance of Micro-arc Oxidation Coatings on 2A12 Aluminum Alloys in CH3COONa Electrolyte

    NASA Astrophysics Data System (ADS)

    Lin, Zhaoqing; Yu, Huijun; He, Siyu; Wang, Diangang; Chen, Chuanzhong

    2016-01-01

    Ceramic coatings were deposited on 2A12 aluminum alloys using micro-arc oxidation (MAO) technology in CH3COONa-Na2WO4 electrolyte. The MAO process was studied by recording the current-time curve. The influences of Na2WO4 concentrations on the coatings in CH3COONa electrolyte were investigated. The results show that the Na2WO4 concentrations affect the MAO process and performances of the coatings directly. Na2WO4 in excess is harmful for the formation of Al2O3 in this electrolyte. The corrosion resistance was enhanced with the decrease of Na2WO4 concentration.

  17. Atomistic insights into aqueous corrosion of copper.

    SciTech Connect

    Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S.

    2011-06-21

    Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl{sup -} concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

  18. Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

    SciTech Connect

    Jiao, Zhujie; Was, Gary; Bartels, David

    2015-04-02

    This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

  19. Environmentally Friendly Coating Technology for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Johnsey, Marissa N.; Jolley, Scott T.; Pearman, Benjamin P.; Zhang, Xuejun; Fitzpatrick, Lilliana; Gillis, Mathew; Blanton, Michael; Hanna, Joshua S.; Rawlins, James W.

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry.

  20. Computer aided corrosion surveillance using electrochemical noise techniques

    SciTech Connect

    Reid, S.A.; Quirk, G.P.; Hadfield, M.

    1999-11-01

    Real-time mechanistic analysis of electrochemical noise data is essential for rapid identification of localized corrosion by plant operators. Recent developments towards this goal include: Intelligent Noise Data Reduction techniques to eliminate uninformative data; neural nets which learn how to categorize corrosion mechanisms from data patterns; multivariate analysis which allows the identification of combinations of plant process parameters that cause damage. These techniques can be combined to facilitate pro-active management of the corrosion problem, including consideration of corrosion mechanisms within the plant optimization process.

  1. Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

    PubMed

    Scully, John R

    2015-01-01

    Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

  2. Stress-corrosion cracking in metals

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Criteria and recommended practices for preventing stress-corrosion cracking from impairing the structural integrity and flightworthiness of space vehicles are presented. The important variables affecting stress-corrosion cracking are considered to be the environment, including time and temperature; metal composition, and structure; and sustained tensile stress. For designing spacecraft structures that are free of stress-corrosion cracking for the service life of the vehicle the following rules apply: (1) identification and control of the environments to which the structure will be exposed during construction, storage, transportation, and use; (2) selection of alloy compositions and tempers which are resistant to stress-corrosion cracking in the identified environment; (3) control of fabrication and other processes which may introduce residual tensile stresses or damage the material; (4) limitation of the combined residual and applied tensile stresses to below the threshold stress level for the onset of cracking throughout the service life of the vehicle; and (5) establishment of a thorough inspection program.

  3. Potentiodynamic Corrosion Testing.

    PubMed

    Munir, Selin; Pelletier, Matthew H; Walsh, William R

    2016-01-01

    Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the material. The detection of these electrochemical parameters identifies the corrosion factors of a material. A reliable and well-functioning corrosion system is required to achieve this. Corrosion of the samples was achieved via a potentiodynamic polarization technique employing a three-electrode configuration, consisting of reference, counter, and working electrodes. Prior to commencement a baseline potential is obtained. Following the stabilization of the corrosion potential (Ecorr), the applied potential is ramped at a slow rate in the positive direction relative to the reference electrode. The working electrode was a stainless steel screw. The reference electrode was a standard Ag/AgCl. The counter electrode used was a platinum mesh. Having a reliable and well-functioning in vitro corrosion system to test biomaterials provides an in-expensive technique that allows for the systematic characterization of the material by determining the breakdown potential, to further understand the material's response to corrosion. The goal of the protocol is to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices. PMID:27683978

  4. Aluminum Corrosion and Turbidity

    SciTech Connect

    Longtin, F.B.

    2003-03-10

    Aluminum corrosion and turbidity formation in reactors correlate with fuel sheath temperature. To further substantiate this correlation, discharged fuel elements from R-3, P-2 and K-2 cycles were examined for extent of corrosion and evidence of breaking off of the oxide film. This report discusses this study.

  5. Potentiodynamic Corrosion Testing.

    PubMed

    Munir, Selin; Pelletier, Matthew H; Walsh, William R

    2016-09-04

    Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the material. The detection of these electrochemical parameters identifies the corrosion factors of a material. A reliable and well-functioning corrosion system is required to achieve this. Corrosion of the samples was achieved via a potentiodynamic polarization technique employing a three-electrode configuration, consisting of reference, counter, and working electrodes. Prior to commencement a baseline potential is obtained. Following the stabilization of the corrosion potential (Ecorr), the applied potential is ramped at a slow rate in the positive direction relative to the reference electrode. The working electrode was a stainless steel screw. The reference electrode was a standard Ag/AgCl. The counter electrode used was a platinum mesh. Having a reliable and well-functioning in vitro corrosion system to test biomaterials provides an in-expensive technique that allows for the systematic characterization of the material by determining the breakdown potential, to further understand the material's response to corrosion. The goal of the protocol is to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices.

  6. Fireside Corrosion USC Steering

    SciTech Connect

    G. R. Holcomb; J. Tylczak

    2011-09-07

    Oxy-Fuel Fireside Research goals are: (1) Determine the effect of oxy-fuel combustion on fireside corrosion - (a) Flue gas recycle choice, Staged combustion ramifications, (c) JCOAL Collaboration; and (2) Develop methods to use chromia solubility in ash as an 'ash corrosivity' measurement - (a) Synthetic ashes at first, then boiler and burner rig ashes, (b) Applicable to SH/RH conditions.

  7. Demystifying Controlling Copper Corrosion

    EPA Science Inventory

    The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

  8. The local effects of metal corrosion in total hip arthroplasty.

    PubMed

    Cooper, H John

    2014-01-01

    Corrosion has long been recognized to occur in total hip arthroplasty, but the local effects of this process have only recently become better understood. This article provides an overview of corrosion at modular junctions, and discusses the various etiologic factors for corrosion and the biologic response to metal debris released from this junction. Algorithms are provided for diagnosis and treatment, in accordance with the best available data.

  9. IMPACT OF NUCLEAR MATERIAL DISSOLUTION ON VESSEL CORROSION

    SciTech Connect

    Mickalonis, J.; Dunn, K.; Clifton, B.

    2012-10-01

    Different nuclear materials require different processing conditions. In order to maximize the dissolver vessel lifetime, corrosion testing was conducted for a range of chemistries and temperature used in fuel dissolution. Compositional ranges of elements regularly in the dissolver were evaluated for corrosion of 304L, the material of construction. Corrosion rates of AISI Type 304 stainless steel coupons, both welded and non-welded coupons, were calculated from measured weight losses and post-test concentrations of soluble Fe, Cr and Ni.

  10. Corrosion in methylphosphonic difluoride

    SciTech Connect

    Zabielski, C.V.; Levy, M. )

    1994-12-01

    Electrochemical potentiodynamic polarization studies were conducted for a variety of ferrous and nonferrous metals in methylphosphonic difluoride. Studies were also made of the effects of organic inhibitors on the corrosion rates of 1,020 steel, type 316L, and type 304 stainless steel, and magnesium in methylphosphonic difluoride. Chemical weapons in the US include binary munitions in which two components are kept in separate compartments until activation. These munitions must be stockpiled for long periods of time (up to 30 years) and then must operate reliably when the need arises. The principal cause of failure will be corrosion of the storage container by the highly corrosive methylphosphonic difluoride (DF). The objectives of this study were to: investigate the kinetics and mechanisms of corrosion of Al 6061-T6 and candidate metal alloys in DF; establish effective corrosion inhibitors; and ultimately incorporate or immobilize inhibitors into coatings that provide protection above the liquid line.

  11. Corrosion failures of austenitic stainless steel piping

    SciTech Connect

    Louthan, M.R. Jr.

    1993-10-01

    The safe and efficient operation of many chemical/industrial systems requires the continued integrity of the process piping; this is achieved through a complex series of interactions influenced by design, fabrication, construction, operation, inspection and lay-up requirements. Potential material-enviroment interactions are frequently, if evaluated at all, relegated to secondary considerations. This tendency virtually assures corrosion induced degradation of the process piping systems. Pitting, crevice attack, stress cracking, microbiologically influenced corrosion, intergranular attack and corrosion fatigue have caused leaks, cracks, failures and shutdown of numerous process systems. This paper uses the lessons learned from failure analysis to emphasize the importance of an integrated material program to system success. The necessity of continuing evaluation if also emphasized through examples of failures which were associated with materials-environment interactions caused by slight alterations of processes and/or systems.

  12. Prediction of Corrosion of Advanced Materials and Fabricated Components

    SciTech Connect

    A. Anderko; G. Engelhardt; M.M. Lencka; M.A. Jakab; G. Tormoen; N. Sridhar

    2007-09-29

    The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the fundamental parameters that control the occurrence of localized corrosion as a function of environmental conditions and alloy composition. The fundamental parameters that dictate the occurrence of localized corrosion are the corrosion and repassivation potentials. The program team, OLI Systems and Southwest Research Institute, has developed theoretical models for these parameters. These theoretical models have been applied to predict the occurrence of localized corrosion of base materials and heat-treated components in a variety of environments containing aggressive and non-aggressive species. As a result of this project, a comprehensive model has been established and extensively verified for predicting the occurrence of localized corrosion as a function of environment chemistry and temperature by calculating the corrosion and repassivation potentials.To support and calibrate the model, an experimental database has been developed to elucidate (1) the effects of various inhibiting species as well as aggressive species on localized corrosion of nickel

  13. Review of critical factors affecting crude corrosivity

    SciTech Connect

    Tebbal, S.; Kane, R.D.

    1996-08-01

    Lower quality opportunity crudes are now processed in most refineries and the source of the crudes may vary daily. These feedstocks, if not properly handled, can result in reduction in service life of equipment as well as costly failure and downtime. Analytical tools are needed to predict their high temperature corrosivity toward distillation units. Threshold in total sulfur and total acid number (TAN) have been used for many years as rules of thumb for predicting crude corrosivity, However, it is now realized that they are not accurate in their predictive ability. Crudes with similar composition and comparable with respect to process considerations have been found to be entirely different in their impact on corrosion. Naphthenic acid content, sulfur content, velocity, temperature, and materials of construction are the main factors affecting the corrosion process, Despite progress made in elucidating the role of the different parameters on the crude corrosivity process, the main problem is in calculating their combined effect, especially when the corroding stream is such a complex mixture. The TAN is usually related directly to naphthenic acid content. However, discrepancies between analytical methods and interference of numerous components of the crude itself lead to unreliable reported content of naphthenic acid. The sulfur compounds, with respect to corrosivity, appear to relate more to their decomposition at elevated temperature to form hydrogen sulfide than to their total content in crude. This paper reviews the present situation regarding crude corrosivity in distillation units, with the aim of indicating the extent of available information, and areas where further research is necessary.

  14. Study of iron structure stability in high temperature molten lead-bismuth eutectic with oxygen injection using molecular dynamics simulation

    SciTech Connect

    Arkundato, Artoto; Su'ud, Zaki; Sudarko; Shafii, Mohammad Ali; Celino, Massimo

    2014-09-30

    Corrosion of structural materials in high temperature molten lead-bismuth eutectic is a major problem for design of PbBi cooled reactor. One technique to inhibit corrosion process is to inject oxygen into coolant. In this paper we study and focus on a way of inhibiting the corrosion of iron using molecular dynamics method. For the simulation results we concluded that effective corrosion inhibition of iron may be achieved by injection 0.0532 wt% to 0.1156 wt% oxygen into liquid lead-bismuth. At this oxygen concentration the structure of iron material will be maintained at about 70% in bcc crystal structure during interaction with liquid metal.

  15. Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

    NASA Technical Reports Server (NTRS)

    Pearman, Benjamin Pieter; Li, Wenyan; Buhrow, Jerry; Zhang, Xuejun; Surma, Jan; Fitzpatrick, Lilly; Montgomery, Eliza; Calle, Luz Marina

    2014-01-01

    Research efforts are under way to replace current corrosion inhibitors with more environmentally friendly alternatives. However, problems with corrosion inhibition efficiency, coating compatibility and solubility have hindered the use of many of these materials as simple pigment additives.This paper will present technical details on how the Corrosion Technology Lab at NASAs Kennedy Space Center (KSC) has addressed these issues by encapsulating environmentally friendly inhibitors into organic and inorganic microparticles and microcapsules. The synthetic process for polymer particles was characterized and post-synthesis analysis was performed to determine the interactions between the inhibitors and the encapsulation material. The pH-controlled release of inhibitors from various particle formulations in aqueous base was monitored and compared to both electrochemical and salt immersion accelerated corrosion experiment. Furthermore, synergistic corrosion inhibition effects observed during the corrosion testing of several inhibitor combinations will be presented.

  16. Microbial iron respiration can protect steel from corrosion.

    PubMed

    Dubiel, M; Hsu, C H; Chien, C C; Mansfeld, F; Newman, D K

    2002-03-01

    Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration.

  17. Conducting polymers as corrosion resistant coatings

    SciTech Connect

    Wrobleski, D.A.; Benicewicz, B.C.

    1994-09-01

    Although the majority of top coatings used for corrosion protection are electrically insulating, previous workers have proposed using an electrically active barrier for corrosion control. The most effective corrosion resistant undercoatings in use today are based on chromium compounds. Coatings based on other materials will need to replace these coatings by the turn of the century because of environmental and health concerns. For this reason the authors have begun an investigation of the use of conducting polymers as corrosion resistant coatings as an alternative to metal-based coatings. Conducting polymers have long been considered to be unsuitable for commercial processing, hindering their use for practical applications. Research in the field of electrically conducting polymers has recently produced a number of polymers such as polyaniline and its derivatives which are readily soluble in common organic solvents. The authors coating system, consisting of a conducting polyaniline primer layer, topcoated with epoxy or polyurethane, has been evaluated for corrosion resistance on mild steel substrates. In this paper, the authors report the results of laboratory testing under acidic and saline conditions and the results of testing in the severe launch environment at the Beach Testing Facility at Kennedy Space Center. The launch environment consists of exposure to corrosive HCl exhaust fumes and the salt spray from the Atlantic Ocean.

  18. Environmental factors affecting corrosion of munitions

    SciTech Connect

    Bundy, K.; Bricka, M.; Morales, A.

    1995-12-31

    Spent small arms munitions have accumulated for years at outdoor firing ranges operated by the DoD and other groups. Used bullets are often subjected to moisture sources. There is increasing concern that accumulations of lead-based munitions represent potential sources of water and soil pollution. To understand both the severity of and solutions to this problem, it is necessary to measure how rapidly bullets corrode and to determine the soil variables affecting the process. In this study M16 bullets were buried in samples of soil taken from Louisiana army firing ranges. Four environmental conditions were simulated; rain water, acid rain, sea water, and 50% sea water/50% acid rain. The three electrode technique was used to measure the bullet corrosion. Graphite rods served as counter electrodes. A saturated calomel reference electrode was used along with a specially constructed salt bridge. Electrochemical measurements were conducted using a computer-controlled potentiostat to determine corrosion potential, soil resistance, and corrosion current. The rate of corrosion was found to markedly increase with decreasing soil pH and increasing chloride and moisture contents, with the chloride content being the most influential variable. High soil resistance and noble corrosion potential were found to be associated with low corrosion rates. This is important since both parameters can be readily measured in the field.

  19. Microbiologically influenced corrosion (MIC) of storage tank bottom plates

    NASA Astrophysics Data System (ADS)

    Syafaat, Taufik A.; Ismail, Mokhtar Che

    2015-07-01

    Aboveground atmospheric storage tanks (AST) receive crude oil from offshore for storage and further processing. Integrity issue of AST storing crude oil is not only affected by external corrosion but also internal corrosion from crude oil that supports the growth of the microorganisms originating from the reservoir. The objective of this research is to study the effect of sulfate reduction bacteria (SRB) on the corrosion of AST. The results indicates that SRB has significant effect on the corrosion rate of storage tank bottom plate.

  20. Metallic plate corrosion and uptake of corrosion products by nafion in polymer electrolyte membrane fuel cells.

    PubMed

    Bozzini, Benedetto; Gianoncelli, Alessandra; Kaulich, Burkhard; Kiskinova, Maya; Prasciolu, Mauro; Sgura, Ivonne

    2010-07-19

    Nafion contamination by ferrous-alloy corrosion products, resulting in dramatic drops of the Ohmic potential, is a suspected major failure mode of polymer electrolyte membrane fuel cells that make use of metallic bipolar plates. This study demonstrates the potential of scanning transmission X-ray microscopy combined with X-ray absorption and fluorescence microspectroscopy for exploring corrosion processes of Ni and Fe electrodes in contact with a hydrated Nafion film in a thin-layer cell. The imaged morphology changes of the Ni and Fe electrodes and surrounding Nafion film that result from relevant electrochemical processes are correlated to the spatial distribution, local concentration, and chemical state of Fe and Ni species. The X-ray fluorescence maps and absorption spectra, sampled at different locations, show diffusion of corrosion products within the Nafion film only in the case of the Fe electrodes, whereas the Ni electrodes appear corrosion resistant. PMID:20564283

  1. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  2. Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

    SciTech Connect

    Khan, Inamullah; François, Raoul; Castel, Arnaud

    2014-02-15

    This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks. -- Highlights: •Relationship between crack and corrosion of reinforcement was investigated. •Corrosion results of natural process and then corresponds to in-situ conditions. •Comparison with time predicting model is provided. •Prediction of load-bearing capacity from crack pattern was studied.

  3. Detection of Intergranular Corrosion in Cold Plate Face Sheets

    NASA Technical Reports Server (NTRS)

    Winfree, William P.; Smith, Stephen W.; Piascik, Robert S.; Howell, Patricia A.

    2002-01-01

    Cold plates are critical for cooling electronic systems in the shuttle. As a result of the environmental conditions in which they operate, water can condense between them and a support shelf. In some cases, this water results in intergranular corrosion in the face sheet. If the intergranular corrosion sufficiently penetrates the face sheet, a coolant leak could occur and jeopardize cold plate operation. This paper examines techniques for detecting and characterizing the intergranular corrosion, to enable recertification of cold plates that have been in operation for 15 plus years. Intergranular corrosion was artificially induced in the face sheets of a series of cold plate specimens using an electrochemical process. Some of the cold plate specimens were separated for destructive characterization of the extent of corrosion produced by the electrochemical process and to insure the induced corrosion was intergranular. The rest of the specimens were characterized nondestructively using several techniques. X-ray tomography and ultrasonic techniques provided the best indication of corrosion in these specimens and will be the focus of this paper. An x-ray tomography technique was shown to be the most effective technique for characterizing depth of the intergranular corrosion. From these measurements, corrosion profile maps were developed that were consistent with subsequent destructive evaluations of the specimens. This enabled the assessment of NDE (ondestructive evaluation) standards to evaluate the viability of other NDE techniques. Due to system constraints, a different technique must be used to inspect an entire cold plate. An ultrasonic technique was shown to be very reliable for detection of corrosion in the unbacked regions of the face sheet. The ultrasonic technique was performed in an alcohol bath to avoid additional corrosion during the NDE evaluation. A pulse echo technique that focuses on the RMS value of the signal is shown to be very sensitive to the

  4. Corrosion-resistant uranium

    DOEpatents

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  5. Corrosion-resistant uranium

    DOEpatents

    Hovis, Jr., Victor M.; Pullen, William C.; Kollie, Thomas G.; Bell, Richard T.

    1983-01-01

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  6. Liquid-metal corrosion

    SciTech Connect

    Chopra, O.K.; DeVan, J.H.; Smith, D.L.; Sze, D.K.; Tortorelli, P.F.

    1985-09-01

    A review of corrosion and environmental effects on the mechanical properties of candidate structural alloys for use with liquid metals in fusion reactors is presented. The corrosion/mass transfer behavior of austenitic and ferritic steels and vanadium-base alloys is evaluated to determine the preliminary operating temperature limits for circulating and static liquid-lithium and Pb-17Li systems. The influence of liquid-metal environment on the mechanical properties of structural materials is discussed. Corrosion effects of nitrate and fluoride salts are presented. Requirements for additional data are identified.

  7. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: HD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  8. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  9. Constituent Particle Clustering and Pitting Corrosion

    NASA Astrophysics Data System (ADS)

    Harlow, D. Gary

    2012-08-01

    Corrosion is a primary degradation mechanism that affects the durability and integrity of structures made of aluminum alloys, and it is a concern for commercial transport and military aircraft. In aluminum alloys, corrosion results from local galvanic coupling between constituent particles and the metal matrix. Due to variability in particle sizes, spatial location, and chemical composition, to name a few critical variables, corrosion is a complex stochastic process. Severe pitting is caused by particle clusters that are located near the material surface, which, in turn, serve as nucleation sites for subsequent corrosion fatigue crack growth. These evolution processes are highly dependent on the spatial statistics of particles. The localized corrosion growth rate is primarily dependent on the galvanic process perpetuated by particle-to-particle interactions and electrochemical potentials. Frequently, severe pits are millimeters in length, and these pits have a dominant impact on the structural prognosis. To accommodate large sizes, a model for three-dimensional (3-D) constituent particle microstructure is proposed. To describe the constituent particle microstructure in three dimensions, the model employs a fusion of classic stereological techniques, spatial point pattern analyses, and qualitative observations. The methodology can be carried out using standard optical microscopy and image analysis techniques.

  10. Current and potential distributions in corrosion systems

    SciTech Connect

    Smyrl, W.H.

    1980-01-01

    Current and potential distribution calculations in corrosion are reviewed. The mathematical methods used, and the specific results for galvanic corrosion, cathodic protection, and localized corrosion are described.

  11. Electrochemical study of aluminum corrosion in boiling high purity water

    NASA Technical Reports Server (NTRS)

    Draley, J. E.; Legault, R. A.

    1969-01-01

    Electrochemical study of aluminum corrosion in boiling high-purity water includes an equation relating current and electrochemical potential derived on the basis of a physical model of the corrosion process. The work involved an examination of the cathodic polarization behavior of 1100 aluminum during aqueous oxidation.

  12. BWR steel containment corrosion

    SciTech Connect

    Tan, C.P.; Bagchi, G.

    1996-04-01

    The report describes regulatory actions taken after corrosion was discovered in the drywell at the Oyster Creek Plant and in the torus at the Nine Mile Point 1 Plant. The report describes the causes of corrosion, requirements for monitoring corrosion, and measures to mitigate the corrosive environment for the two plants. The report describes the issuances of generic letters and information notices either to collect information to determine whether the problem is generic or to alert the licensees of similar plants about the existence of such a problem. Implementation of measures to enhance the containment performance under severe accident conditions is discussed. A study by Brookhaven National Laboratory (BNL) of the performance of a degraded containment under severe accident conditions is summarized. The details of the BNL study are in the appendix to the report.

  13. Corrosion Inhibitors for Aluminum.

    ERIC Educational Resources Information Center

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  14. Interaction between corrosion crack width and steel loss in RC beams corroded under load

    SciTech Connect

    Malumbela, Goitseone; Alexander, Mark; Moyo, Pilate

    2010-09-15

    This paper presents results and discussions on an experimental study conducted to relate the rate of widening of corrosion cracks with the pattern of corrosion cracks as well as the level of steel corrosion for RC beams (153 x 254 x 3000 mm) that were corroded whilst subjected to varying levels of sustained loads. Steel corrosion was limited to the tensile reinforcement and to a length of 700 mm at the centre of the beams. The rate of widening of corrosion cracks as well as strains on uncracked faces of RC beams was constantly monitored during the corrosion process, along the corrosion region and along other potential cracking faces of beams using a demec gauge. The distribution of the gravimetric mass loss of steel along the corrosion region was measured at the end of the corrosion process. The results obtained showed that: the rate of widening of each corrosion crack is dependent on the overall pattern of the cracks whilst the rate of corrosion is independent of the pattern of corrosion cracks. A mass loss of steel of 1% was found to induce a corrosion crack width of about 0.04 mm.

  15. Method for inhibiting corrosion

    SciTech Connect

    Wu, Y.; Stapp, P. R.

    1985-12-03

    A composition comprising the reaction adduct or neutralized product resulting from the reaction of a maleic anhydride and an oil containing a polynuclear aromatic compound is provided which, when applied to a metal surface, forms a corrosion-inhibiting film thereon. The composition is particularly useful in the treatment of down-hole metal surfaces in oil and gas wells to inhibit the corrosion of the metal.

  16. 49 CFR 192.925 - What are the requirements for using External Corrosion Direct Assessment (ECDA)?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Corrosion Direct Assessment (ECDA)? 192.925 Section 192.925 Transportation Other Regulations Relating to... External Corrosion Direct Assessment (ECDA)? (a) Definition. ECDA is a four-step process that combines... corrosion to the integrity of a pipeline. (b) General requirements. An operator that uses direct...

  17. 49 CFR 192.925 - What are the requirements for using External Corrosion Direct Assessment (ECDA)?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Corrosion Direct Assessment (ECDA)? 192.925 Section 192.925 Transportation Other Regulations Relating to... External Corrosion Direct Assessment (ECDA)? (a) Definition. ECDA is a four-step process that combines... corrosion to the integrity of a pipeline. (b) General requirements. An operator that uses direct...

  18. 49 CFR 192.925 - What are the requirements for using External Corrosion Direct Assessment (ECDA)?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Corrosion Direct Assessment (ECDA)? 192.925 Section 192.925 Transportation Other Regulations Relating to... External Corrosion Direct Assessment (ECDA)? (a) Definition. ECDA is a four-step process that combines... corrosion to the integrity of a pipeline. (b) General requirements. An operator that uses direct...

  19. 49 CFR 192.925 - What are the requirements for using External Corrosion Direct Assessment (ECDA)?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Corrosion Direct Assessment (ECDA)? 192.925 Section 192.925 Transportation Other Regulations Relating to... External Corrosion Direct Assessment (ECDA)? (a) Definition. ECDA is a four-step process that combines... corrosion to the integrity of a pipeline. (b) General requirements. An operator that uses direct...

  20. Less-Toxic Coatings for Inhibiting Corrosion of Aluminum

    NASA Technical Reports Server (NTRS)

    Minevski, Zoran; Clarke, Eric; Eylem, Cahit; Maxey, Jason; Nelson, Carl

    2003-01-01

    Two recently invented families of conversion- coating processes have been found to be effective in reducing or preventing corrosion of aluminum alloys. These processes offer less-toxic alternatives to prior conversion-coating processes that are highly effective but have fallen out of favor because they generate chromate wastes, which are toxic and carcinogenic. Specimens subjected to these processes were found to perform well in standard salt-fog corrosion tests.

  1. Corrosion Behavior of an Abradable Seal Coating System

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Xu, Cunguan; Lan, Hao; Huang, Chuanbing; Zhou, Yang; Du, Lingzhong; Zhang, Weigang

    2014-08-01

    A novel NiTi/BN composite abradable coating and two traditional Ni/C and Ni/BN coatings were manufactured with NiAl as the bond layer using thermal spray technology and their corrosion behaviors were investigated. In salt spray corrosion testing of the Ni/BN coating, defective sites of the metal matrix were corroded preferentially. Simulated occlusion experiments and electrochemical tests indicated that migration of ions resulted in pH decrease and Cl- enrichment in defects, and a more aggressive electrolyte led to a decrease of the corrosion potential of the metal inside defects but an increase of the corrosion current density, representing an autocatalytic corrosion process. Moreover, galvanic corrosion between the top and bond coatings of the abradable system was studied via the electrochemical technique. The results showed that, for the NiTi/BN, Ni/BN, and Ni/graphite coatings with a NiAl bond coating, current flow was generated between the anode and cathode. The NiTi/BN coating acted as the cathode due to its passivation, while the Ni/BN and Ni/graphite coatings acted as the anode because of their lower corrosion potential compared with the NiAl coating. The anode suffered serious corrosion damage due to galvanic corrosion, while the cathode corroded only slightly.

  2. Corrosion Behaviour of A380 Aluminiun Alloy by Semi-Solid Rheocasting

    SciTech Connect

    Forn, A.; Ruperez, E.; Baile, M. T.; Campillo, M.; Menargues, S.; Espinosa, I.

    2007-04-07

    A comparative study was performed on the corrosion behavior of a component of A380 aluminium alloy obtained by Semi-Solid Rheocasting (SSR). The effect of heat treatments T5 and T6 on corrosion resistance was compared with components without heat treatment by SSR processes. Corrosion studies were performed using an acetic acid salt spray test, impedance measurements and polarization curves using a 3,5%Na Cl test solution. The corrosion progress is described by micrographic analysis.

  3. Hot corrosion and high temperature corrosion behavior of a new gas turbine material -- alloy 603GT

    SciTech Connect

    Agarwal, D.C.; Brill, U.; Klower, J.

    1998-12-31

    Salt deposits encountered in a variety of high temperature processes have caused premature failures in heat exchangers and superheater tubes in pulp and paper recovery boilers, waste incinerators and coal gasifiers. Molten salt corrosion studies in both land based and air craft turbines have been the subject of intense study by many researchers. This phenomenon referred to as ``hot corrosion`` has primarily been attributed to corrosion by alkali sulfates, and there is somewhat general agreement in the literature that this is caused by either basic or acidic dissolution (fluxing) of the protective metal oxide layers by complex salt deposits containing both sulfates and chlorides. This paper describes experimental studies conducted on the hot corrosion behavior of a new Ni-Cr-Al alloy 603GT (UNS N06603) in comparison to some commercially established alloys used in gas turbine components.

  4. Remote measurement of corrosion using ultrasonic techniques

    SciTech Connect

    Garcia, K.M.; Porter, A.M.

    1995-02-01

    Supercritical water oxidation (SCWO) technology has the potential of meeting the US Department of Energy`s treatment requirements for mixed radioactive waste. A major technical constraint of the SCWO process is corrosion. Safe operation of a pilot plant requires monitoring of the corrosion rate of the materials of construction. A method is needed for measurement of the corrosion rate taking place during operation. One approach is to directly measure the change in wall thickness or growth of oxide layer at critical points in the SCWO process. In FY-93, a brief survey of the industry was performed to evaluate nondestructive evaluation (NDE) methods for remote corrosion monitoring in supercritical vessels. As a result of this survey, it was determined that ultrasonic testing (UT) methods would be the most cost-effective and suitable method of achieving this. Therefore, the objective for FY-94 was to prove the feasibility of using UT to monitor corrosion of supercritical vessels remotely during operation without removal of the insulation.

  5. Monitoring corrosion in reinforced concrete structures

    NASA Astrophysics Data System (ADS)

    Kung, Peter; Comanici, Maria I.

    2014-06-01

    Many defects can cause deterioration and cracks in concrete; these are results of poor concrete mix, poor workmanship, inadequate design, shrinkage, chemical and environmental attack, physical or mechanical damage, and corrosion of reinforcing steel (RS). We want to develop a suite of sensors and systems that can detect that corrosion is taking place in RS and inform owners how serious the problem is. By understanding the stages of the corrosion process, we can develop special a sensor that detects each transition. First, moisture ingress can be monitored by a fiber optics humidity sensor, then ingress of Chloride, which acts as a catalyst and accelerates the corrosion process by converting iron into ferrous compounds. We need a fiber optics sensor which can quantify Chloride ingress over time. Converting ferric to ferrous causes large volume expansion and cracks. Such pressure build-up can be detected by a fiber optic pressure sensor. Finally, cracks emit acoustic waves, which can be detected by a high frequency sensor made with phase-shifted gratings. This paper will discuss the progress in our development of these special sensors and also our plan for a field test by the end of 2014. We recommend that we deploy these sensors by visually inspecting the affected area and by identifying locations of corrosion; then, work with the designers to identify spots that would compromise the integrity of the structure; finally, drill a small hole in the concrete and insert these sensors. Interrogation can be done at fixed intervals with a portable unit.

  6. The role of NaCl in flame chemistry, in the deposition process, and in its reactions with protective oxides as related to hot corrosion

    NASA Technical Reports Server (NTRS)

    Kohl, F. J.; Stearns, C. A.

    1979-01-01

    Sodium chloride is believed to be the primary source of turbine engine contamination that contributes to hot corrosion. The behavior of NaCl-containing aerosols ingested with turbine intake air is very complex; some of the NaCl may vaporize during combustion while some may remain as particulates. The NaCl can lead to Na2SO4 formation by several possible routes or it can contribute to corrosion directly. Hydrogen or oxygen atom reaction with NaCl(c) was shown to result in the release of Na(g). Gaseous NaCl in flames can be partially converted to gaseous Na2SO4 by homogeneous reactions. The remaining gaseous NaCl and other Na-containing molecules can act as sodium carriers for condensate deposition of Na2SO4 on cool surfaces. A frozen boundary layer theory was developed to predict the rates of deposition. The condensed phase NaCl can be converted directly to condensed Na2SO4 by reaction with sulfur oxides and O2. Reaction of gaseous NaCl with Cr2O3 results in the vapor phase transport of chromium by the formation of complex Cr-containing gaseous molecules. Similar gaseous complexes are formed with molybdenum. The presence of gaseous NaCl was shown to affect the oxidation kinetics of Ni-Cr alloys. It also causes changes in the surface morphology of Al2O3 scales formed on Al-containing alloys.

  7. Corrosion inhibitive admixtures for concrete (A review of the current state of the art)

    SciTech Connect

    Incorvia, M.J.

    1996-12-01

    Corrosion inhibitive admixtures, chemicals added to the concrete mixture to decrease the corrosion activity of the steel reinforcement, are an easy, cost-effective method for corrosion protection. This paper will review some of the issues related to the corrosion process and to the use of corrosion inhibitive admixtures to extend the service life of steel reinforced structures. The principle cause of corrosion damage to steel reinforced concrete, even high quality concrete, is chloride ion attack. To perform properly an inhibitive admixture must provide protection against chloride induced corrosion. Corrosion inhibitive admixtures provide protection by two mechanisms: (1) a chloride screening mechanism which prolongs the time it takes for chloride to reach the surface of the metal, and (2) an interfacial process where protection is provided by decreasing the corrosion activity at the reinforcing steel surface. The classes of admixtures which prolong the time it takes for chlorides to reach the surface of the reinforcing bars are: hydrophobic materials, pozzolanic materials (e.g. silica fume, fly ash, etc.), and superplasticizers. Interfacial corrosion inhibitive admixtures provide protection by decreasing the corrosion activity by a thermodynamic or a kinetic process or both. The science and technology of corrosion inhibitive admixtures is a developing area, and as such, universally accepted testing procedures have not been established. For the more recently developed admixtures, long duration field exposure test data are not yet available.

  8. Research needs for corrosion control and prevention in energy conservation systems

    SciTech Connect

    Brooman, E.W.; Hurwitch, J.W.

    1985-06-01

    A group of 28 electrochemists, materials scientists and corrosion engineers was brought together to determine if the government could have a role as a focal point for corrosion R and D, discuss opportunities in fundamental research and solving corrosion problems, and develop a research agenda. Participants from government, industry and academia assembled into four technical discussion groups: localized corrosion, general corrosion, high temperature corrosion, and corrosion control and prevention. Research needs were identified, discussed, then assigned a figure of merit. Some 44 corrosion control and prevention topics were identified as having a high priority for consideration for funding. Another 35 topics were identified as having a medium priority for funding. When classified according to corrosion phenomenon, the areas which should receive the most attention are molten salt attack, crevice corrosion, stress-corrosion cracking, erosion-corrosion, pitting attack, intergranular attack and corrosion fatigue. When classified according to the sector or system involved, those which should receive the most attention are chemical processes, transportation, buildings and structures, electric power generation, and batteries and fuel cells.

  9. A system for characterizing Mg corrosion in aqueous solutions using electrochemical sensors and impedance spectroscopy.

    PubMed

    Doepke, Amos; Kuhlmann, Julia; Guo, Xuefei; Voorhees, Robert T; Heineman, William R

    2013-11-01

    Understanding Mg corrosion is important to the development of biomedical implants made from Mg alloys. Mg corrodes readily in aqueous environments, producing H2, OH- and Mg2+. The rate of formation of these corrosion products is especially important in biomedical applications where they can affect cells and tissue near the implant. We have developed a corrosion characterization system (CCS) that allows realtime monitoring of the solution soluble corrosion products OH-, Mg2+, and H2 during immersion tests commonly used to study the corrosion of Mg materials. Instrumentation was developed to allow the system to also record electrochemical impedance spectra simultaneously in the same solution to monitor changes in the Mg samples. We demonstrated application of the CCS by observing the corrosion of Mg (99.9%) in three different corrosion solutions: NaCl, HEPES buffer, and HEPES buffer with NaCl at 37°C for 48 h. The solution concentrations of the corrosion products measured by sensors correlated with the results using standard weight loss measurements to obtain corrosion rates. This novel approach gives a better understanding of the dynamics of the corrosion process in realtime during immersion tests, rather than just providing a corrosion rate at the end of the test, and goes well beyond the immersion tests that are commonly used to study the corrosion of Mg materials. The system has the potential to be useful in systematically testing and comparing the corrosion behavior of different Mg alloys, as well as protective coatings.

  10. Comparison of TGSCC and crevice corrosion in a brass/nitrite system

    SciTech Connect

    Edgemon, G.L.; Bell, G.E.C.; Mickalonis, J.I.

    1999-11-01

    The use of electrochemical noise based corrosion monitoring equipment to detect localized corrosion in laboratory and process systems has increased markedly over the last five years. One of the most interesting systems to study is the stress corrosion cracking of UNS C22000 brass exposed to 1-M sodium nitrite (NaNO{sub 2}) at ambient temperature. This test has been proposed as a possible standard for evaluating electrochemical noise equipment. Stressed brass specimens exposed to this environment consistently display the same movement from general corrosion to passivation to transgranular stress corrosion cracking. In an effort to better understand the complex patterns of data this system is capable of producing, crevice corrosion tests using similar specimens and environments were performed. Data from the stress corrosion cracking tests are presented and compared with data from the crevice corrosion tests.

  11. Coating Prospects in Corrosion Prevention of Aluminized Steel and Its Coupling with Magnesium

    NASA Astrophysics Data System (ADS)

    Sun, Fuyan

    In this study, a plasma electrolytic oxidation (PEO) process was used to form oxide coating on aluminized steel, heated aluminized steel and magnesium. A potentiodynamic polarization corrosion test was employed to investigate the general corrosion properties. Galvanic corrosion of steel samples and magnesium samples was studied by zero resistance ammeter (ZRA) tests and boiling tests. Scanning electron microscopy (SEM) and EDS were used to investigate the coating microstructure and the coating/substrate interface. In general, the PEO coatings on all three substrate can help prevent general corrosion. 6-min coated magnesium with unipolar current mode performs best in most galvanic couplings for preventing both general corrosion and galvanic corrosion. Factors which could influence galvanic corrosion behaviors of tested samples were discussed based on area ratios of anode/cathode and cell potential driving force during the ZRA corrosion tests and boiling tests.

  12. Corrosion testing using isotopes

    DOEpatents

    Hohorst, Frederick A.

    1995-12-05

    A method for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness.

  13. Corrosion testing using isotopes

    DOEpatents

    Hohorst, F.A.

    1995-12-05

    A method is described for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested is described composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested is described composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness. 3 figs.

  14. Detecting Corrosion Under Paint and Insulation

    NASA Technical Reports Server (NTRS)

    Bastin, Gary L.

    2011-01-01

    Corrosion is a major concern at the Kennedy Space Center in Florida due to the proximity of the center to the Atlantic Ocean and to salt water lagoons. High humidity, salt fogs, and ocean breezes, provide an ideal environment in which painted steel structures become corroded. Maintenance of painted steel structures is a never-ending process.

  15. Microbially-influenced corrosion capability of Yucca Mountain bacterial isolates

    SciTech Connect

    Pitonzo, B.; Castro, P.; Amy, P.

    1996-12-01

    Microorganisms implicated in microbially-influenced corrosion have been isolated from the deep subsurface at Yucca Mt. Iron-oxidizing (FeOx), sulfate-reducing (SRB), and exopolymer (EPS)-producing bacteria were found. Microbial corrosion rate was monitored electrochemically. The test system was composed of a 1020 carbon steel coupon immersed in soft R2A agar prepared with simulated groundwater (J-13). A KCl bridge was used to connect the test and reference cell (calomel electrode). A platinum counter-electrode was used to apply a potential to the coupon and the corrosion process was measured by a potentiostat (Gamry). Corrosion cells (3x) were inoculated with purified cultures of EPS-producing bacteria and enrichment cultures of FeOx and SRB bacteria. Test cells were inoculated with microorganisms separately, as well as in various combinations. An uninoculated control cell was prepared to assess abiotic corrosion. Average corrosion rates were measured in milli-inches per year (mpy) against time. The control, and cells containing EPS-producing, FeOx or SRB bacteria alone or in combination demonstrated a rapid decrease in corrosion rate by 3 days. The corrosion rates stabilized, and at 35 days peaked at 2.25 mpy (FeOx), 3.30 mpy (SRB), and 2.80 mpy (EPS). AU of these values were significantly higher than the corrosion rate observed in the control cell, 1.30 mpy at 35 days. The various combinations demonstrated higher corrosion rates than any bacterial group alone. Coupons were cleaned, revealing surface pits. 200 pits/sq. in. were counted on a coupon previously exposed to a mixture of EPS-producing and FeOx microorganisms. Pit diameter ranged from 0.25 to 2.75 mm. The results indicate that Yucca Mountain microorganisms, alone and in combination, are capable of causing corrosion of 1020 carbon steel.

  16. Practical aspects of corrosion fundamentals

    SciTech Connect

    Isaacs, H.S.

    1994-08-01

    Aspects important in corrosion have been introduced. They are: (a) ``Pourbaix Diagrams`` which consider thermodynamic stability of metals as a function of electrical potential and water pH; (b) the anodic interfacial reaction rates which depend on potential and accumulation of reaction products; (c) the prediction of polarization curves based on the kinetics and thermodynamics; and (d) localized corrosion models, as this form of corrosion is a major cause of corrosion failures.

  17. Corrosion-resistant metal surfaces

    DOEpatents

    Sugama, Toshifumi

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  18. Corrosion Monitoring System

    SciTech Connect

    Dr. Russ Braunling

    2004-10-31

    The Corrosion Monitoring System (CMS) program developed and demonstrated a continuously on-line system that provides real-time corrosion information. The program focused on detecting pitting corrosion in its early stages. A new invention called the Intelligent Ultrasonic Probe (IUP) was patented on the program. The IUP uses ultrasonic guided waves to detect small defects and a Synthetic Aperture Focusing Technique (SAFT) algorithm to provide an image of the pits. Testing of the CMS demonstrated the capability to detect pits with dimensionality in the sub-millimeter range. The CMS was tested in both the laboratory and in a pulp and paper industrial plant. The system is capable of monitoring the plant from a remote location using the internet.

  19. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K. NY); Cunningham, Kevin M.

    2011-06-07

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  20. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  1. Corrosion analysis of accumulative roll bonded aluminum 6016

    NASA Astrophysics Data System (ADS)

    Searcy, Jacquelyn Alisha

    Accumulative Roll Bonding is a Severe Plastic Deformation Process that is used to strengthen a material and promote grain refinement. Accumulative Roll Bonded Aluminum 6016 samples were investigated to determine their corrosion properties. The tests performed consisted of standard techniques including Cyclic Polarization Potentials, Exfoliation Corrosion (EXCO), Electrochemical Impedance Spectroscopy (EIS), Light Microscopy, and Electron Microprobe Analysis. From these tests, it was determined that for Al 6016, the Ultra Fine Grained samples obtained by Accumulative Roll Bonding are in general more susceptible to corrosion than the coarse grained sample. The higher corrosion rate was caused by the additional cold work, which increased the number of grain boundaries and rolled-in debris. The advantage however was that the corrosion was parallel to the surface and rather than deep into the sample as with the as-received 6016.

  2. Effects of microbial redox cycling of iron on cast iron pipe corrosion in drinking water distribution systems.

    PubMed

    Wang, Haibo; Hu, Chun; Zhang, Lili; Li, Xiaoxiao; Zhang, Yu; Yang, Min

    2014-11-15

    Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on cast iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of iron, to enhance the precipitation of iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including iron-respiring bacteria and Rhizobium which captured iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of iron with associated microbial capture of iron caused more compact corrosion scales formation and lower iron release.

  3. Aqueous corrosion behavior of uranium-molybdenum alloys

    NASA Astrophysics Data System (ADS)

    Gardner, Levi D.

    Nuclear fuel characterization requires understanding of the various conditions to which materials are exposed in-reactor. One of these important conditions is corrosion, particularly that of fuel constituents. Therefore, corrosion behavior is of special interest and an essential part of nuclear materials characterization efforts. In support of the Office of Material Management and Minimization's Reactor Conversion Program, monolithic uranium-10 wt% molybdenum alloy (U-Mo) is being investigated as a low enriched uranium alternative to highly enriched uranium dispersion fuel currently used in domestic high performance research reactors. The aqueous corrosion behavior of U-Mo is being examined at Pacific Northwest National Laboratory (PNNL) as part of U-Mo fuel fabrication capability activity. No prior study adequately represents this behavior given the current state of alloy composition and thermomechanical processing methods, and research reactor water chemistry. Two main measurement techniques were employed to evaluate U-Mo corrosion behavior. Low-temperature corrosion rate values were determined by means of U-Mo immersion testing and subsequent mass-loss measurements. The electrochemical behavior of each processing condition was also qualitatively examined using the techniques of corrosion potential and anodic potentiodynamic polarization. Scanning electron microscopy (SEM) and optical metallography (OM) imagery and hardness measurements provided supplemental corrosion analysis in an effort to relate material corrosion behavior to processing. The processing effects investigated as part of this were those of homogenization heat treatment (employed to mitigate the effects of coring in castings) and sub-eutectoid heat treatment, meant to represent additional steps in fabrication (such as hot isostatic pressing) performed at similar temperatures. Immersion mass loss measurements and electrochemical results both showed very little appreciable difference between

  4. Application of simulation techniques for internal corrosion prediction

    SciTech Connect

    Palacios T, C.A.; Hernandez, Y.

    1997-08-01

    Characterization of corrosion in the oil and gas industry is becoming of increasing importance for safety reasons as well as for the preservation of production facilities; to prevent down time and damage to the environment. This article presents the methodology used by this company to characterize the corrosion behavior of the whole production facility, taking into consideration the hydrodynamic and thermodynamic conditions of the produced fluids (flow velocities, flow pattern, liquid holdup, pressure, temperature, etc.) as they flow from the reservoir through the surface installations (flowlines, gas/oil gathering and transmission lines, gas processing plants, artificial lift systems, etc.). The methodology uses Petroleum Engineering and Two-Phase modeling techniques to: (1) optimize the entire production system to obtain the most efficient objective flow rate taking into consideration the corrosive/erosive nature of the produced fluid and (2) characterize the corrosive nature of the produced fluid as it flows through the above mentioned installations. The modeling techniques were performed using commercially available simulators and CO{sub 2} corrosion rates were determined using well known published correlations. For H{sub 2}S corrosion, NACE MR0175 criteria is applied. The application of this methodology has allowed corrosion control strategies, protection and monitoring criteria, inhibitor optimization and increased the effectiveness of already existing corrosion control systems.

  5. Relationship between corrosion and the biological sulfur cycle: A review

    SciTech Connect

    Little, B.J.; Ray, R.I.; Pope, R.K.

    2000-04-01

    Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numbers and types of sulfur-related organisms and the probability or rate of corrosion, Determination of specific mechanisms for corrosion caused by microbiologically mediated oxidation and reduction of sulfur and sulfur compounds is complicated by the variety of potential metabolic-energy sources and by-products; the coexistence of reduced and oxidized sulfur species; competing reactions with inorganic and organic compounds; and the versatility and adaptability of microorganisms in biofilms. The microbial ecology of sulfur-rich environments is poorly understood because of the association of aerobes and anaerobes and the mutualism or succession of heterotrophs to autotrophs. The physical scale over which the sulfur cycle influences corrosion varies with the environment. The complete sulfur cycle of oxidation and reduction reactions can take place in macroenvironments, including sewers and polluted harbors, or within the microenvironment of biofilms. In this review, reactions of sulfur and sulfur compounds resulting in corrosion were discussed in the context of environmental processes important to corrosion.

  6. Treatment Prevents Corrosion in Steel and Concrete Structures

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In the mid-1990s, to protect rebar from corrosion, NASA developed an electromigration technique that sends corrosion-inhibiting ions into rebar to prevent rust, corrosion, and separation from the surrounding concrete. Kennedy Space Center worked with Surtreat Holding LLC, of Pittsburgh, Pennsylvania, a company that had developed a chemical option to fight structural corrosion, combining Surtreat's TPS-II anti-corrosive solution and electromigration. Kennedy's materials scientists reviewed the applicability of the chemical treatment to the electromigration process and determined that it was an effective and environmentally friendly match. Ten years later, NASA is still using this approach to fight concrete corrosion, and it has also developed a new technology that will further advance these efforts-a liquid galvanic coating applied to the outer surface of reinforced concrete to protect the embedded rebar from corrosion. Surtreat licensed this new coating technology and put it to use at the U.S. Army Naha Port, in Okinawa, Japan. The new coating prevents corrosion of steel in concrete in several applications, including highway and bridge infrastructures, piers and docks, concrete balconies and ceilings, parking garages, cooling towers, and pipelines. A natural compliment to the new coating, Surtreat's Total Performance System provides diagnostic testing and site analysis to identify the scope of problems for each project, manufactures and prescribes site-specific solutions, controls material application, and verifies performance through follow-up testing and analysis.

  7. Steel reinforcement corrosion detection with coaxial cable sensors

    NASA Astrophysics Data System (ADS)

    Muchaidze, Iana; Pommerenke, David; Chen, Genda

    2011-04-01

    Corrosion processes in the steel reinforced structures can result in structural deficiency and with time create a threat to human lives. Millions of dollars are lost each year because of corrosion. According to the U. S. Federal Highway Administration (FHWA) the average annual cost of corrosion in the infrastructure sector by the end of 2002 was estimated to be $22.6 billion. Timely remediation/retrofit and effective maintenance can extend the structure's live span for much less expense. Thus the considerable effort should be done to deploy corrosion monitoring techniques to have realistic information on the location and the severity of damage. Nowadays commercially available techniques for corrosion monitoring require costly equipment and certain interpretational skills. In addition, none of them is designed for the real time quality assessment. In this study the crack sensor developed at Missouri University of Science and Technology is proposed as a distributed sensor for real time corrosion monitoring. Implementation of this technology may ease the pressure on the bridge owners restrained with the federal budget by allowing the timely remediation with the minimal financial and labor expenses. The sensor is instrumented in such a way that the location of any discontinuity developed along its length can be easily detected. When the sensor is placed in immediate vicinity to the steel reinforcement it is subjected to the same chemical process as the steel reinforcement. And corrosion pitting is expected to develop on the sensor exactly at the same location as in the rebar. Thus it is expected to be an effective tool for active corrosion zones detection within reinforced concrete (RC) members. A series of laboratory tests were conducted to validate the effectiveness of the proposed methodology. Nine sensors were manufactured and placed in the artificially created corrosive environment and observed over the time. To induce accelerated corrosion 3% and 5% Na

  8. Corrosion of steel in simulated nuclear waste solutions

    SciTech Connect

    Mickalonis, J.I.

    1993-12-01

    Processing of inhibited nuclear waste to forms for long-term storage will cause waste tank environments to have dynamic conditions. During processing compositional changes in the waste may produce a corrosive environment for the plain carbon steel tanks. Large concentrations of nitrates which corrode steel are contained in the waste. Nitrite and hydroxides are added to inhibit any corrosion. Concentration changes of nitrate and nitrite were investigated to identify corrosion regimes that may occur during processing. Corrosion testing was performed with cyclic potentiodynamic polarization and linear polarization resistance. Test samples were plain carbon steel which was similar to the material of construction of the waste tanks. The corrosion morphology of test samples was investigated by visual evaluation and scanning electron microscopy. Qualitative chemical analysis was also performed using energy dispersive spectroscopy. The corrosion mechanism changed as a function of the nitrate concentration. As the nitrate concentration was increased the steel transitioned from a passive state to general attack, and finally pitting and crevice corrosion. The nitrate anion appeared to destabilize the surface oxide. Nitrite countered the oxide breakdown, although the exact mechanism was not determined.

  9. Characterization of volatile corrosion inhibitors using the quartz crystal microbalance and supporting techniques

    SciTech Connect

    Jaeger, P.F.

    1997-08-01

    Corrosion inhibitors such as Volatile Corrosion Inhibitors (VCI`s) and Contact Corrosion Inhibitors have become loosely ambiguous and differentiating between the two can become a gray area. For example, and the most common mistake is, classifying a material as a VCI when it is a contact inhibitor. Analytical techniques to qualify a material as a VCI have been investigated in order to clarify this ambiguity and to qualify the techniques and equipment for use in the determination of a VCI. The Quartz Crystal Microbalance (QCM) and an atmospheric corrosion monitor were used to characterize adsorption effects and corrosion monitoring of two commercially known inhibitors, sodium nitrite and dicyclohexylammonium nitrite on evaporated iron during atmospheric conditions. Two devices will be used for in situ measurements of adsorption, the QCM and an atmospheric corrosion monitor. During the adsorption process the QCM measures a frequency change that can be associated to a mass change due to adsorption of the inhibitor it is also capable of in situ monitoring corrosion rates of the substrate in a corrosive atmosphere. From experience and in theory the corrosion rate is expected to decrease due to the adsorption of the VCI. Which has been observed from in situ measurements using the QCM. The atmospheric corrosion monitor measures the resistance of oxides of a substrate due to corrosion in reference to a non-corrosive element. It is tested here to measure its sensitivity in comparison to the QCM and to characterize its response during the adsorption of a VCI.

  10. Vanadium corrosion studies. Final report, 1 February 1989-30 June 1993

    SciTech Connect

    Bornstein, N.; Roth, H.; Pike, R.

    1993-06-30

    Vanadium present in certain crude and residual fuel oils, is converted within the burner of the gas turbine engine to the refractory dioxide, which in flight is fully oxidized to the pentoxide. Yttrium oxide, stable in the presence of the oxides of sulfur is identified and verified as a corrosion inhibitor. A chelation process to produce a hydrolytic stable fuel soluble yttrium additive is described.... Vanadium oxide corrosion, Hot corrosion, Sulfidation corrosion, Hot corrosion attenuation, Fuel additives, Water stable fuel soluble yttrium compounds, Chelation.

  11. Copper corrosion in coastal Oregon

    SciTech Connect

    Ballard, Sophie J.; Cramer, Stephen D.; Covino, Bernard S. Jr.; Holcomb, Gordon R.

    1998-01-01

    The US Department of Energy is studying the atmospheric corrosion performance of copper and other metals along the Oregon coast. Only the copper results will be presented in this paper. Atmospheric corrosion measurements of copper samples were made at seven bridges, eight coastal communities, and three inland reference sites to quantify and understand the effect of high chloride environments on the corrosion performance of copper. The materials were atmospherically exposed for 1, 2, and 3 years to examine the effects of sheltering, orientation, distance from the ocean, and coastal microclimates on the rate of corrosion and the composition of the corrosion film.

  12. General Corrosion and Localized Corrosion of the Drip Shield

    SciTech Connect

    F. Hua; K. Mon

    2003-06-24

    The recommended waste package (WP) design is described in BSC (2001a). The design includes a double-wall WP underneath a protective drip shield (DS) (BSC 2003a). The purpose of the process-level models developed in this report is to model dry oxidation (DOX), general corrosion (GC) and localized corrosion (LC) of the DS plate material, which is made of Ti Grade 7. The DS design also includes structural supports fabricated from Ti Grade 24. Degradation of Ti Grade 24 is not considered in this report. The DS provides protection for the waste package outer barrier (WPOB) both as a barrier to seepage water contact and a physical barrier to potential rockfall. This Model Report (MR) serves as a feed to the Integrated Waste Package Degradation Model (IWPD) analyses, and was developed in accordance with the Technical Work Plan (TWP) (BSC 2002a). The models contained in this report serve as a basis to determine whether or not the performance requirements for the DS can be met.

  13. Corrosion protection by anaerobiosis.

    PubMed

    Volkland, H P; Harms, H; Wanner; Zehnder, A J

    2001-01-01

    Biofilm-forming bacteria can protect mild (unalloyed) steel from corrosion. Mild steel coupons incubated with Rhodoccocus sp. strain C125 and Pseudomonas putida mt2 in an aerobic phosphate-buffered medium containing benzoate as carbon and energy source, underwent a surface reaction leading to the formation of a corrosion-inhibiting vivianite layer [Fe3(PO4)2]. Electrochemical potential (E) measurements allowed us to follow the buildup of the vivianite cover. The presence of sufficient metabolically active bacteria at the steel surface resulted in an E decrease to -510 mV, the potential of free iron, and a continuous release of ferrous iron. Part of the dissolved iron precipitated as vivianite in a compact layer of two to three microns in thickness. This layer prevented corrosion of mild steel for over two weeks, even in a highly corrosive medium. A concentration of 20 mM phosphate in the medium was found to be a prerequisite for the formation of the vivianite layer.

  14. TRU drum corrosion task team report

    SciTech Connect

    Kooda, K.E.; Lavery, C.A.; Zeek, D.P.

    1996-05-01

    During routine inspections in March 1996, transuranic (TRU) waste drums stored at the Radioactive Waste Management Complex (RWMC) were found with pinholes and leaking fluid. These drums were overpacked, and further inspection discovered over 200 drums with similar corrosion. A task team was assigned to investigate the problem with four specific objectives: to identify any other drums in RWMC TRU storage with pinhole corrosion; to evaluate the adequacy of the RWMC inspection process; to determine the precise mechanism(s) generating the pinhole drum corrosion; and to assess the implications of this event for WIPP certifiability of waste drums. The task team investigations analyzed the source of the pinholes to be Hcl-induced localized pitting corrosion. Hcl formation is directly related to the polychlorinated hydrocarbon volatile organic compounds (VOCs) in the waste. Most of the drums showing pinhole corrosion are from Content Code-003 (CC-003) because they contain the highest amounts of polychlorinated VOCs as determined by headspace gas analysis. CC-001 drums represent the only other content code with a significant number of pinhole corrosion drums because their headspace gas VOC content, although significantly less than CC-003, is far greater than that of the other content codes. The exact mechanisms of Hcl formation could not be determined, but radiolytic and reductive dechlorination and direct reduction of halocarbons were analyzed as the likely operable reactions. The team considered the entire range of feasible options, ranked and prioritized the alternatives, and recommended the optimal solution that maximizes protection of worker and public safety while minimizing impacts on RWMC and TRU program operations.

  15. Nanocontainer-based corrosion sensing coating.

    PubMed

    Maia, F; Tedim, J; Bastos, A C; Ferreira, M G S; Zheludkevich, M L

    2013-10-18

    The present paper reports on the development of new sensing active coating on the basis of nanocontainers containing pH-indicating agent. The coating is able to detect active corrosion processes on different metallic substrates. The corrosion detection functionality based on the local colour change in active cathodic zones results from the interaction of hydroxide ions with phenolphthalein encapsulated in mesoporous nanocontainers which function as sensing nanoreactors. The mesoporous silica nanocontainers are synthesized and loaded with pH indicator phenolphthalein in a one-stage process. The resulting system is mesoporous, which together with bulkiness of the indicator molecules limits their leaching. At the same time, penetration of water molecules and ions inside the container is still possible, allowing encapsulated phenolphthalein to be sensitive to the pH in the surrounding environment and outperforming systems when an indicator is directly dispersed in the coating layer.The performed tests demonstrate the pH sensitivity of the developed nanocontainers being dispersed in aqueous solutions. The corrosion sensing functionality of the protective coatings with nanocontainers are proven for aluminium- and magnesium-based metallic substrates. As a result, the developed nanocontainers show high potential to be used in a new generation of active protective coatings with corrosion-sensing coatings.

  16. Localized Corrosion of Alloy 22 -Fabrication Effects-

    SciTech Connect

    Rebak, R B

    2005-11-05

    This report deals with the impact of fabrication processes on the localized corrosion behavior of Alloy 22 (N06022). The four fabrication processes that were analyzed are: (1) Surface stress mitigation of final closure weld, (2) Manufacturing of the mockup container, (3) Black annealing of the container and (4) Use of different heats of Alloy 22 for container fabrication. Immersion and Electrochemical tests performed in the laboratory are generally aggressive and do not represent actual repository environments in Yucca Mountain. For example, to determine the intergranular attack in the heat affected zone of a weldment, tests are conducted in boiling acidic and oxidizing solutions according to ASTM standards. These solutions are used to compare the behavior of differently treated metallic coupons. Similarly for electrochemical tests many times pure sodium chloride or calcium chloride solutions are used. Pure chloride solutions are not representative of the repository environment. (1) Surface Stress Mitigation: When metallic plates are welded, for example using the Gas Tungsten Arc Welding (GTAW) method, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to comparatively test the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results from both immersion and electrochemical corrosion tests show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied. (2) Behavior of Specimens from a Mockup container: Alloy 22 has been extensively tested for

  17. Corrosion performance of alumina scales in coal gasification environments

    SciTech Connect

    Natesan, K.

    1997-02-01

    Corrosion of metallic structural materials in complex gas environments of coal gasification is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H{sub 2}S and Cl as HCl. This paper examines the corrosion performance of alumina scales that are thermally grown on Fe-base alloys during exposure to O/S mixed-gas environments. The results are compared with the performance of chromia-forming alloys in similar environments. The paper also discusses the available information on corrosion performance of alloys whose surfaces were enriched with Al by the pack-diffusion process, by the electrospark deposition process, or by weld overlay techniques.

  18. Monitoring and measuring corrosion under coating by optical interferometry

    SciTech Connect

    Habib, K.; Al-Sabti, F.

    1996-10-01

    In a previous study, a mathematical model relating surface and bulk behaviors of metals in aqueous solution has been developed. The model was established based on principles of holographic interferometry for measuring microsurface dissolution, i.e. mass loss, and on those of electrochemistry for measuring the bulk electronic current, i.e. corrosion current. In the present work, an optical corrosion-meter was built based on the above model. The corrosion meter consists of an electrochemical cell in which coated metallic samples are tested in aqueous solutions. Furthermore, the corrosion meter has a holographic camera with a thermoplastic film for in situ processing holograms in order to obtain real time-holographic interferograms of the sample in the electrochemical cell. During experiments, the samples remain in aqueous solution without any physical contact. In the meantime, corrosion data can be obtained from the interpretation of the interferograms of the sample as a function of the elapsed time of the experiments. Also, the open circuit potential of the sample is measured with respect to the interferometric data. Consequently, corrosion current density of epoxy coated aluminum, stainless steel, and low carbon steel in 1M KCl, 1M NaCl, and 1M NaOH solutions were obtained by using the optical corrosion-meter. A comparison between the corrosion data of the different alloys showed that the corrosion current density of the coated stainless steel in 1 M NaCi is nearly three fold higher than that of the coated carbon steel in 1 M NaOH. In contrast, the coated aluminum sample shows no sign of corrosion in 1M KCl.

  19. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    PubMed Central

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  20. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique.

    PubMed

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-09-08

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)₂ solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete.

  1. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique.

    PubMed

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)₂ solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  2. Studies of corrosion and corrosion control in a CO{sub 2}-2-amino-2-methyl-1-propanol (AMP) environment

    SciTech Connect

    Veawab, A.; Tontiwachwuthikul, P.; Bhole, S.D.

    1997-01-01

    The carbon dioxide (CO{sub 2}) absorption process is essential for many industrial processing operations, i.e., natural gas purification. Corrosion and corrosion inhibition in a sterically hindered amine, 2-amino-2-methyl-1-propanol (AMP), were investigated by static weight loss tests. The corrosion data were compared with those of monoethanolamine (MEA), a conventional alkanolamine, which was simultaneously tested under the same conditions. The results indicated that the AMP system was generally less corrosive to carbon steel than the MEA system, but corrosion control is still necessary. Sodium metavanadate (NaVO{sub 3}) and sodium sulfite (Na{sub 2}SO{sub 3}) were proven to be effective corrosion inhibitors, with more than 90% protection efficiency.

  3. Compilation of corrosion data on CAN-DECON. Volume 2. Influence of CAN-DECON on stress corrosion cracking - summary of testing, 1975-1983. Final report

    SciTech Connect

    Michalko, J.P.; Smee, J.L.

    1985-10-01

    An evaluation of the corrosive effect of the CAN-DECON chemical decontamination process on a wide range of BWR materials revealed no significant general, galvanic, crevice, or pitting attack. Before utilities can use the process for routine BWR decontaminations, however, they must determine its effects on stress corrosion cracking.

  4. Amine corrosion inhibitor successful in tests at Mobil's Paulsboro refinery

    SciTech Connect

    Not Available

    1986-11-03

    Mobil Oil Corp. has successfully completed a test of an amine unit corrosion inhibition system at its 100,000-b/d refinery in Paulsboro, NJ. The system, the Amine Guard ST system is used to inhibit corrosion of diethanolamine (DEA) sweetening units that treat process streams from the fluid catalytic cracker (FCC), a hydrodesulfurization unit (HDU), and lube oil dewaxing (LDW) units at the refinery. Use of the corrosion-inhibition system has allowed an increase in the DEA concentration to 55 wt %, a reduction of the DEA circulation rate by 40%, and a reduction in regeneration steam of 35%.

  5. Hot corrosion of S-57, 1 cobalt-base alloy

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.

    1977-01-01

    A cobalt base alloy, S-57, was hot corrosion tested in Mach 0.3 burner rig combustion gases at maximum alloy temperatures of 900 and 1000 C. Various salt concentrations were injected into the burner: 0.5, 2, 5, and 10 ppm synthetic sea salt and 4 ppm sodium sulfate (Na2SO4). S-57 underwent accelerated corrosion only under the most severe test conditions, for example, 4 ppm Na2SO4 at 900 C. The process of the accelerated corrosion was primarily sulfidation.

  6. Development of an Accelerated Test Method for the Determination of Susceptibility to Atmospheric Corrosion

    NASA Technical Reports Server (NTRS)

    Ambrose, John R.

    1991-01-01

    The theoretical rationale is presented for use of a repetitive cyclic current reversal voltammetric technique for characterization of localized corrosion processes, including atmospheric corrosion. Applicability of this proposed experimental protocol is applied to characterization of susceptibility to crevice and pitting corrosion, atmospheric corrosion and stress corrosion cracking. Criteria upon which relative susceptibility is based were determined and tested using two iron based alloys commonly in use at NASA-Kennedy; A36 (a low carbon steel) and 4130 (a low alloy steel). Practicality of the procedure was demonstrated by measuring changes in anodic polarization behavior during high frequency current reversal cycles of 25 cycles per second with 1 mA/sq cm current density amplitude in solutions containing Cl anions. The results demonstrated that, due to excessive polarization which affects conductivity of barrier corrosion product layers, A36 was less resistant to atmospheric corrosion than its 4130 counterpart; behavior which was also demonstrated during exposure tests.

  7. Corrosion in a temperature gradient

    SciTech Connect

    Covino, Bernard S., Jr.; Holcomb, Gordon R.; Cramer, Stephen D.; Bullard, Sophie J.; Ziomek-Moroz, Margaret; White, M.L.

    2003-01-01

    High temperature corrosion limits the operation of equipment used in the Power Generation Industry. Some of the more destructive corrosive attack occurs on the surfaces of heat exchangers, boilers, and turbines where the alloys are subjected to large temperature gradients that cause a high heat flux through the accumulated ash, the corrosion product, and the alloy. Most current and past corrosion research has, however, been conducted under isothermal conditions. Research on the thermal-gradient-affected corrosion of various metals and alloys is currently being studied at the Albany Research Center’s SECERF (Severe Environment Corrosion and Erosion Research Facility) laboratory. The purpose of this research is to verify theoretical models of heat flux effects on corrosion and to quantify the differences between isothermal and thermal gradient corrosion effects. The effect of a temperature gradient and the resulting heat flux on corrosion of alloys with protective oxide scales is being examined by studying point defect diffusion and corrosion rates. Fick’s first law of diffusion was expanded, using irreversible thermodynamics, to include a heat flux term – a Soret effect. Oxide growth rates are being measured for the high temperature corrosion of cobalt at a metal surface temperature of 900ºC. Corrosion rates are also being determined for the high temperature corrosion of carbon steel boiler tubes in a simulated waste combustion environment consisting of O2, CO2, N2, and water vapor. Tests are being conducted both isothermally and in the presence of a temperature gradient to verify the effects of a heat flux and to compare to isothermal oxidation.

  8. Automated corrosion system in a moist environment

    SciTech Connect

    Hallman, R.L. Jr.; Calhoun, C.L.

    1999-03-19

    In an effort to assist researchers investigating the moisture-generated corrosion of metals and ceramics, a unique exposure system was developed. The initial goal of this system was to monitor corrosion ranging from a few monolayers at the outset of the corrosion process to high mass gains in more extensively corroded material. The new system uses a small robot arm for sample manipulation; gravimetric and Fourier transform infrared (FTIR) spectroscopy for corrosion-product determination; and a gas blending system to control the moisture content of the glove box in which the system is housed. The system's computer control can be configured to coordinate the examination of as many as 20 samples by periodic weighing and FTIR scanning. The computer also performs such functions as data logging of the temperature and pressure of the system and of the flow rate and moisture content of the purge gas. One main benefit of the computer-controlled robotic system is its ability to monitor samples 2 4 hours a day with precision control; this reduces problems stemming from human error or inconsistency of human technique.

  9. Wall thickness design and corrosion management

    SciTech Connect

    Gestel, W.M. van; Guijt, J.

    1994-12-31

    In 1995, Norske Shell will install two 36-in. sweet wet gas pipe lines in the Norwegian sector of the North Sea. The lines cross the Norwegian trench with water depths up to 350 meter. For the last 3.5 km. of the route the pipelines will be laid in a tunnel which will be flooded after construction. The two lines will transport largely untreated well fluids from the Troll field to an onshore processing plant at Kollsness, North of Bergen. From there sales gas will be transported to the continent via the Furopipe and Zeepipe systems. Gas contracts covering 30 years have been concluded with gas utilities on the continent. The maximum wall thickness that could be installed was limited by the capabilities of the present generation of lay barges and pipe mill capacities. The over-thickness, i.e. beyond that what is required for pressure containment and external collapse, is available as corrosion allowance. The paper discusses a novel probabilistic approach to define the corrosion control measures. The corrosion control system is based on the injection of glycol for corrosion mitigation and inspection by ultrasonic internal smart pigs, which in combination with identified fall back options, ensure a minimum 50 year service life.

  10. Case histories of external microbiologically influenced corrosion underneath disbonded coatings

    SciTech Connect

    Pikas, J.L.

    1996-08-01

    External microbiological influenced corrosion (MIC) underneath disbanded pipeline coating systems is a serious dilemma in the industry. In the past and even today, it has not been recognized as such because it has been primarily mistaken for galvanic corrosion. Due to the type of coating materials used in the past, the cleaning process or lack of it, and application methods used, all coating systems have the propensity to develop defects and pinholes where disbandment and this type of microbial corrosion could occur. In addition, the pipeline may or may not have had cathodic protection initially and/or consistently applied. Given these factors and the interaction of bacteria from the soil, moisture availability, and temperature of the pipeline, this paper will discuss the role that microbes play in the disbandment process, thus resulting in corrosion of an underground pipeline. Several case histories, laboratory results, and field findings will be presented.

  11. Space Shuttle Orbiter corrosion history, 1981-1993: A review and analysis of issues involving structures and subsystems

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This report summarizes past corrosion issues experienced by the NASA space shuttle orbiter fleet. Design considerations for corrosion prevention and inspection methods are reviewed. Significant corrosion issues involving structures and subsystems are analyzed, including corrective actions taken. Notable successes and failures of corrosion mitigation systems and procedures are discussed. The projected operating environment used for design is contrasted with current conditions in flight and conditions during ground processing.

  12. Corrosion Protection of Aluminum

    DOEpatents

    Dalrymple, R. S.; Nelson, W. B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred.

  13. CORROSION PROTECTION OF ALUMINUM

    DOEpatents

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  14. Corrosion resistant coating

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.; Thompson, K.G.; Bryan, C.J.

    1997-08-19

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  15. Corrosion resistant coating

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  16. Papering Over Corrosion

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Kennedy Space Center's battle against corrosion led to a new coating that was licensed to GeoTech and is commercially sold as Catize. The coating uses ligno sulfonic acid doped polyaniline (Ligno-Pani), also known as synthetic metal. Ligno-Pani can be used to extend the operating lives of steel bridges as one example of its applications. future applications include computers, televisions, cellular phones, conductive inks, and stealth technology.

  17. Stress Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.

  18. Corrosive resistant heat exchanger

    DOEpatents

    Richlen, Scott L.

    1989-01-01

    A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

  19. Corrosion risk assessment and risk based inspection for sweet oil and gas corrosion -- Practical experience

    SciTech Connect

    Pursell, M.J.; Sehnan, C.; Naen, M.F.

    1999-11-01

    Successful and cost effective Corrosion Risk Assessment depends on a sensible use of prediction methods and good understanding of process factors. Both are discussed with examples. Practice semi-probabilistic Risk Based Inspection planning methods that measure risk directly as cost and personnel hazard are compared with traditional methods and discussed.

  20. Corrosion in supercritical fluids

    SciTech Connect

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  1. Corrosion detection by induction

    NASA Astrophysics Data System (ADS)

    Roddenberry, Joshua L.

    Bridges in Florida are exposed to high amounts of humidity due to the state's geography. This excess moisture results in a high incidence of corrosion on the bridge's steel support cables. Also, the inclusion of ineffective waterproofing has resulted in additional corrosion. As this corrosion increases, the steel cables, responsible for maintaining bridge integrity, deteriorate and eventually break. If enough of these cables break, the bridge will experience a catastrophic failure resulting in collapse. Repairing and replacing these cables is very expensive and only increases with further damage. As each of the cables is steel, they have strong conductive properties. By inducing a current along each group of cables and measuring its dissipation over distance, a picture of structural integrity can be determined. The purpose of this thesis is to prove the effectiveness of using electromagnetic techniques to determine cable integrity. By comparing known conductive values (determined in a lab setting) to actual bridge values, the tester will be able to determine the location and severity of any damage, if present.

  2. Corrosion inhibitors from expired drugs.

    PubMed

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%.

  3. Corrosion of copper and lead containing materials by diesel lubricants

    SciTech Connect

    Cusano, C.M.; Wang, J.C.

    1995-01-01

    Corrosion of bearings, bushings, and roller follower pins by lubricants is traditionally minor except when the lubricant is severely degraded or contaminated. However, it has been found recently that many diesel lubricants induce a slow corrosion process which eventually leads to engine failures at a mileage that is high but still within the warranty period. A corrosion bench test has been developed to correlate with an extensive fleet database. Mechanism studies have been performed using this corrosion test. It is found that the corrosion of copper is due to the formation of copper sulfide, which is a result of the interactions between the copper and the sulfur-containing materials in the lubricant. The corrosion of lead is caused by the residual chlorine compounds in some of the lubricants. Some corrosion of tin has also been observed from a specific additive. Reducing the chlorine content and inhibiting the sulfur reactivity in the lubricants are essential to achieve acceptable engine durability. 10 refs., 1 fig., 8 tabs.

  4. Identification of Corrosion Products Due to Seawater and Fresh Water

    NASA Astrophysics Data System (ADS)

    Gismelseed, A.; Elzain, M.; Yousif, A.; Al Rawas, A.; Al-Omari, I. A.; Widatallah, H.; Rais, A.

    2004-12-01

    Mössbauer and X-ray diffraction (XRD) measurements were performed on corrosion products extracted from the inner surface of two different metal tubes used in a desalination plant in Oman. One of the tubes corroded due to the seawater while the second was corroded due to fresh water. The corrosion products thus resulted due to seawater were scrapped off in to two layers, the easily removable rust from the top is termed outer surface corrosion product and the strongly adhered rust as internal corrosion product. The Mössbauer spectra together with the XRD pattern of the outer surface showed the presence of magnetite (Fe3O4), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), goethite (α-FeOOH) and hematite (Fe2O3). The inner surface however showed the presence of akaganite, goethite, and magnetite. On the other hand, the corrosion products due to the fresh water showed only the presence of goethite and magnetite. The mechanism of the corrosion process will be discussed based on the significant differences between the formation of the iron components of the corrosion products due to seawater and the fresh water.

  5. The corrosive nature of manganese in drinking water.

    PubMed

    Alvarez-Bastida, C; Martínez-Miranda, V; Vázquez-Mejía, G; Solache-Ríos, M; Fonseca-Montes de Oca, G; Trujillo-Flores, E

    2013-03-01

    Corrosion problems having to do with drinking water distribution systems are related to many processes and factors and two of them are ionic acidity and carbon dioxide, which were considered in this work. The corrosion character of water is determined by the corrosion indexes of Langelier, Ryznar, Larson, and Mojmir. The results show that pipes made of different materials, such as plastics or metals, are affected by corrosion, causing manganese to be deposited on materials and dissolved in water. The deterioration of the materials, the degree of corrosion, and the deposited corrosion products were determined by X-ray diffraction and Scanning Electron Microscopy. High levels of manganese and nitrate ions in water may cause serious damage to the health of consumers of water. Three wells were examined, one of them presented a high content of manganese; the others had high levels of nitrate ions, which increased the acidity of the water and, therefore, the amount of corrosion of the materials in the distribution systems.

  6. Corrosion behavior of engineering alloys in synthetic wastewater

    NASA Astrophysics Data System (ADS)

    Sandoval-Jabalera, R.; Arias-Del Campo, E.; Chacón-Nava, J. G.; Martínez-Villafañe, A.; Malo-Tamayo, J. M.; Mora-Mendoza, J. L.

    2006-02-01

    The corrosion behavior of 1018, 410, and 800 steels exposed to synthetic wastewater have been studied using linear polarization resistance, cyclic potentiodynamic curves (CPCs), electrochemical noise (EN), and electrochemical impedance spectroscopy (EIS) tests. The conditions were: a biochemical oxygen demand of 776 ppm; a chemical oxygen demand of 1293 ppm; a pH of 8; and a cell temperature of 25 °C. From the CPC and EN results, no localized corrosion was found for the stainless steels. However, small indications of a possible localized corrosion process were detected for the 1018 steel. The EIS results revealed that different corrosion mechanisms occurred in the carbon steel compared with the stainless steels. The results show that the corrosion mechanism strongly depends on the type of steel. Overall, the 1018 steel exhibited the highest corrosion rate, followed by the 410 alloy. The highest corrosion resistance was achieved by the 800 alloy. In addition, scanning electron microscopy analyses were carried out to explain the experimental findings.

  7. A Monitoring Method Based on FBG for Concrete Corrosion Cracking.

    PubMed

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-07-14

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure.

  8. A Monitoring Method Based on FBG for Concrete Corrosion Cracking

    PubMed Central

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-01-01

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure. PMID:27428972

  9. A Monitoring Method Based on FBG for Concrete Corrosion Cracking.

    PubMed

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-01-01

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure. PMID:27428972

  10. A laboratory study on metal corrosion by ammonia gas

    SciTech Connect

    Zhu, J.; Riskowski, G.L.; Mackie, R.I.

    1999-06-01

    The effects of aerial ammonia on metal corrosion was examined in this study. Tests were conducted using three environmentally controlled chambers at three different ammonia levels (0 ppm, 100 ppm, and 200 ppm). Four types of metal products (uncoated 1010 carbon steel, galvanized steel, Galvalume, and pure zinc) were evaluated for weight losses and corrosion rates over a two-month test period. The test results showed that aerial ammonia, instead of accelerating metal corrosion, reduced the corrosion rates for steel. Weight losses for uncoated 1010 carbon steel samples in the chamber without ammonia were three and six times higher than those in chambers with ammonia levels of 100 ppm and 200 ppm, respectively. The corrosion rates were greatly reduced from 7.3 {micro}m/year to 1.2 {micro}m/year over the two-month period when ammonia level increased from 0 ppm to 200 ppm. For galvanized steel and pure zinc samples, the influence of ammonia on the corrosion processes was not apparent; however, there was a slight increase in corrosion rate for Galvalume samples with the increase of aerial ammonia concentrations.

  11. The corrosive nature of manganese in drinking water.

    PubMed

    Alvarez-Bastida, C; Martínez-Miranda, V; Vázquez-Mejía, G; Solache-Ríos, M; Fonseca-Montes de Oca, G; Trujillo-Flores, E

    2013-03-01

    Corrosion problems having to do with drinking water distribution systems are related to many processes and factors and two of them are ionic acidity and carbon dioxide, which were considered in this work. The corrosion character of water is determined by the corrosion indexes of Langelier, Ryznar, Larson, and Mojmir. The results show that pipes made of different materials, such as plastics or metals, are affected by corrosion, causing manganese to be deposited on materials and dissolved in water. The deterioration of the materials, the degree of corrosion, and the deposited corrosion products were determined by X-ray diffraction and Scanning Electron Microscopy. High levels of manganese and nitrate ions in water may cause serious damage to the health of consumers of water. Three wells were examined, one of them presented a high content of manganese; the others had high levels of nitrate ions, which increased the acidity of the water and, therefore, the amount of corrosion of the materials in the distribution systems. PMID:23376288

  12. Fracture mechanics and corrosion fatigue.

    NASA Technical Reports Server (NTRS)

    Mcevily, A. J.; Wei, R. P.

    1972-01-01

    Review of the current state-of-the-art in fracture mechanics, particularly in relation to the study of problems in environment-enhanced fatigue crack growth. The usefulness of this approach in developing understanding of the mechanisms for environmental embrittlement and its engineering utility are discussed. After a brief review of the evolution of the fracture mechanics approach and the study of environmental effects on the fatigue behavior of materials, a study is made of the response of materials to fatigue and corrosion fatigue, the modeling of the mechanisms of the fatigue process is considered, and the application of knowledge of fatigue crack growth to the prediction of the high cycle life of unnotched specimens is illustrated.

  13. Tuning the Internet for corrosion

    SciTech Connect

    Cottis, R.A.; Bogaerts, W.; Diamantidis, Z.

    1999-11-01

    The Internet provides a powerful, content-neutral mechanism for the presentation and delivery of information, but it has limitations for corrosion applications. These include the difficulty of defining corrosion specific information and the inability to accommodate commercial information. The Thematic Network described here is an open group project that aims to establish mechanisms for the indexing and exchange of corrosion information over the Internet.

  14. Embeddable sensor for corrosion measurement

    NASA Astrophysics Data System (ADS)

    Kelly, Robert G.; Yuan, J.; Jones, Stephen H.; Wang, W.; Hudson, K.; Sime, A.; Schneider, O.; Clemena, Gerardo G.

    1999-02-01

    The design of a microinstrument for corrosion monitoring in reinforced concrete is presented and the performance of the prototype device discussed. Sensors for the measurement of corrosion rate, corrosion potential, chloride concentration, and concrete conductivity have been developed and tested inside of model concrete slabs. The tests include electrochemical chloride driving as a method for test acceleration and wet/dry cycling. The corrosion rate and conductivity sensors perform very well, as do all aspects of the electronics. Work continues on the chloride sensor and reference electrode.

  15. Electrochemical Apparatus Simulates Corrosion In Crevices

    NASA Technical Reports Server (NTRS)

    Khoshbin, S. Rachel; Jeanjaquet, S. L.; Lumsden, Jesse B.

    1996-01-01

    Method of testing metal specimens for susceptibility to galvanic corrosion in crevices involves use of relatively simple electrochemical apparatus. By following method, one quantifies rates of corrosion of dissimilar-metal couples exposed to various etchants or other corrosive solutions.

  16. Corrosion and mechanical behavior of materials for coal gasification applications

    SciTech Connect

    Natesan, K.

    1980-05-01

    A state-of-the-art review is presented on the corrosion and mechanical behavior of materials at elevated temperatures in coal-gasification environments. The gas atmosphere in coal-conversion processes are, in general, complex mixtures which contain sulfur-bearing components (H/sub 2/S, SO/sub 2/, and COS) as well as oxidants (CO/sub 2//CO and H/sub 2/O/H/sub 2/). The information developed over the last five years clearly shows sulfidation to be the major mode of material degradation in these environments. The corrosion behavior of structural materials in complex gas environments is examined to evaluate the interrelationships between gas chemistry, alloy chemistry, temperature, and pressure. Thermodynamic aspects of high-temperature corrosion processes that pertain to coal conversion are discussed, and kinetic data are used to compare the behavior of different commercial materials of interest. The influence of complex gas environments on the mechanical properties such as tensile, stress-rupture, and impact on selected alloys is presented. The data have been analyzed, wherever possible, to examine the role of environment on the property variation. The results from ongoing programs on char effects on corrosion and on alloy protection via coatings, cladding, and weld overlay are presented. Areas of additional research with particular emphasis on the development of a better understanding of corrosion processes in complex environments and on alloy design for improved corrosion resistance are discussed. 54 references, 65 figures, 24 tables.

  17. Electrochemical noise measurements of sustained microbially influenced pitting corrosion in a laboratory flow loop system.

    SciTech Connect

    Lin, Y. J.

    1999-01-13

    Because of the chaotic nature of the corrosion process and the complexity of the electrochemical noise signals that are generated, there is no generally accepted method of measuring and interpreting these signals that allows the consistent detection and identification of sustained localized pitting (SLP) as compared to general corrosion. We have reexamined electrochemical noise analysis (ENA) of localized corrosion using different hardware, signal collection, and signal processing designs than those used in conventional ENA techniques. The new data acquisition system was designed to identify and monitor the progress of SLP by analyzing the power spectral density (PSD) of the trend of the corrosion current noise level (CNL) and potential noise level (PNL). Each CNL and PNL data point was calculated from the root-mean- square value of the ac components of current and potential fluctuation signals, which were measured simultaneously during a short time period. The PSD analysis results consistently demonstrated that the trends of PNL and CNL contain information that can be used to differentiate between SLP and general corrosion mechanisms. The degree of linear slope in the low-frequency portion of the PSD analysis was correlated with the SLP process. Laboratory metal coupons as well as commercial corrosion probes were tested to ensure the reproducibility and consistency of the results. The on-line monitoring capability of this new ENA method was evaluated in a bench-scale flow-loop system, which simulated microbially influenced corrosion (MIC) activity. The conditions in the test flow-loop system were controlled by the addition of microbes and different substrates to favor accelerated corrosion. The ENA results demonstrated that this in-situ corrosion monitoring system could effectively identify SLP corrosion associated with MIC, compared to a more uniform general corrosion mechanism. A reduction in SLP activity could be clearly detected by the ENA monitoring system

  18. The influence of temperature on the corrosion resistance of 10# carbon steel for refinery heat exchanger tubes

    NASA Astrophysics Data System (ADS)

    Xiu-qing, Xu; Zhen-quan, Bai; Yao-rong, Feng; Qiu-rong, Ma; Wen-zhen, Zhao

    2013-09-01

    Based on the corrosion problem of refinery heat exchanger tubes (10# carbon steel) in the course of using, the corrosion and electrochemical behaviors of 10# carbon steel in saline wastewater were investigated by means of autoclave test and electrochemical methods, respectively. The experiment results explained the formation mechanism of corrosion products film and indicated that the corrosion process of 10# steel in the corrosion medium with different temperature was divided into two parts: one was the formation of corrosion products below 50 ̊C, the other was the formation and dissolution of corrosion products film. The corrosion rate reached the maximum of 0.195 mm/a when the medium temperature was 60 ̊C.

  19. Corrosion control in alkanolamine gas treating: Absorber corrosion

    SciTech Connect

    Helle, H.P.E.

    1995-12-01

    Even in 1980, when corrosion in alkanolamine units was rampant, over 50% of all acid gas purification systems was based on alkanolamine absorbents. Over the years the control of corrosion has gradually become firmer. This paper examines the reasons for corrosion and provides insight in one particular aspect of corrosion in alkanolamine units, absorber corrosion. Three factors are identified, solvent degradation, local stagnancy and exceeding the units capacity. Solvent degradation increases the corrosivity of the solvent proper by the formation of complexing compounds such as diamines. Local stagnancy allows the solvent loading level to approach equilibrium which creates a corrosive environment. Exceeding the unit`s capacity will achieve essentially the same but on a larger scale. The corrosion enhancement by interaction of a total of 12 factors is made visual and clarified. The paper examines step by step the means to prevent a number of the factors arising. Guidelines are given for design of the absorber and absorber internals, the molarity of the solvent, inhibition and the benefits and handicaps of filming inhibitors.

  20. Corrosion and stress corrosion problems associated with the Space Shuttle.

    NASA Technical Reports Server (NTRS)

    Williamson, J. G.

    1971-01-01

    The problems encountered and the methods used to prevent corrosion and stress corrosion cracking on current space vehicles and aircraft are discussed. Preventing these problems on the Space Shuttle, in particular, by properly using materials that are highly resistant to this phenomenon, is examined in detail.

  1. Alloys For Corrosive, Hydrogen-Rich Environments

    NASA Technical Reports Server (NTRS)

    Mcpherson, William B.; Bhat, Biliyar N.; Chen, Po-Shou; Kuruvilla, A. K.; Panda, Binayak

    1993-01-01

    "NASA-23" denotes class of alloys resisting both embrittlement by hydrogen and corrosion. Weldable and castable and formed by such standard processes as rolling, forging, and wire drawing. Heat-treated to obtain desired combinations of strength and ductility in ranges of 100 to 180 kpsi yield strength, 120 to 200 kpsi ultimate tensile strength, and 10 to 30 percent elongation at break. Used in place of most common aerospace structural alloy, Inconel(R) 718.

  2. Corrosion resistance of premodeled wires made of stainless steel used for heart electrotherapy leaders

    NASA Astrophysics Data System (ADS)

    Przondziono, J.; Walke, W.; Młynarski, R.; Szatka, W.

    2012-05-01

    The purpose of the study is to evaluate resistance to electrochemical corrosion of wire made of X10CrNi18-8 stainless steel designed for use in cardiology treatment. The influence of strain formed in the premodeling process and methods of wire surface preparation to corrosive resistance in artificial plasma solution were analysed. Wire corrosion tests were carried out in the solution of artificial plasma. Resistance to electrochemical corrosion was evaluated on the ground of recorded curves of anodic polarization by means of potentiodynamic method. Potentiodynamic tests carried out enabled to determine how the resistance to pitting corrosion of wire changes, depending on strain formed in the premodeling process as well as on the method of wire surface preparation. For evaluation of phenomena occurring on the surface of tested steel, electrochemical impedance spectroscopy (EIS) was applied. Deterioration of corrosive properties of wire along with the increase in the formed strain hardening was observed.

  3. Study of biofilm influenced corrosion on cast iron pipes in reclaimed water

    NASA Astrophysics Data System (ADS)

    Zhang, Haiya; Tian, Yimei; Wan, Jianmei; Zhao, Peng

    2015-12-01

    Biofilm influenced corrosion on cast iron pipes in reclaimed water was systemically studied using the weight loss method and electrochemical impedance spectroscopy (EIS). The results demonstrated that compared to sterile water, the existence of the biofilm in reclaimed water promoted the corrosion process significantly. The characteristics of biofilm on cast iron coupons were examined by the surface profiler, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The bacterial counts in the biofilm were determined using the standard plate count method and the most probable number (MPN). The results demonstrated that the corrosion process was influenced by the settled bacteria, EPS, and corrosion products in the biofilm comprehensively. But, the corrosion mechanisms were different with respect to time and could be divided into three stages in our study. Furthermore, several corresponding corrosion mechanisms were proposed for different immersion times.

  4. ELECTROCHEMICAL STUDIES ON THE CORROSION OF CARBON STEEL IN OXALIC ACID CLEANING SOLUTIONS

    SciTech Connect

    Wiersma, B; John Mickalonis, J

    2007-10-08

    The Savannah River Site (SRS) will disperse or dissolve precipitated metal oxides as part of radioactive waste tank closure operations. Previously SRS has utilized oxalic acid to accomplish this task. Since the waste tanks are constructed of carbon steel, a significant amount of corrosion may occur. Although the total amount of corrosion may be insignificant for a short contact time, a significant amount of hydrogen may be generated due to the corrosion reaction. Linear polarization resistance and anodic/cathodic polarization tests were performed to investigate the corrosion behavior during the process. The effect of process variables such as temperature, agitation, aeration, sample orientation, light as well as surface finish on the corrosion behavior were evaluated. The results of the tests provided insight into the corrosion mechanism for the iron-oxalic acid system.

  5. The mechanism of borosilicate glass corrosion revisited

    NASA Astrophysics Data System (ADS)

    Geisler, Thorsten; Nagel, Thorsten; Kilburn, Matt R.; Janssen, Arne; Icenhower, Jonathan P.; Fonseca, Raúl O. C.; Grange, Marion; Nemchin, Alexander A.

    2015-06-01

    Currently accepted mechanistic models describing aqueous corrosion of borosilicate glasses are based on diffusion-controlled hydrolysis, hydration, ion exchange reactions, and subsequent re-condensation of the hydrolyzed glass network, leaving behind a residual hydrated glass or gel layer. Here, we report results of novel oxygen and silicon isotope tracer experiments with ternary Na borosilicate glasses that can be better explained by a process that involves the congruent dissolution of the glass, which is spatially and temporally coupled to the precipitation and growth of an amorphous silica layer at an inwardly moving reaction interface. Such a process is thermodynamically driven by the solubility difference between the glass and amorphous silica, and kinetically controlled by glass dissolution reactions at the reaction front, which, in turn, are controlled by the transport of water and solute elements through the growing corrosion zone. Understanding the coupling of these reactions is the key to understand the formation of laminar or more complex structural and chemical patterns observed in natural corrosion zones of ancient glasses. We suggest that these coupled processes also have to be considered to realistically model the long-term performance of silicate glasses in aqueous environments.

  6. Electrochemical impedance spectroscopy study on corrosion inhibition of benzyltriethylammonium chloride

    NASA Astrophysics Data System (ADS)

    Idris, Mohd Nazri; Daud, Abdul Razak; Othman, Norinsan Kamil

    2013-11-01

    Electrochemical Impedance Spectroscopy (EIS) was employed to study the corrosion inhibition behavior of benzyltriethylammonium chloride (BTC) for carbon steel corrosion. The inhibition efficiency was investigated in 1.0 M HCl solution at room temperature (25°C) by varying the BTC concentration. EIS results indicated that the double layer capacitance of electrolyte/carbon steel interface decreases with the increasing of BTC concentration and consequently enhances the polarization resistance of equivalence Randles circuit. The results indicated that inhibition efficiency of as high as 65% could be achieved when 10mM BTC was present in 1.0 M HCl solution as compared to inhibitor-free solution. The inhibition process of BTC on the carbon steel corrosion was found to obey Langmuir adsorption isotherm. This study revealed that BTC is suitable to be used as a corrosion inhibitor in acid media.

  7. Mechanisms for the atmospheric corrosion of carbonate stone

    SciTech Connect

    Graedel, T.E.

    2000-03-01

    The physical and chemical phenomena responsible for the atmospheric corrosion of carbonate stone are presented. Corrosion product formation, morphology, and chemical makeup are discussed in the context of calcium-containing minerals and other crystalline structures that thermodynamics and kinetics suggest are likely to be present. Formation pathways for the minerals most often reported to occur in carbonate corrosion layers are shown in schematic diagrams. The dominant corrosion products are sulfates and oxalates, the former resulting from interactions with atmospheric sulfur dioxide or sulfate ions, the latter from oxalate secretions from the biological organisms. present (and perhaps to some extent from oxalate deposited from the atmosphere). The degradation processes are enhanced by the catalytic action of transition metal ions present in the stone and of soot deposited from the atmosphere.

  8. Corrosion inhibition by control of gas composition during mist drilling

    SciTech Connect

    Hinkebein, T.E.; Snyder, T.L.

    1981-05-01

    Chemical compositional specifications have been generated for inert gases which reduce drill string corrosion when used in conjunction with mist drilling processes. These specifications are based on the assumption that the corrosion rate is dependent on the dissolved gaseous species concentrations. Data taken both from the literature and from a mist drilling field test with nitrogen in Valle Grande, NM, relate corrosion rates to fluid compositions. These solution compositions are then associated with gas phase compositions using equilibrium data available from the literature and material balances. Two sources of gas were considered: cryogenically purified nitrogen from air and exhaust gas from a diesel engine, which contain (in addition to N/sub 2/ and O/sub 2/) CO/sub 2/, NO/sub x/, SO/sub 2/, H/sub 2/O, and CO. A maximum concentration of 50 ppM O/sub 2/ in the gas phase is recommended to alleviate pitting corrosion.

  9. A molecular interpretation of stress corrosion in silica

    NASA Astrophysics Data System (ADS)

    Michalske, Terry A.; Freiman, Stephen W.

    1982-02-01

    The mechanical strength of many glasses and ceramic materials decreases with time under static loading and ambient environments. This strength loss is associated with slow growth of pre-existing surface flaws due to a stress-corrosion process. To make long-term strength predictions for ceramic components, it is important to understand the stress-corrosion mechanism. We have studied stress corrosion in vitreous silica exposed to water and several non-aqueous environments and report here that environments which enhance stress corrosion are composed of molecular groups with electron donor sites on one end and proton donor sites at the other. These results suggest a detailed chemical model for the interaction of the environment with mechanically strained bonds in the solid at the tip of a crack. The proposed model also has implications for the long-term strength behaviour of a wide variety of brittle materials.

  10. Electrochemical and Mechanical Behavior of Lead-Silver and Lead-Bismuth Casting Alloys for Lead-Acid Battery Components

    NASA Astrophysics Data System (ADS)

    Osório, Wislei R.; Peixoto, Leandro C.; Garcia, Amauri

    2015-09-01

    The present study focuses on the interrelation of microstructure, mechanical properties, and corrosion resistance of Pb-Ag and Pb-Bi casting alloys, which can be used in the manufacture of lead-acid battery components, as potential alternatives to alloys currently used. A water-cooled solidification system is used, in which vertical upward directional solidification is promoted permitting a wide range of microstructures to be investigated. Correlations between microstructural arrays, tensile strengths, and corrosion resistances of Pb-1 wt pct Ag, Pb-2.5 wt pct Ag, Pb-1 wt pct Bi, and Pb-2.5 wt pct Bi alloys are envisaged. It is shown that a compromise between corrosion resistance (represented by the corrosion current density) and mechanical properties (represented by the ultimate tensile strength) can be obtained. Comparisons between specific strengths and mechanical/corrosion ratios are also made. It is also shown that, for microstructures solidified under cooling rates higher than 10 K/s, the Pb-Ag alloys exhibit higher specific strength and mechanical/corrosion ratio. In contrast, for casting processes in which the cooling rates are lower than 5 K/s, the dilute Pb-Bi alloy ( i.e., 1 wt pct Bi) is shown to have more appropriate requirements for lead-acid battery components. Comparisons between specific strengths, mechanical/corrosion ratio, and relative weight and cost with Pb-Sn and Pb-Sb alloys are also made.

  11. Process technology and effects of spallation products: Circuit components, maintenance, and handling

    SciTech Connect

    Sigg, B.; Haines, S.J.; Dressler, R.; McManamy, T.

    1996-06-01

    Working Session D included an assessment of the status of the technology and components required to: (1) remove impurities from the liquid metal (mercury or Pb-Bi) target flow loop including the effects of spallation products, (2) provide the flow parameters necessary for target operations, and (3) maintain the target system. A series of brief presentations were made to focus the discussion on these issues. The subjects of these presentations, and presenters were: (1) Spallation products and solubilities - R. Dressler; (2) Spallation products for Pb-Bi - Y. Orlov; (3) Clean/up/impurity removal components - B. Sigg; (4) {open_quotes}Road-Map{close_quotes} and remote handling needs - T. McManamy; (5) Remote handling issues and development - M. Holding. The overall conclusion of this session was that, with the exception of (i) spallation product related processing issues, (ii) helium injection and clean-up, and (iii) specialized remote handling equipment, the technology for all other circuit components (excluding the target itself) exists. Operating systems at the Institute of Physics in Riga, Latvia (O. Lielausis) and at Ben-Gurion University in Beer Shiva, Israel (S. Lesin) have demonstrated that other liquid metal circuit components including pumps, heat exchangers, valves, seals, and piping are readily available and have been reliably used for many years. In the three areas listed above, the designs and analysis are not judged to be mature enough to determine whether and what types of technology development are required. Further design and analysis of the liquid metal target system is therefore needed to define flow circuit processing and remote handling equipment requirements and thereby identify any development needs.

  12. INHIBITION OF CORROSION

    DOEpatents

    Atherton, J.E. Jr.; Gurinsky, D.H.

    1958-06-24

    A method is described for preventing corrosion of metallic container materials by a high-temperature liquid bismuth flowing therein. The method comprises fabricating the containment means from a steel which contains between 2 and 12% chromium, between 0.5 and 1.5% of either molybdenum and silicon, and a minimum of nickel and manganese, and maintaining zirconium dissolved in the liquid bismuth at a concentration between 50 parts per million and its saturation value at the lowest temperature in the system.

  13. DPC materials and corrosion environments.

    SciTech Connect

    Ilgen, Anastasia Gennadyevna; Bryan, Charles R.; Teich-McGoldrick, Stephanie; Hardin, Ernest; Clarity, J.

    2014-10-01

    After an exposition of the materials used in DPCs and the factors controlling material corrosion in disposal environments, a survey is given of the corrosion rates, mechanisms, and products for commonly used stainless steels. Research needs are then identified for predicting stability of DPC materials in disposal environments. Stainless steel corrosion rates may be low enough to sustain DPC basket structural integrity for performance periods of as long as 10,000 years, especially in reducing conditions. Uncertainties include basket component design, disposal environment conditions, and the in-package chemical environment including any localized effects from radiolysis. Prospective disposal overpack materials exist for most disposal environments, including both corrosion allowance and corrosion resistant materials. Whereas the behavior of corrosion allowance materials is understood for a wide range of corrosion environments, demonstrating corrosion resistance could be more technically challenging and require environment-specific testing. A preliminary screening of the existing inventory of DPCs and other types of canisters is described, according to the type of closure, whether they can be readily transported, and what types of materials are used in basket construction.

  14. Atlas 5013 tank corrosion test

    NASA Technical Reports Server (NTRS)

    Sutherland, W. M.; Girton, L. D.; Treadway, D. G.

    1978-01-01

    The type and cause of corrosion in spot welded joints were determined by X-ray and chemical analysis. Fatigue and static tests showed the degree of degradation of mechanical properties. The corrosion inhibiting effectiveness of WD-40 compound and required renewal period by exposing typical joint specimens were examined.

  15. INTERNAL CORROSION AND DEPOSITION CONTROL

    EPA Science Inventory

    Corrosion is one of the most important problems in the drinking water industry. It can affect public health, public acceptance of a water supply, and the cost of providing safe water. Deterioration of materials resulting from corrosion can necessitate huge yearly expenditures o...

  16. Agricultural Polymers as Corrosion Inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural polymers were composed of extra-cellular polysaccharides secreted by Leuconostoc mesenteroides have been shown to inhibit corrosion on corrosion-sensitive metals. The substantially pure exopolysaccharide has a general structure consisting of alpha(1-6)-linked D-glucose backbone and appr...

  17. Understanding the operation and use of high temperature electrochemical corrosion rate probes

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, M.; Cayard, Michael S.; Eden, David A.

    2004-01-01

    Electrochemical corrosion rate probes were constructed and tested along with mass loss coupons in a N2/O2/CO2 plus water vapor environment. Temperatures ranged from 450 to 600 C. Corrosion rates for ash-covered mild steel, 304L SS, and 316L SS probes using electrochemical techniques were a function of time, temperature, and process environment. Correlation between electrochemical and mass loss corrosion rates was good.

  18. Prediction of Corrosion of Alloys in Mixed-Solvent Environments

    SciTech Connect

    Anderko, Andrzej; Wang, Peiming; Young, Robert D.; Riemer, Douglas P.; McKenzie, Patrice; Lencka, Malgorzata M.; Babu, Sudarsanam Suresh; Angelini, Peter

    2003-06-05

    Corrosion is much less predictable in organic or mixed-solvent environments than in aqueous process environments. As a result, US chemical companies face greater uncertainty when selecting process equipment materials to manufacture chemical products using organic or mixed solvents than when the process environments are only aqueous. Chemical companies handle this uncertainty by overdesigning the equipment (wasting money and energy), rather than by accepting increased risks of corrosion failure (personnel hazards and environmental releases). Therefore, it is important to develop simulation tools that would help the chemical process industries to understand and predict corrosion and to develop mitigation measures. To create such tools, we have developed models that predict (1) the chemical composition, speciation, phase equilibria, component activities and transport properties of the bulk (aqueous, nonaqueous or mixed) phase that is in contact with the metal; (2) the phase equilibria and component activities of the alloy phase(s) that may be subject to corrosion and (3) the interfacial phenomena that are responsible for corrosion at the metal/solution or passive film/solution interface. During the course of this project, we have completed the following: (1) Development of thermodynamic modules for calculating the activities of alloy components; (2) Development of software that generates stability diagrams for alloys in aqueous systems; these diagrams make it possible to predict the tendency of metals to corrode; (3) Development and extensive verification of a model for calculating speciation, phase equilibria and thermodynamic properties of mixed-solvent electrolyte systems; (4) Integration of the software for generating stability diagrams with the mixed-solvent electrolyte model, which makes it possible to generate stability diagrams for nonaqueous or mixed-solvent systems; (5) Development of a model for predicting diffusion coefficients in mixed-solvent electrolyte

  19. CORROSION TESTING IN SIMULATED TANK SOLUTIONS

    SciTech Connect

    Hoffman, E.

    2010-12-09

    surface, efforts are needed to compare the polished surfaces to corroded and mill-scale surfaces, which are more likely to occur in application. Additionally, due to the change in liquid waste levels within the tanks, salt deposits are highly likely to be present along the tank wall. When the level of the tank decreases, a salt deposit will form as the solution evaporates. The effects of this pre-existing salt, or supernate deposit, are unknown at this time on the corrosion effect and thus require investigation. Additionally, in the presence of radiation, moist air undergoes radiolysis, forming a corrosive nitric acid condensate. This condensate could accelerate the corrosion process in the vapor space. To investigate this process, an experimental apparatus simulating the effects of radiation was designed and constructed to provide gamma irradiation while coupons are exposed to a simulate tank solution. Additionally, ammonia vapors will also be introduced to further represent the tank environment.

  20. Electrochemical studies of corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The effect of single salts, as well as multicomponent mixtures, on corrosion inhibition was studied for type 1010 steel; for 5052, 1100, and 2219-T87 aluminum alloys; and for copper. Molybdate-containing inhibitors exhibit an immediate, positive effect for steel corrosion, but an incubation period may be required for aluminum before the effect of a given inhibitor can be determined. The absence of oxygen was found to provide a positive effect (smaller corrosion rate) for steel and copper, but a negative effect for aluminum. This is attributed to the two possible mechanisms by which aluminum can oxidize. Corrosion inhibition is generally similar for oxygen-rich and oxygen-free environments. The results show that the electrochemical method is an effective means of screening inhibitors for the corrosion of single metals, with caution to be exercised in the case of aluminum.

  1. Corrosion of Titanium Matrix Composites

    SciTech Connect

    Covino, B.S., Jr.; Alman, D.E.

    2002-09-22

    The corrosion behavior of unalloyed Ti and titanium matrix composites containing up to 20 vol% of TiC or TiB{sub 2} was determined in deaerated 2 wt% HCl at 50, 70, and 90 degrees C. Corrosion rates were calculated from corrosion currents determined by extrapolation of the tafel slopes. All curves exhibited active-passive behavior but no transpassive region. Corrosion rates for Ti + TiC composites were similar to those for unalloyed Ti except at 90 degrees C where the composites were slightly higher. Corrosion rates for Ti + TiB{sub 2} composites were generally higher than those for unalloyed Ti and increased with higher concentrations of TiB{sub 2}. XRD and SEM-EDS analyses showed that the TiC reinforcement did not react with the Ti matrix during fabrication while the TiB{sub 2} reacted to form a TiB phase.

  2. pH Sensitive Microcapsules for Delivery of Corrosion Inhibitors

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2006-01-01

    A considerable number of corrosion problems can be solved by coatings. However, even the best protective coatings can fail by allowing the slow diffusion of oxygen and moisture to the metal surface. Corrosion accelerates when a coating delaminates. Often, the problems start when microscopic nicks or pits on the surface develop during manufacturing or through wear and tear. This problem can be solved by the incorporation of a self-healing function into the coating. Several new concepts are currently under development to incorporate this function into a coating. Conductive polymers, nanoparticles, and microcapsules are used to release corrosion-inhibiting ions at a defect site. The objective of this investigation is to develop a smart coating for the early detection and inhibition of corrosion. The dual function of this new smart coating system is performed by pH-triggered release microcapsules. The microcapsules can be used to deliver healing agents to terminate the corrosion process at its early stage or as corrosion indicators by releasing dyes at the localized corrosion sites. The dyes can be color dyes or fluorescent dyes, with or without pH sensitivity. Microcapsules were formed through the interfacial polymerization process. The average size of the microcapsules can be adjusted from 1 to 100 micron by adjusting the emulsion formula and the microcapsule forming conditions. A typical microcapsule size is around 10 microns with a narrow size distribution. The pH sensitivity of the microcapsule can also be controlled by adjusting the emulsion formula and the polymerization reaction time. Both corrosion indicator (pH indicator) and corrosion inhibitor containing microcapsules were formed and incorporated into paint systems. Test panels of selected steels and aluminum alloys were painted using these paints. Testing of compatibility between the microcapsule system and different paint systems are in progress. Initial experiments with the microcapsule containing paint

  3. The Underground Corrosion of Selected Type 300 Stainless Steels After 34 Years

    SciTech Connect

    T. S. Yoder; M. K. Adler Flitton

    2009-03-01

    Recently, interest in long-term underground corrosion has greatly increased because of the ongoing need to dispose of nuclear waste. Additionally, the Nuclear Waste Policy Act of 1982 requires disposal of high-level nuclear waste in an underground repository. Current contaminant release and transport models use limited available short-term underground corrosion rates when considering container and waste form degradation. Consequently, the resulting models oversimplify the complex mechanisms of underground metal corrosion. The complexity of stainless steel corrosion mechanisms and the processes by which corrosion products migrate from their source are not well depicted by a corrosion rate based on general attack. The research presented here is the analysis of austenitic stainless steels after 33½ years of burial. In this research, the corrosion specimens were analyzed using applicable ASTM standards as well as microscopic and X-ray examination to determine the mechanisms of underground stainless steel corrosion. As presented, the differences in the corrosion mechanisms vary with the type of stainless steel and the treatment of the samples. The uniqueness of the long sampling time allows for further understanding of the actual stainless steel corrosion mechanisms, and when applied back into predictive models, will assist in reduction of the uncertainty in parameters for predicting long-term fate and transport.

  4. [Corrosion of stainless steel 201, 304 and 316L in the simulated sewage pipes reactor].

    PubMed

    Bao, Guo-Dong; Zuo, Jian-E; Wang, Ya-Jiao; Gan, Li-Li

    2014-08-01

    The corrosion behavior of stainless steel 201, 304 and 316L which would be used as sewer in-situ rehabilitation materials was studied in the simulated sewage pipes reactor. The corrosion potential and corrosion rate of these three materials were studied by potentiodynamic method on the 7th, 14th, 21st, 56th day under two different conditions which were full immersion condition or batch immersion condition with a 2-day cycle. The electrode process was studied by Electrochemical Impedance Spectroscopy (EIS) on the 56th day. The microstructure and composition of the corrosion pitting were analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) on the 56th day. The results showed that 304 and 316L had much better corrosion resistance than 201 under both conditions. 304 and 316L had much smaller corrosion rate than 201 under both conditions. The corrosion resistance of all three kinds of stainless steel under the batch immersion condition was much better than those under the full immersion condition. The corrosion rate of all three kinds of stainless steel under the batch immersion condition was much smaller than those under the full immersion condition. Point pitting corrosion was formed on the surfaces of 304 and 316L. In comparison, a large area of corrosion was formed in the surface of 201.

  5. Characterization of corrosion scale formed on stainless steel delivery pipe for reclaimed water treatment.

    PubMed

    Cui, Yong; Liu, Shuming; Smith, Kate; Yu, Kanghua; Hu, Hongying; Jiang, Wei; Li, Yuhong

    2016-01-01

    To reveal corrosion behavior of stainless steel delivery pipe used in reclaimed water treatment, this research focused on the morphological, mineralogical and chemical characteristics of stainless steel corrosion scale and corroded passive film. Corrosion scale and coupon samples were taken from a type 304 pipe delivering reclaimed water to a clear well in service for more than 12 years. Stainless steel corrosion scales and four representative pipe coupons were investigated using mineralogy and material science research methods. The results showed corrosion scale was predominantly composed of goethite, lepidocrocite, hematite, magnetite, ferrous oxide, siderite, chrome green and chromite, the same as that of corroded pipe coupons. Hence, corrosion scale can be identified as podiform chromite deposit. The loss of chromium in passive film is a critical phenomenon when stainless steel passive film is damaged by localized corrosion. This may provide key insights toward improving a better comprehension of the formation of stainless steel corrosion scale and the process of localized corrosion. The localized corrosion behavior of stainless steel is directly connected with reclaimed water quality parameters such as residual chlorine, DO, Cl(-) and SO4(2-). In particular, when a certain amount of residual chlorine in reclaimed water is present as an oxidant, ferric iron is the main chemical state of iron minerals.

  6. Chemical Corrosion of Liquid-Phase Sintered SiC in Acidic/Alkaline Solutions Part 1. Corrosion in HNO3 Solution

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Zhang, Ming; He, Xinnong; Tang, Wenming

    2016-03-01

    The corrosion behavior of the liquid-phase sintered SiC (LPS-SiC) was studied by dipping in 3.53 mol/L HNO3 aqueous solution at room temperature and 70 °C, respectively. The weight loss, strength reduction and morphology evolution of the SiC specimens during corroding were revealed and also the chemical corrosion process and mechanism of the SiC specimens in the acidic solution were clarified. The results show that the corrosion of the LPS-SiC specimens in the HNO3 solution is selective. The SiC particles are almost free from corrosion, but the secondary phases of BaAl2Si2O8 (BAS) and Y2Si2O7 are corroded via an acid-alkali neutralization reaction. BAS has a higher corrosion rate than Y2Si2O7, resulting in the formation of the bamboo-leaf-like corrosion pits. As the SiC specimens etched in the HNO3 solution at room temperature for 75 days, about 80 μm thickness corrosion layer forms. The weight loss and bending strength reduction of the etched SiC specimens are 2.6 mg/cm2 and 52%, respectively. The corrosion of the SiC specimens is accelerated in the 70 °C HNO3 solution with a rate about five times bigger than that in the same corrosion medium at room temperature.

  7. Naval electrochemical corrosion reducer

    DOEpatents

    Clark, Howard L.

    1991-10-01

    A corrosion reducer for use with ships having a hull, a propeller mounted a propeller shaft and extending through the hull, bearings supporting the shaft, at least one thrust bearing and one seal. The improvement includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft in order to reduce corrosion due to electrolytic action. The current reduction assembly includes an electrical contact, the current collector, and the hull. The current reduction assembly further includes a device for sensing and measuring the voltage between the hull and the shaft and a device for applying a reverse voltage between the hull and the shaft so that the resulting voltage differential is from 0 to 0.05 volts. The current reduction assembly further includes a differential amplifier having a voltage differential between the hull and the shaft. The current reduction assembly further includes an amplifier and a power output circuit receiving signals from the differential amplifier and being supplied by at least one current supply. The current selector includes a brush assembly in contact with a slip ring over the shaft so that its potential may be applied to the differential amplifier.

  8. Monitoring of corrosion in ORGDP cylinder yards

    SciTech Connect

    Henson, H.M.; Barlow, C.R.; Frazier, J.L.; Ziehlke, K.T.

    1989-01-01

    Uranium hexafluoride (UF/sub 6/) throughout the nuclear fuel cycle is handled and stored in cylinders which are designed, manufactured, and maintained in accordance with the ASME Boiler and Pressure Vessel Code for unfired pressure vessels (Section VIII). There are presently more than 40,000 of these cylinders within the DOE Oak Ridge Operations complex currently used for the storage of isotopically depleted material (process tailings). These tails cylinders, in 10- and 14-ton sizes, are 48 inches in diameter and were originally constructed of steel ASTM A285, then since 1978 of steel ASTM A516. The corrosion and monitoring of corrosion of the cylinders is discussed. 8 refs., 6 figs.

  9. Survey updates amine stress corrosion cracking data

    SciTech Connect

    Not Available

    1992-01-13

    The final report by National Association of Corrosion Engineers (NACE) task group T-8-14 has been published, revising and expanding the information on stress information on stress corrosion cracking of carbon steel in diethanolamine and diisopropanolamine service. A major conclusion of the survey was that cracking frequency was more prevalent in monoethanolamine (MEA) than in other amines. This paper reports that further examination of the DEA data indicated that some units were previously in MEA service and the reported cracks were actually associated with that period. A detailed follow-up review of the DEA data also revealed that some cases were caused by processes other than amine cracking. In many cases, further inspection or testing had been done after the original survey was submitted.

  10. Corrosion Engineers and Nuclear Waste Disposition

    SciTech Connect

    Rebak, R B

    2006-07-13

    are clay, basalt, tuff and granite. The groundwater associated with the containers should all be relatively benign to most materials because of their low ionic strengths, near neutral pH, and low concentrations of halide ions. The corrosiveness of these waters could increase if significant vaporization occurs due to heating from radioactive decay during the early times of emplacement. Many different alloys are currently being studied for the container materials, including carbon steel, stainless steel, titanium, copper, and nickel alloys. Twenty years ago, most of the designs for repositories specified life spans of 300 to 1000 years. Today, some designs are considering lifetimes as high as 1,000,000 years. This requirement has created a difficult problem for engineers to solve. The unique aspect of this problem is associated with making predictions about the corrosion behavior of container materials for extended periods of time. Many of the alloy systems being considered have been in existence for less than 100 years. The understanding and methodologies of existing corrosion engineering remain largely oriented to traditional problems involving less corrosion resistant alloys and corrosion behavior over time periods less than decades. Predicting the behavior of engineering alloys over geologic time periods poses new challenges but at the same time offers new opportunities for the development of corrosion science. Even though nuclear energy has been in use for half a century, no country currently operates a nuclear waste repository. The current renaissance of public interest in nuclear energy may put some pressure on the development of the repositories. Building a nuclear waste repository is a long process since the whole society needs to be ready for it, and nowadays this society may extend beyond country lines. Corrosion engineers can help.

  11. Review of corrosion causes and corrosion control in a technical facility

    NASA Technical Reports Server (NTRS)

    Charng, T.; Lansing, F.

    1982-01-01

    Causes of corrosion of metals and their alloys are reviewed. The corrosion mechanism is explained by electrochemical reaction theory. The causes and methods of controlling of both physiochemical corrosion and biological corrosion are presented. Factors which influence the rate of corrosion are also discussed.

  12. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

    2011-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

  13. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.

    PubMed

    Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

    2011-06-01

    Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential. PMID:21290167

  14. Corrosion tests in brine and steam from the Salton Sea KGRA

    SciTech Connect

    Carter, J.P.; McCawley, F.X.

    1982-03-01

    The Bureau of Mines tested 13 alloys for resistance to general corrosion, pitting corrosion, and stress corrosion cracking in the brine and steam environments produced from geothermal well Magmamax 1 in the Salton Sea Known Geothermal Resources Area in California. The tests provided seven process environments. The alloys most resistant to corrosion in all environments were Inconel 625, Hastelloy C-276, and stainless steel alloy 29-4. Hastelloys G and S were highly resistant to all types of corrosion decreases with time. The stainless steel alloys 430, E-Brite 26-1, and 6X had good resistance to general corrosion but were susceptible to pitting. Unstressed type 316 L stainless steel exhibited severe cracking. The 1020 carbon and 4130 alloy steels were the least resistant.

  15. Current techniques in acid-chloride corrosion control and monitoring at The Geysers

    SciTech Connect

    Hirtz, Paul; Buck, Cliff; Kunzman, Russell

    1991-01-01

    Acid chloride corrosion of geothermal well casings, production piping and power plant equipment has resulted in costly corrosion damage, frequent curtailments of power plants and the permanent shut-in of wells in certain areas of The Geysers. Techniques have been developed to mitigate these corrosion problems, allowing continued production of steam from high chloride wells with minimal impact on production and power generation facilities.The optimization of water and caustic steam scrubbing, steam/liquid separation and process fluid chemistry has led to effective and reliable corrosion mitigation systems currently in routine use at The Geysers. When properly operated, these systems can yield steam purities equal to or greater than those encountered in areas of The Geysers where chloride corrosion is not a problem. Developments in corrosion monitoring techniques, steam sampling and analytical methodologies for trace impurities, and computer modeling of the fluid chemistry has been instrumental in the success of this technology.

  16. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.

    PubMed

    Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

    2011-06-01

    Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

  17. Corrosion in Reinforced Concrete Panels: Wireless Monitoring and Wavelet-Based Analysis

    PubMed Central

    Qiao, Guofu; Sun, Guodong; Hong, Yi; Liu, Tiejun; Guan, Xinchun

    2014-01-01

    To realize the efficient data capture and accurate analysis of pitting corrosion of the reinforced concrete (RC) structures, we first design and implement a wireless sensor and network (WSN) to monitor the pitting corrosion of RC panels, and then, we propose a wavelet-based algorithm to analyze the corrosion state with the corrosion data collected by the wireless platform. We design a novel pitting corrosion-detecting mote and a communication protocol such that the monitoring platform can sample the electrochemical emission signals of corrosion process with a configured period, and send these signals to a central computer for the analysis. The proposed algorithm, based on the wavelet domain analysis, returns the energy distribution of the electrochemical emission data, from which close observation and understanding can be further achieved. We also conducted test-bed experiments based on RC panels. The results verify the feasibility and efficiency of the proposed WSN system and algorithms. PMID:24556673

  18. Corrosion of NiTi Wires with Cracked Oxide Layer

    NASA Astrophysics Data System (ADS)

    Racek, Jan; Šittner, Petr; Heller, Luděk; Pilch, Jan; Petrenec, Martin; Sedlák, Petr

    2014-07-01

    Corrosion behavior of superelastic NiTi shape memory alloy wires with cracked TiO2 surface oxide layers was investigated by electrochemical corrosion tests (Electrochemical Impedance Spectroscopy, Open Circuit Potential, and Potentiodynamic Polarization) on wires bent into U-shapes of various bending radii. Cracks within the oxide on the surface of the bent wires were observed by FIB-SEM and TEM methods. The density and width of the surface oxide cracks dramatically increase with decreasing bending radius. The results of electrochemical experiments consistently show that corrosion properties of NiTi wires with cracked oxide layers (static load keeps the cracks opened) are inferior compared to the corrosion properties of the straight NiTi wires covered by virgin uncracked oxides. Out of the three methods employed, the Electrochemical Impedance Spectroscopy seems to be the most appropriate test for the electrochemical characterization of the cracked oxide layers, since the impedance curves (Nyquist plot) of differently bent NiTi wires can be associated with increasing state of the surface cracking and since the NiTi wires are exposed to similar conditions as the surfaces of NiTi implants in human body. On the other hand, the potentiodynamic polarization test accelerates the corrosion processes and provides clear evidence that the corrosion resistance of bent superelastic NiTi wires degrades with oxide cracking.

  19. Characterization of corrosion damage in prestressed concrete using acoustic emission

    NASA Astrophysics Data System (ADS)

    Mangual, Jesé; ElBatanouny, Mohamed K.; Vélez, William; Ziehl, Paul; Matta, Fabio; González, Miguel

    2012-04-01

    The corrosion of reinforced concrete structures is a major issue from both a structural safety and maintenance management point of view. Early detection of the internal degradation process provides the owner with sufficient options to develop a plan of action. An accelerated corrosion test was conducted in a small scale concrete specimen reinforced with a 0.5 inch (13 mm) diameter prestressing strand to investigate the correlation between corrosion rate and acoustic emission (AE). Corrosion was accelerated in the laboratory by supplying anodic current via a rectifier while continuously monitoring acoustic emission activity. Results were correlated with traditional electrochemical techniques such as half-cell potential and linear polarization. The location of the active corrosion activity was found through a location algorithm based on time of flight of the stress waves. Intensity analysis was used to plot the relative significance of the damage states present in the specimen and a preliminary grading chart is presented. Results indicate that AE may be a useful non-intrusive technique for the detection and quantification of corrosion damage.

  20. Fiber optic corrosion sensing for bridges and roadway surfaces

    NASA Astrophysics Data System (ADS)

    Fuhr, Peter L.; Ambrose, Timothy P.; Huston, Dryver R.; McPadden, Adam P.

    1995-04-01

    In this paper we report the development of a fiber optic corrosion sensing system that complements and/or surpasses the capabilities of conventional corrosion sensing techniques. The sensing system is based on evanescent wave phenomena and in the configured sensor allows for the detection of general corrosion on and within materials. Based on the authors' experience installing may kilometers of fiberoptic sensors into large civil structures such as multistory buildings, hydroelectric dams, and railway/roadway bridges, we are (currently) embedding these sensors into bridge test members -- limited structures that are being subjected to accelerated corrosion testing conditions. Three Vermont Agency of Transportation bridges, one in a low salt use region, one in a medium salt use region, and the third in a high salt use region, are being selected and will be instrumented with these embedded fiber optic corrosion sensors. Monitoring of chloride penetration and rebar corrosion status will be measured during the course of a longitudinal study. The specific sensing mechanism and design for robustness (to allow survival of the embedding process during repaving of the bridges) are discussed and laboratory and initial field results are presented.

  1. Dissolution and corrosion inhibition of copper, zinc, and their alloys

    SciTech Connect

    Jinturkar, P.; Guan, Y.C.; Han, K.N.

    1998-02-01

    The corrosion behavior of copper, zinc, and their alloys in sulfuric acid (H{sub 2}SO{sub 4}) solutions with oxygen and ferric ions (Fe{sup 3+}) was studied using a potentiostat. Oxygen and Fe{sup 3+} ions were shown to play an important role in corrosion of copper and copper-zinc alloys. Cathodic reduction of oxygen mainly was controlled by chemical reaction, and that of Fe{sup 3+} ions was controlled by diffusion. The overall cathodic process was the summation of the reduction of oxygen and Fe{sup 3+} ions. Corrosion of zinc was controlled mainly by reduction of water. Corrosion inhibition using benzotriazole (BTAH) also was investigated in aerated and deaerated solutions. BTAH was found to be a useful inhibitor, and the inhibition layer was shown to be stable and persistent. Morphology of the surface of copper, zinc, and brasses after corrosion in the presence and absence of BTAH was examined by scanning electron microscopy. BTAH formed a protective layer on the surface, thereby inhibiting corrosion. Solution analysis of the dissolution of brasses showed that zinc dissolved preferentially in the initial stages, followed by simultaneous dissolution of copper and zinc.

  2. Liquid Coatings for Reducing Corrosion of Steel in Concrete

    NASA Technical Reports Server (NTRS)

    MacDowell, Louis G.; Curran, Joseph

    2003-01-01

    Inorganic coating materials are being developed to slow or stop corrosion of reinforcing steel members inside concrete structures. It is much simpler and easier to use these coating materials than it is to use conventional corrosion-inhibiting systems based on impressed electric currents. Unlike impressed electrical corrosion-inhibiting systems, these coatings do not require continuous consumption of electrical power and maintenance of power-supply equipment. Whereas some conventional systems involve the use of expensive arc-spray equipment to apply the metallic zinc used as the sacrificial anode material, the developmental coatings can be applied by use of ordinary paint sprayers. A coating material of the type under development is formulated as a liquid containing blended metallic particles and/or moisture-attracting compounds. The liquid mixture is sprayed onto a concrete structure. Experiments have shown that even though such a coat resides on the exterior surface, it generates a protective galvanic current that flows to the interior reinforcing steel members. By effectively transferring the corrosion process from the steel reinforcement to the exterior coating, the protective current slows or stops corrosion of the embedded steel. Specific formulations have been found to meet depolarization criteria of the National Association of Corrosion Engineers (NACE) for complete protection of steel reinforcing bars ("rebar") embedded in concrete.

  3. Quantitative corrosion monitoring and detection using ultrasonic Lamb waves

    NASA Astrophysics Data System (ADS)

    Gordon, Grant A.; Braunling, Russ

    2005-05-01

    Corrosion is a major problem for airframe operators. For the aircraft industry in general, the direct costs of corrosion are estimated at $2.2 billion. As part of their strategy to control corrosion, airframe operators constantly seek to improve their ability to anticipate, manage and identify corrosion activity. Motivated by the need for an on-line real-time corrosion-monitoring tool for industry and aircraft a prototype system and analysis approach is presented. The tool employs ultrasonic Lamb waves along with a dispersion compensated synthetic aperture focusing technique (SAFT) to detect emerging pitting damage. In order to develop an automated detection approach the noise sources of the SAFT processed defect maps were examined and modeled. The random noise was found to be neither stationary nor normally distributed. Locally varying Weibull distribution parameters are used to characterize the image noise. An algorithm is developed to quantify the uncertainty in the corrosion detection and to allow assignment of a constant false alarm probability to any region of the monitored area.

  4. Study of Caustic Corrosion of Carbon Steel Waste Tanks

    SciTech Connect

    Jenkins, C.F.

    1999-02-24

    Solution chemistry of wastes from US atomic weapons production is controlled to inhibit corrosion of carbon steel tanks used in containment and storage. The pH, nitrate ion and nitrite ion concentrations of fresh solutions are maintained within specified limits for this purpose. In the start up process for a new waste evaporator (RHL WE), non-radioactive solutions of similar chemistry will be circulated through carbon steel piping between a steel tank and the evaporator. The evaporator is fabricated from a corrosion resistant nickel base alloy. The equipment will be exposed continuously to the hot corrosive caustic solutions. Published corrosion rates for steel in pure caustic at the elevated temperatures indicate losses >1.3 mm/y. Because the total test period for start up is relatively short, penetration will not occur. However, concern exists because the rust particles will probably circulate and precipitate throughout the system.A laboratory study was performed in order to determine corrosion to be expected for the specific waste solutions being used in start up testing of the new equipment. In summary, the test results indicate that the corrosion rates for steel are acceptable for the short term simulant tests for the new evaporator. The amount of particulate is probably not a concern, through filtration is recommended as an option. the hydrogen formation is also not a concern because it is in a steam environment, and is continuously swept from the storage vessel.

  5. Electrochemical Investigation of Corrosion in the Space Shuttle Launch Environment

    NASA Technical Reports Server (NTRS)

    Calle, L. M.

    2004-01-01

    Corrosion studies began at NASA/Kennedy Space Center in 1966 during the Gemini/Apollo Programs with the evaluation of long-term protective coatings for the atmospheric protection of carbon steel. An outdoor exposure facility on the beach near the launch pad was established for this purpose at that time. The site has provided over 35 years of technical information on the evaluation of the long-term corrosion performance of many materials and coatings as well as on maintenance procedures. Results from these evaluations have helped NASA find new materials and processes that increase the safety and reliability of our flight hardware, launch structures, and ground support equipment. The launch environment at the Kennedy Space Center (KSC) is extremely corrosive due to the combination of ocean salt spray, heat, humidity, and sunlight. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocket boosters. It has been estimated that 70 tons of hydrochloric acid (HC1) are produced during a launch. The Corrosion Laboratory at NASA/KSC was established in 1985 to conduct electrochemical studies of corrosion on materials and coatings under conditions similar to those encountered at the launch pads. I will present highlights of some of these investigations.

  6. The effects of NOM and coagulation on copper corrosion

    SciTech Connect

    Rehring, J.P.; Edwards, M.

    1994-12-31

    Copper corrosion was examined in solutions containing natural organic matter (NOM) and in situations where NOM was removed by enhanced coagulation with alum or ferric chloride. Electrochemical methods were used to evaluate the long-term effects of each water quality on copper corrosion. In experiments exploring the role of NOM in copper corrosion, corrosion rates increased with NOM concentration at pH 6, whereas at pH 7.5 and 9 the NOM had less significant effects. Waters treated by enhanced alum coagulation had higher corrosion rates than untreated waters, but enhanced ferric chloride coagulation had the opposite effect. This difference was attributed to the relative effects of added sulfate via alum coagulation versus added chloride via ferric chloride coagulation. Compliance with the EPA Lead and Copper Rule and disinfection byproduct regulations may require that utilities address both regulations simultaneously. That is, water treatment processes, NOM concentration, and copper corrosion behavior are clearly interdependent and should be considered when contemplating changes to meet DBP regulations.

  7. A comparative study of atmospheric corrosion in the Caribbean area

    SciTech Connect

    Maldonado, L.; Castro, P.; Echeverria, M.

    1995-10-01

    Atmospheric corrosion is a phenomenon of such a magnitude that has been cause of study in several countries for decades. Nevertheless, in Mexico, it became of recent interest due to new economic factors that have involved the Peninsula of Yucatan too. The Yucatan Peninsula is limited to the North and West by the Gulf of Mexico and to the East by the Caribbean Sea. This is a non industrialized region so that in the past very little importance was given to the atmospheric corrosion damage or to the quantification of the high corrosion rates, empirically observed. However, in recent times increased tourism, industrial growth and petroleum extraction have exhibited the need for a better understanding of the atmospheric corrosion processes, as well as a realistic correlation to parameters such as time-of-wetness, levels of pollution by airborne salinity, atmospheric S0{sub 2} and corrosivity categories for the metals. To evaluate these parameters, five tests sites were selected following ISO recommendations. Three sites are marines atmospheres, one urban and one rural. Corrosion rates for commercial laminated Cu and carbon steel, as well as deposition rates of pollutants, were determined after one year exposure in the test sites. Applying the standard practice ISO 9223 a categorization of the corrosivity and of the level of pollutants was carried out. The marine environments were classified as of atmospheric corrosivity C{sub 5}, while the urban and the rural could be classified as C{sub 3}, respectively. The pollution values showed that the exposure sites were essentially contaminated with chloride with classification S{sub 1} for the rural site and S{sub 3} for the marine atmosphere.

  8. High-Performance Corrosion-Resistant Iron-Based Amorphous Metals: The Effects of Composition, Structure and Environment on Corrosion Resistance

    SciTech Connect

    Farmer, J; Choi, J S; Haslam, J; Lian, T; Day, S; Yang, N; Blue, C; Peters, W; Bayles, R; Lewandowski, J; Perepezko, J; Hildal, K; Lavernia, E; Ajdelsztajn, A; Grave, O; Aprigliano, L; Kaufman, L; Boudreau, J; Branagan, D J; Beardsley, B

    2006-04-11

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative thermal phase stability, microstructure, mechanical properties, damage tolerance, and corrosion resistance. Some alloy additions are known to promote glass formation and to lower the critical cooling rate [F. Guo, S. J. Poon, Applied Physics Letters, 83 (13) 2575-2577, 2003]. Other elements are known to enhance the corrosion resistance of conventional stainless steels and nickel-based alloys [A. I. Asphahani, Materials Performance, Vol. 19, No. 12, pp. 33-43, 1980] and have been found to provide similar benefits to iron-based amorphous metals. Many of these materials can be cast as relatively thick ingots, or applied as coatings with advanced thermal spray technology. A wide variety of thermal spray processes have been developed by industry, and can be used to apply these new materials as coatings. Any of these can be used for the deposition of the formulations discussed here, with varying degrees of residual porosity and crystalline structure. Thick protective coatings have now been made that are fully dense and completely amorphous in the as-sprayed condition. An overview of the High-Performance Corrosion Resistant Materials (HPCRM) Project will be given, with particular emphasis on the corrosion resistance of several different types of iron-based amorphous metals in various environments of interest. The salt fog test has been used to compare the performance of various wrought alloys, melt-spun ribbons, arc-melted drop-cast ingots, and thermal-spray coatings for their susceptibility to corrosion in marine environments. Electrochemical tests have also been performed in seawater. Spontaneous breakdown of the passive film and localized corrosion require that the open-circuit corrosion potential exceed the critical potential. The resistance to localized corrosion is seawater has been

  9. Constitution of green rust and its significance to the corrosion of steel in Portland cement

    SciTech Connect

    Sagoe-Crentsil, K.K. . Div. of Building Construction and Engineering); Glasser, F.P. . Dept. of Chemistry)

    1993-06-01

    Studies of the corrosion of pure iron showed green rust, approximately Fe[sub 4][sup 2+]Fe[sub 2][sup 3+] (OH)[sub 12](Cl,OH)[sub 2], was a stable corrosion product at high pH and low E[sub h] in the presence of chloride. The structure, constitution, preparation, and characterization of green rust was reviewed. A diagram relevant to the corrosion of iron in cement, constructed for pH 12, showed stability fields of green rust, [alpha],[delta] FeO(OH), and [beta]FeO(OH,Cl). Overall implications of chloride to the corrosion process were investigated.

  10. Cathodic protection against crevice corrosion of high-alloy steel in seawater

    SciTech Connect

    Baptista, W.; Pimenta, G.

    1995-10-01

    Localized corrosion of high-alloy steel in seawater, mainly under crevices, limits the alloys` use in such environments. An in-situ test program was conducted to study this corrosive process and possible protective measures. Attention focused on the resistance of several types of high-alloy steels under corrosive conditions and on the response of type 316 stainless steel to cathodic protection (CP) by carbon steel and zinc anodes. It was found that CP could effectively mitigate crevice corrosion in these subsea conditions.

  11. Characterization of the corrosion resistance of biologically active solutions: The effects of anodizing and welding

    NASA Technical Reports Server (NTRS)

    Walsh, Daniel W.

    1991-01-01

    An understanding of fabrication processes, metallurgy, electrochemistry, and microbiology is crucial to the resolution of microbiologically influenced corrosion (MIC) problems. The object of this effort was to use AC impedance spectroscopy to characterize the corrosion resistance of Type II anodized aluminum alloy 2219-T87 in sterile and biologically active media and to examine the corrosion resistance of 316L, alloy 2219-T87, and titanium alloy 6-4 in the welded and unwelded conditions. The latter materials were immersed in sterile and biologically active media and corrosion currents were measured using the polarization resistance (DC) technique.

  12. Inspection of corrosion in carbody and under frame for rolling stocks using pulsed eddy current testing

    NASA Astrophysics Data System (ADS)

    Lee, C. W.; Chung, J. D.

    2011-04-01

    Under frame side sill and carbody of rolling stock structures are designed for preventing corrosion in order to meet mechanical requirements. However during long operation time more than 30 years, there are corrosion in the under frame side sill caused by environmental effect, vibration and etc. So, detection and evaluation of the corrosion in the under frame nondestructive is one of important and extending their life time. So, in this study, we have investigated performance of pulsed eddy current testing method by measuring thickness variation of fabricate of carbody and under frame for rolling stocks. And then, the process of evaluating remaining life according to testing of corrosion amount is introduced.

  13. Application of Terahertz Radiation to the Detection of Corrosion under the Shuttle's Thermal Protection System

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Anastasi, Robert F.; Smith, Stephen W.; Seebo, Jeffrey P.; Walker, James L.; Lomness, Janice K.; Hintze, Paul E.; Kammerer, Catherine C.; Winfree, William P.; Russell, Richard W.

    2007-01-01

    There is currently no method for detecting corrosion under Shuttle tiles except for the expensive process of tile removal and replacement; hence NASA is investigating new NDE methods for detecting hidden corrosion. Time domain terahertz radiation has been applied to corrosion detection under tiles in samples ranging from small lab samples to a Shuttle with positive results. Terahertz imaging methods have been able to detect corrosion at thicknesses of 5 mils or greater under 1" thick Shuttle tiles and 7-12 mils or greater under 2" thick Shuttle tiles.

  14. Millimeter Wave Nondestructive Evaluation of Corrosion Under Paint in Steel Structures

    SciTech Connect

    Kharkovsky, S.; Zoughi, R.

    2006-03-06

    Millimeter wave nondestructive evaluation techniques have shown great potential for detection of corrosion under paint in steel structures. They may also provide for detection of other anomalies associated with the corrosion process such as precursor pitting. This paper presents the results of an extensive investigation spanning a frequency range of 30-100 GHz and using magnitude- and phase-sensitive reflectometers. Using 2D automated scanning mechanisms, raster images of two corrosion patches are produced showing the spatial resolution capabilities of these systems as well as their potential for evaluating localized corrosion severity.

  15. Corrosion protection of aluminum by silane-based surface treatment

    NASA Astrophysics Data System (ADS)

    Song, Jun

    treatment layers and their stability in the under-film corrosion environment. Salt spray test results showed that two-step BTSE/gamma-APS could provide the same or better corrosion protection than that offered by a standard chromate treatment. Polyester or polyurethane powder-painted Al panels, pretreated with this treatment, also displayed excellent corrosion performances in the salt spray test and filiform corrosion test. Thus, the advantage of this treatment is that is combines a temporary rust prevention and a permanent prepaint treatment into one simple approach. Electrochemical impedance spectroscopy was used to study the various pre-paint treatments under the polyester paint. It provides more detailed mechanistic information about corrosion processes than salt spray test and filiform corrosion test. However, combination of corrosion tests that involve different corrosion mechanisms may still be necessary to have a better understanding of corrosion behavior of a new treatment.

  16. Bonding-Compatible Corrosion Inhibitor for Rinsing Metals

    NASA Technical Reports Server (NTRS)

    Saunders, C. R.; Wurth, L. A.; Radar, A.

    2005-01-01

    A corrosion-inhibiting mixture of compounds has been developed for addition to the water used to rinse metal parts that have been cleaned with aqueous solutions in preparation for adhesive bonding of the metals to rubber and rubber-like materials. Prior to the development of this corrosion inhibitor, the parts (made, variously, of D6AC steel and 7075-T73 aluminum) were rinsed by deionized water, which caused corrosion in some places on the steel parts especially in such occluded places as sealing surfaces and threaded blind holes. An integral part of the particular cleaning process is the deposition of a thin layer of silicates and silane primers that increase the strength of the adhesive bond. The corrosion inhibitor is formulated, not only to inhibit corrosion of both D6AC steel and 7075- T73 aluminum, but also to either increase or at least not reduce the strength of the adhesive bond to be formed subsequently. The corrosion inhibitor is a mixture of sodium silicate and sodium tetraborate. The sodium silicate functions as both a corrosion inhibitor and a bond-strength promoter in association with the silane primers. The sodium tetraborate buffers the rinse solution at the optimum pH and functions as a secondary corrosion inhibitor for the steel. For a given application, the concentrations of sodium silicate and sodium tetraborate must be chosen in a compromise among the needs to inhibit corrosion of steel, inhibit corrosion of aluminum, and minimize cosmetic staining of both steel and aluminum. Concentrations of sodium silicate in excess of 150 parts of silicon per million parts of solution (ppm Si) have been determined to enhance inhibition of corrosion; unfortunately, because of the alkalinity of sodium silicate, even a small concentration can raise the pH of the rinse solution to such a level that aluminum becomes corroded despite the inhibiting effect. The pH of a solution that contains a high concentration of sodium silicate can be decreased by adding

  17. Literature review of metal corrosion sensitivity in high temperature, high impurity hot cell atmospheres

    SciTech Connect

    Eberle, C.S.

    1997-09-01

    The pyrochemical conditions of spent nuclear fuel for the purpose of final disposal is being demonstrated at Argonne National Laboratory (ANL). One aspect of this program is to develop a lithium preprocessing stage for the Fuel Conditioning Facility (FCF). One of the design considerations under investigation in this program is the system`s corrosion response in the presence of irradiated commercial fuel as well as atmospheric impurities. Static corrosion coupon tests have been completed which demonstrate the potential corrosivity of the salt matrix in a worse case environment as well as provide a boundary for allowable impurities in the system during operation. The literature concerning corrosion of either fused salts or molten metals consistently emphasizes three similar features which are common to both systems: (1) the overall corrosion rate is strongly dependent on temperature, impurity concentration and flow velocity; (2) many different mechanisms can be involved in a specific corrosion process; and (3) corrosion rates will significantly increase as all three of these independent variables are increased. The qualitative and quantitative understanding of these corrosion results is important for this spent fuel program since all of these variables will increase as the process scale increases. The purpose of this work was to determine if any data existed which could provide a quantitative expectation for corrosion rates of refractory metals in a lithium chloride salt bath.

  18. The effect of conditioning agents on the corrosive properties of molten urea

    SciTech Connect

    Nichols, D E; Nguyen, D T; Norton, M M; Parker, B R; Daniels, L E

    1991-01-01

    From the process case histories of the failure of several heat exchanger tube bundles, it was revealed that molten urea containing lignosulfonate as a granulation conditioning-hardening agent (Urea LS[trademark]) is corrosive to Types 304 and 316 stainless steel. The results of field and laboratory immersion corrosion tests indicated that the corrosivity of molten urea is strongly dependent on the process temperature rather than the conditioner composition. At temperatures below 295F, molten Urea LS[trademark] is not aggressive to these stainless steels. However, at temperatures above 300F, the corrosion of these stainless steels is extremely severe. The corrosion rate of Types 304, 304L, 316, and 316L is as high as hundreds of mils per year. The corrosion mechanism tends to be more general than localized. The results of the laboratory corrosion test also revealed that among alloying elements, copper is detrimental to corrosion resistance of stainless steel exposed to molten Urea LS[trademark], chromium is the most beneficial, and nickel has only a minor effect. Thus, copper-free and chromium stainless steels have superior corrosion resistance to the molten Urea LS[trademark] at a wide range of temperatures up to 345F.

  19. Corrosion-resistant sulfur concretes

    NASA Astrophysics Data System (ADS)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  20. Mullite coatings for corrosion protection of silicon carbide

    SciTech Connect

    Mulpuri, R.; Sarin, V.K.

    1995-08-01

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can satisfy the stringent requirements imposed by such applications. Chemical Vapor Deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and a good coefficient of thermal expansion match with SiC are being investigated as a potential candidate. Since mullite has never been successfully grown via CVD, the thermodynamics and kinetics of its formation were initially established and used as a guideline in determining the initial process conditions. Process optimization was carried out using an iterative process of theoretical analysis and experimental work coupled with characterization and testing. The results of theoretical analysis and the CVD formation characteristics of mullite are presented.

  1. Corrosion of breached UF{sub 6} storage cylinders

    SciTech Connect

    Barber, E.J.; Taylor, M.S.; DeVan, J.H.

    1993-02-01

    This paper describes the corrosion processes that occurred following the mechanical failure of two steel 14-ton storage cylinders containing depleted UF{sub 6}. The failures both were traced to small mechanical tears that occurred during stacking of the cylinders. Although subsequent corrosion processes greatly extended the openings in the wall. the reaction products formed were quite protective and prevented any significant environmental insult or loss of uranium. The relative sizes of the two holes correlated with the relative exposure times that had elapsed from the time of stacking. From the sizes and geometries of the two holes, together with analyses of the reaction products, it was possible to determine the chemical reactions that controlled the corrosion process and to develop a scenario for predicting the rate of hydrolysis of UF{sub 6}, the loss rate of HF, and chemical attack of a breached UF{sub 6} storage cylinder.

  2. Corrosion of breached UF[sub 6] storage cylinders

    SciTech Connect

    Barber, E.J.; Taylor, M.S.; DeVan, J.H.

    1993-01-01

    This paper describes the corrosion processes that occurred following the mechanical failure of two steel 14-ton storage cylinders containing depleted UF[sub 6]. The failures both were traced to small mechanical tears that occurred during stacking of the cylinders. Although subsequent corrosion processes greatly extended the openings in the wall. the reaction products formed were quite protective and prevented any significant environmental insult or loss of uranium. The relative sizes of the two holes correlated with the relative exposure times that had elapsed from the time of stacking. From the sizes and geometries of the two holes, together with analyses of the reaction products, it was possible to determine the chemical reactions that controlled the corrosion process and to develop a scenario for predicting the rate of hydrolysis of UF[sub 6], the loss rate of HF, and chemical attack of a breached UF[sub 6] storage cylinder.

  3. Corrosion and corrosion fatigue of airframe aluminum alloys

    NASA Technical Reports Server (NTRS)

    Chen, G. S.; Gao, M.; Harlow, D. G.; Wei, R. P.

    1994-01-01

    Localized corrosion and corrosion fatigue crack nucleation and growth are recognized as degradation mechanisms that effect the durability and integrity of commercial transport aircraft. Mechanically based understanding is needed to aid the development of effective methodologies for assessing durability and integrity of airframe components. As a part of the methodology development, experiments on pitting corrosion, and on corrosion fatigue crack nucleation and early growth from these pits were conducted. Pitting was found to be associated with constituent particles in the alloys and pit growth often involved coalescence of individual particle-nucleated pits, both laterally and in depth. Fatigue cracks typically nucleated from one of the larger pits that formed by a cluster of particles. The size of pit at which fatigue crack nucleates is a function of stress level and fatigue loading frequency. The experimental results are summarized, and their implications on service performance and life prediction are discussed.

  4. Corrosion manual for internal corrosion of water distribution systems

    SciTech Connect

    Singley, J.E.; Beaudet, B.A.; Markey, P.H.

    1984-04-01

    Corrosion of distribution piping and of home plumbing and fixtures has been estimated to cost the public water supply industry more than $700 million per year. Two toxic metals that occur in tap water, almost entirely because of corrosion, are lead and cadmium. Three other metals, usually present because of corrosion, cause staining of fixtures, or metallic taste, or both. These are copper (blue stains and metallic taste), iron (red-brown stains and metallic taste), and zinc (metallic taste). Since the Safe Drinking Water Act (P.L. 93-523) makes the supplying utility responsible for the water quality at the customer's tap, it is necessary to prevent these metals from getting into the water on the way to the tap. This manual was written to give the operators of potable water treatment plants and distribution systems an understanding of the causes and control of corrosion.

  5. Alloying of metals for corrosion resistance

    SciTech Connect

    McCafferty, E.; Hubler, G.K.; Natishan, P.M.

    1989-09-29

    The corrosion resistance of bulk metals is improved by implanting a corrosion-resistant species into the surface of the bulk metal in a layer beginning at the surface and extending to a depth of at least about 50 angstroms. An amount of corrosion-resistant species is deposited so that the oxide layer that forms on the corrosion-resistant species implanted bulk metal is composed of at least about three percent of the oxide of the corrosion-resistant species.

  6. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, T.D.

    1996-07-23

    Ceramic materials are disclosed which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200--550 C or organic salt (including SO{sub 2} and SO{sub 2}Cl{sub 2}) at temperatures of 25--200 C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components. 1 fig.

  7. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1996-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  8. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1995-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  9. Review on stress corrosion and corrosion fatigue failure of centrifugal compressor impeller

    NASA Astrophysics Data System (ADS)

    Sun, Jiao; Chen, Songying; Qu, Yanpeng; Li, Jianfeng

    2015-03-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  10. Statistical design of a uranium corrosion experiment

    SciTech Connect

    Wendelberger, Joanne R; Moore, Leslie M

    2009-01-01

    This work supports an experiment being conducted by Roland Schulze and Mary Ann Hill to study hydride formation, one of the most important forms of corrosion observed in uranium and uranium alloys. The study goals and objectives are described in Schulze and Hill (2008), and the work described here focuses on development of a statistical experiment plan being used for the study. The results of this study will contribute to the development of a uranium hydriding model for use in lifetime prediction models. A parametric study of the effect of hydrogen pressure, gap size and abrasion on hydride initiation and growth is being planned where results can be analyzed statistically to determine individual effects as well as multi-variable interactions. Input to ESC from this experiment will include expected hydride nucleation, size, distribution, and volume on various uranium surface situations (geometry) as a function of age. This study will also address the effect of hydrogen threshold pressure on corrosion nucleation and the effect of oxide abrasion/breach on hydriding processes. Statistical experiment plans provide for efficient collection of data that aids in understanding the impact of specific experiment factors on initiation and growth of corrosion. The experiment planning methods used here also allow for robust data collection accommodating other sources of variation such as the density of inclusions, assumed to vary linearly along the cast rods from which samples are obtained.

  11. [The management of corrosive oesophagitis (author's transl)].

    PubMed

    Lallemant, Y; Gehanno, P; Flieder, J; Barrier, M; Martin, M

    1978-06-01

    Regardless of the treatment used against corrosive oesophagitis, the laryngologist must play a role from the beginning and throughout the course. The fibroblasts and collagen fibres which results are the natural agents of healing but, at the same time, are responsible for virtually inexorable stenosis if the corrosion has passed through to the muscular layers. Infection is constant and contributes to stenosis. The effectiveness of antibiotics is certain. They must be used from the beginning and continued for as long as necessary. As far as fibroiss is concerned, dilatations remain the basic treatment, their application requiring great experience and much patience and tenacity. Replacement surgery is attractive. It comes up against the stenosing perioesophageal inflammatory process which tends to die down in time but remains active for a long period. The nENT specialist must therefore pay careful attention from the very end of the postoperative period onwards. The gravity of oesophageal burns justifies intensification of preventive measures. Since it impossible to complete eliminate corrosive oesophagitis, efforts must be directed towards the discovery of substances capable of inhibiting collagen synthesis. Corticosteroids used in the treatment of shock do not prevent stenosis. In the laboratory, B.A.P.N. has shown its effectiveness in the rat. Also in the rat, particularly difficult experiments are in progress using penicillinamine. Although such methods have as yet to be extended to human clinical use, there are nevertheless grounds for hope. PMID:742792

  12. Combat incinerator offgas corrosion; Part 1

    SciTech Connect

    Brady, J.D.

    1994-01-01

    Thermal oxidation in sophisticated incineration systems has become the technically preferred method for permanent disposal of chemical wastes, medical wastes, and hazardous wastes. The waste streams processed in these incineration systems contain sulfur, chlorine, fluorine, bromine, iodine, nitrogen, and phosphorus compounds. After combustion, they all form corrosive acidic liquids when absorbed in water. The resulting solutions can cause severe corrosion problems with most common metals. Upon initial gas contact with the scrubbing liquid, the pH can precipitously drop to less than zero, simultaneously with alternate high and low temperature swings. The combination of thermal shock and severely corrosive conditions can destroy improperly selected materials in minutes or hours to result in catastrophic system failures. After the gas stream has been quenched, materials selection, while still critical, becomes somewhat simpler. In general, nonmetallic materials are used where mechanical stress levels allow their use. However, when mechanical strength becomes a major concern, the high nickel alloys must be used. This article discusses the operating conditions which scrubbing systems are subjected to in incinerator applications, and materials selection for various component parts of the scrubbing system. The use of refractories, high nickel alloys, thermoplastics, fiber reinforced plastics, and rubber coatings will be reviewed.

  13. Stress Corrosion Cracking of Carbon Steel Weldments

    SciTech Connect

    POH-SANG, LAM

    2005-01-13

    An experiment was conducted to investigate the role of weld residual stress on stress corrosion cracking in welded carbon steel plates prototypic to those used for nuclear waste storage tanks. Carbon steel specimen plates were butt-joined with Gas Metal Arc Welding technique. Initial cracks (seed cracks) were machined across the weld and in the heat affected zone. These specimen plates were then submerged in a simulated high level radioactive waste chemistry environment. Stress corrosion cracking occurred in the as-welded plate but not in the stress-relieved duplicate. A detailed finite element analysis to simulate exactly the welding process was carried out, and the resulting temperature history was used to calculate the residual stress distribution in the plate for characterizing the observed stress corrosion cracking. It was shown that the cracking can be predicted for the through-thickness cracks perpendicular to the weld by comparing the experimental KISCC to the calculated stress intensity factors due to the welding residual stress. The predicted crack lengths agree reasonably well with the test data. The final crack lengths appear to be dependent on the details of welding and the sequence of machining the seed cracks, consistent with the prediction.

  14. Method for applying corrosion resistant metallic coating of zirconium nitride

    SciTech Connect

    Bryan, W.J.; Corsetti, L.V.

    1993-07-13

    A process is described for enhancing the wear and corrosion resistance of a cladding tube for a nuclear fuel rod, comprising reactively depositing zirconium nitride on the surface of said cladding tube by a cathodic arc plasma deposition process to form a thin wear resistant coating.

  15. Laser surface melting of aluminium alloy 6013 for improving stress corrosion and corrosion fatigue resistance

    NASA Astrophysics Data System (ADS)

    Xu, Wen-Long

    that of the excimer laser formed surface film. When comparing the stress corrosion cracking resistance of the excimer laser and YAG laser treated specimens in terms of elongation reduction, the latter was found to be superior. This is considered to be caused by the tortuous fracture path which occurred in the YAG laser re-melted layer. This has the advantage of reducing the effective stress intensity at the crack front, and thus delays the fracture process. However, it must be recognised that a drop in tensile strength occurred after YAG laser treatment. This drop is primarily considered to be the result of the formation of a relatively thick and soft re-melted and heat affected layer. Considering the pitting corrosion fatigue, though, similar to the case of excimer laser melting, the initiation of fatigue cracks can be effectively retarded after YAG laser treatment, the mode of crack propagation was different for the two situations. Crack propagation within the YAG laser re-melt layer primarily followed interdendritic boundaries, and resulted in a rough fracture surface. A tortuous interdendritic crack path may result in a relatively low fatigue growth rate. By contrast, a relatively flat fracture surface was produced when excimer laser treatment was used. Finally, it was found that the electrochemical noise method is a promising means for in-situ monitoring of pitting corrosion fatigue damage of the laser-melted layer both for excimer and Nd:YAG laser treatments. The results showed that fatigue crack initiation and propagation phenomena could be correlated to the patterns of electrochemical potential and current noise.

  16. Environmental and alloying effects on corrosion of metals and alloys

    NASA Astrophysics Data System (ADS)

    Liang, Dong

    2009-12-01

    In the first part of this project, corrosion studies were carried out on 304L stainless steel samples welded with Cr-free consumables, which were developed to minimize the concentration of chromate species in the weld fume. The corrosion properties of Ni-Cu and Ni-Cu-Pd Gas Tungsten Arc (GTA) welds and Shielded Metal Arc (SMA) welds are comparable to those of welds fabricated with SS308L consumable, which is the standard consumable for welding 304L. Although the breakdown potentials of the new welds from both welding processes are lower than that of the SS308L weld, the repassivation potential of these new welds is much higher. Generally, the repassivation potential is a more conservative measure of susceptibility to localized corrosion. Our studies showed that the Ni-Cu and Ni-Cu-Pd welds are more resistant to crevice corrosion than SS308L welds, which is related to the high repassivation potential. Also, addition of Pd improved the corrosion resistance of the new welds, which is consistent with previous studies from button samples and bead-on-plate samples. Other corrosion studies such as creviced and uncreviced long time immersion, atmospheric exposure, and slow strain rate testing suggest that Ni-Cu-Pd welds can be a qualified substitute for SS308 weld. In the second part of this project, efforts are put on the connection between lab and field exposure tests because sometimes the correspondence between lab atmospheric corrosion tests (ASTM B117) and field exposures is poor as a result of differences in the critical conditions controlling chemical and electrochemical reactions on surfaces. Recent studies in atmospheric chemistry revealed the formation of extremely reactive species from interactions between UV light, chloride aerosols above oceans and oxidizing agents such as ozone or peroxide. Atmospheric corrosion of metals can be affected by these species which might be transported long distances in the atmosphere to locations far from oceans. However, these

  17. Calcium carbonate corrosivity in an Alaskan inland sea

    NASA Astrophysics Data System (ADS)

    Evans, W.; Mathis, J. T.; Cross, J. N.

    2013-12-01

    Ocean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO2, and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO3) saturation states (Ω) to levels that are corrosive (i.e. Ω ≤ 1) to shell-forming marine organisms. However, other processes can drive CaCO3 corrosivity; specifically, the addition of tidewater glacier melt. To highlight this process, we present carbonate system data collected in May (spring) and September (autumn) starting 2009 through 2012 from Prince William Sound (PWS), a semi-enclosed inland sea located on the south-central coast of Alaska that is ringed with fjords containing tidewater glaciers. Initial sampling in PWS covered limited stations in the western sound, and Ω levels corrosive to aragonite, a form of CaCO3, were observed in association with glacial melt during autumn. Beginning in September 2011, expanded sampling spanned the western and central sound, and included two fjords proximal to tidewater glaciers: Icy Bay and Columbia Bay. The observed conditions in these fjords affected CaCO3 corrosivity in the upper water column (< 50 m) in PWS in two ways: (1) as spring-time formation sites of mode water with near-corrosive Ω levels seen below the mixed layer depth across the sound, and (2) as point sources for surface plumes of glacial melt with corrosive Ω levels (Ω for aragonite and calcite down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures (pCO2) well below atmospheric levels. The cumulative effect of glacial melt is likely responsible for the seasonal widespread reduction of Ω in PWS; however, glacial melt-driven CaCO3 corrosivity is poorly reflected by pCO2 or pHT, indicating that any one of those carbonate parameters alone would inadequately track corrosive conditions in PWS. The unique conditions of the carbonate system in the surface glacial melt plumes enhances atmospheric CO2 uptake, which, if

  18. A Comprehensive Investigation of Copper Pitting Corrosion in a Drinking Water Distribution System

    EPA Science Inventory

    Copper pipe pitting is a complicated corrosion process for which exact causes and solutions are uncertain. This paper presents the findings of a comprehensive investigation of a cold water copper pitting corrosion problem in a drinking water distribution system, including a refi...

  19. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  20. Argentinean map of atmospheric corrosivities

    SciTech Connect

    Rosales, B.M.; Ayllon, E.S.; Leiro, M.C.; Fernandez, A.; Moriena, G.; Varela, F.; Codaro, E.N.; Vilche, J.R.

    1995-10-01

    In the present paper the results obtained by the Argentinean research groups integrated in the MICAT (Iberoamerican Map of Atmospheric Corrosion) Project are given. Outdoor exposure in 6 test situations of different environmental conditions were performed by quadruplicate, on plain carbon steel and pure zinc, copper and aluminium, during yearly periods from 1 to 4 years. Three samples were used for the weight loss determinations while the fourth one was used to characterize the corrosion products formed through electrochemical d.c. and a.c. techniques and SEM-EDAX surface analysis. Good correlations were observed among the corrosion rates, the environmental conditions, both electrochemical techniques and the morphology of the rusts in plant and in polished cross sections. The techniques applied allowed to evidence the different protectiveness of the rusts formed on the metals, according to the solubility, morphology, hygroscopic power and pollutants content of the corrosion products` components.

  1. Assessing the effect of cement-steel interface on well casing corrosion in aqueous CO2 environments

    SciTech Connect

    Han, Jiabin; Carey, James W; Zhang, Jinsuo

    2010-01-01

    CO{sub 2} leakage is a critical safety concern for geologic storage. In wellbore environments, important leakage paths include the rock-cement and cement-casing interfaces. If the cement-casing interface is filled with escaping CO{sub 2}, the well casing directly contacts the CO{sub 2}. This can cause severe corrosion in the presence of water. This paper studies the effect of steel-cement interface gaps, ranging from 1 mm to 0 um, on casing corrosion. Corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance, open circuit potential and electrochemical impedance spectroscopy. The experimental results showed that the corrosion of steel is not significant where the gap between steel and cement is small ({le} 100 {micro}m). Corrosion rates are controlled by the diffusion of corrosive species (H{sub 2}CO{sub 3} and H{sup +}) along the interface. In contrast, steel corrosion is severe in a broad gap where the corrosion process is limited only by the reaction kinetics of steel and corrosive species. The threshold leading to severe corrosion in terms of the cement-steel interface size (100 {micro}m) was determined. Our research clarifies a corrosion scenario at the cement-steel interface. Casing steel corrosion is initiated when attacked by corrosive species at the cement-steel interface. For relatively tight interfaces, this results in a slow thinning of the casing and expansion of the interface width. If the gap increases beyond the critical threshold size, the corrosion rate increases significantly, and a potentially damaging cycle of corrosion and interface expansion is developed.

  2. Effects of laser heat treatment on the fracture morphologies of X80 pipeline steel welded joints by stress corrosion

    NASA Astrophysics Data System (ADS)

    Kong, De-jun; Ye, Cun-dong

    2014-09-01

    The surfaces of X80 pipeline steel welded joints were processed with a CO2 laser, and the effects of laser heat treatment (LHT) on H2S stress corrosion in the National Association of Corrosion Engineers (NACE) solution were analyzed by a slow strain rate test. The fracture morphologies and chemical components of corrosive products before and after LHT were analyzed by scanning electron microscopy and energy-dispersive spectroscopy, respectively, and the mechanism of LHT on stress corrosion cracking was discussed. Results showed that the fracture for welded joints was brittle in its original state, while it was transformed to a ductile fracture after LHT. The tendencies of hydrogen-induced corrosion were reduced, and the stress corrosion sensitivity index decreased from 35.2% to 25.3%, indicating that the stress corrosion resistance of X80 pipeline steel welded joints has been improved by LHT.

  3. Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique.

    PubMed

    Zaki, Ahmad; Chai, Hwa Kian; Aggelis, Dimitrios G; Alver, Ninel

    2015-08-05

    Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods.

  4. Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

    PubMed Central

    Zaki, Ahmad; Chai, Hwa Kian; Aggelis, Dimitrios G.; Alver, Ninel

    2015-01-01

    Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods. PMID:26251904

  5. CORROSION STUDY OF AMORPHOUS METAL RIBBONS

    SciTech Connect

    Lian, T; Day, S D; Farmer, J C

    2006-07-31

    Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The potential advantages of amorphous metals have been recognized for some time [Latanison 1985]. Iron-based corrosion-resistant, amorphous-metal coatings under development may prove important for maritime applications [Farmer et al. 2005]. Such materials could also be used to coat the entire outer surface of containers for the transportation and long-term storage of spent nuclear fuel, or to protect welds and heat affected zones, thereby preventing exposure to environments that might cause stress corrosion cracking [Farmer et al. 1991, 2000a, 2000b]. In the future, it may be possible to substitute such high-performance iron-based materials for more-expensive nickel-based alloys, thereby enabling cost savings in a wide variety of industrial applications. It should be noted that thermal-spray ceramic coatings have also been investigated for such applications [Haslam et al. 2005]. This report focuses on the corrosion resistance of iron-based melt-spun amorphous metal ribbons. Melt-Spun ribbon is made by rapid solidification--a stream of molten metal is dropped onto a spinning copper wheel, a process that enables the manufacture of amorphous metals which are unable to be manufactured by conventional cold or hot rolling techniques. The study of melt-spun ribbon allows quick evaluation of amorphous metals corrosion resistance. The melt-spun ribbons included in this study are DAR40, SAM7, and SAM8, SAM1X series, and SAM2X series. The SAM1X series ribbons have

  6. Testing and prediction of erosion-corrosion for corrosion resistant alloys used in the oil and gas production industry

    NASA Astrophysics Data System (ADS)

    Rincon, Hernan E.

    The corrosion behavior of CRAs has been thoroughly investigated and documented in the public literature by many researchers; however, little work has been done to investigate erosion-corrosion of such alloys. When sand particles are entrained in the flow, the degradation mechanism is different from that observed for sand-free corrosive environment. There is a need in the oil and gas industry to define safe service limits for utilization of such materials. The effects of flow conditions, sand rate, pH and temperature on the erosion-corrosion of CRAs were widely studied. An extensive experimental work was conducted using scratch tests and flow loop tests using several experimental techniques. At high erosivity conditions, a synergistic effect between erosion and corrosion was observed. Under the high sand rate conditions tested, erosivity is severe enough to damage the passive layer protecting the CRA thereby enhancing the corrosion rate. In most cases there is likely a competition between the rates of protective film removal due to mechanical erosion and protective film healing. Synergism occurs for each of the three alloys examined (13Cr and Super13Cr and 22Cr); however, the degree of synergism is quite different for the three alloys and may not be significant for 22Cr for field conditions where erosivities are typically much lower that those occurring in the small bore loop used in this research. Predictions of the corrosion component of erosion-corrosion based on scratch test data compared reasonably well to test results from flow loops for the three CRAs at high erosivity conditions. Second order behavior appears to be an appropriate and useful model for representing the repassivation process of CRAs. A framework for a procedure to predict penetration rates for erosion-corrosion conditions was developed based on the second order model behavior observed for the re-healing process of the passive film of CRAs and on computational fluid dynamics (CFD) simulations

  7. Environmentally Friendly Corrosion Preventative Compounds

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Montgomery, Eliza; Kolody, Mark; Curran, Jerry; Back, Teddy; Balles, Angela

    2012-01-01

    The objective of the Ground Systems Development and Operations Program Environmentally Friendly Corrosion Protective Coatings and Corrosion Preventive Compounds (CPCs) project is to identify, test, and develop qualification criteria for the use of environmentally friendly corrosion protective coatings and CPCs for flight hardware and ground support equipment. This document is the Final Report for Phase I evaluations, which included physical property, corrosion resistance, and NASA spaceport environment compatibility testing and analysis of fifteen CPC types. The CPCs consisted of ten different oily film CPCs and five different wax or grease CPC types. Physical property testing encompassed measuring various properties of the bulk CPCs, while corrosion resistance testing directly measured the ability of each CPC material to protect various metals against corrosion. The NASA spaceport environment compatibility testing included common tests required by NASA-STD-6001, "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion". At the end of Phase I, CPC materials were down-selected for inclusion in the next test phases. This final report includes all data and analysis of results obtained by following the experimental test plan that was developed as part of the project. Highlights of the results are summarized by test criteria type.

  8. Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste

    NASA Astrophysics Data System (ADS)

    Duffó, G. S.; Farina, S. B.; Schulz, F. M.

    2013-07-01

    Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums. The corrosion rate of the steel in contact with cemented ion-exchange resins in the absence of contaminants or in the presence of 2.3 wt.% sulphate content remains low (less than 0.1 μm/year) during the whole period of the study (900 days). The presence of chloride ions increases the corrosion rate of the steel at the beginning of the exposure but, after 1 year, the corrosion rate drops abruptly reaching a value close to 0.1 μm/year. This is probably due to the lack of water to sustain the corrosion process. When applying the results obtained in the present work to estimate the corrosion depth of the steel drums containing the cemented radioactive waste after a period of 300 years, it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums. Cementation of ion-exchange resins does not seem to pose special risks regarding the corrosion of the steel drums that contained them; even in the case the matrix is highly contaminated with chloride ions.

  9. Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V.

    PubMed

    Grotberg, John; Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Shokuhfar, Tolou; Sukotjo, Cortino; Takoudis, Christos; Mathew, Mathew T

    2016-02-01

    The negative impact of in vivo corrosion of metallic biomedical implants remains a complex problem in the medical field. We aimed to determine the effects of electrochemical anodization (60V, 2h) and thermal oxidation (600°C) on the corrosive behavior of Ti-6Al-4V, with serum proteins, at physiological temperature. Anodization produced a mixture of anatase and amorphous TiO2 nanopores and nanotubes, while the annealing process yielded an anatase/rutile mixture of TiO2 nanopores and nanotubes. The surface area was analyzed by the Brunauer-Emmett-Teller method and was estimated to be 3 orders of magnitude higher than that of polished control samples. Corrosion resistance was evaluated on the parameters of open circuit potential, corrosion potential, corrosion current density, passivation current density, polarization resistance and equivalent circuit modeling. Samples both anodized and thermally oxidized exhibited shifts of open circuit potential and corrosion potential in the noble direction, indicating a more stable nanoporous/nanotube layer, as well as lower corrosion current densities and passivation current densities than the smooth control. They also showed increased polarization resistance and diffusion limited charge transfer within the bulk oxide layer. The treatment groups studied can be ordered from greatest corrosion resistance to least as Anodized+Thermally Oxidized > Anodized > Smooth > Thermally Oxidized for the conditions investigated. This study concludes that anodized surface has a potential to prevent long term implant failure due to corrosion in a complex in-vivo environment. PMID:26652422

  10. Sulfate-reducing bacteria inhabiting natural corrosion deposits from marine steel structures.

    PubMed

    Païssé, Sandrine; Ghiglione, Jean-François; Marty, Florence; Abbas, Ben; Gueuné, Hervé; Amaya, José Maria Sanchez; Muyzer, Gerard; Quillet, Laurent

    2013-08-01

    In the present study, investigations were conducted on natural corrosion deposits to better understand the role of sulfate-reducing bacteria (SRB) in the accelerated corrosion process of carbon steel sheet piles in port environments. We describe the abundance and diversity of total and metabolically active SRB within five natural corrosion deposits located within tidal or low water zone and showing either normal or accelerated corrosion. By using molecular techniques, such as quantitative real-time polymerase chain reaction, denaturing gel gradient electrophoresis, and sequence cloning based on 16S rRNA, dsrB genes, and their transcripts, we demonstrated a clear distinction between SRB population structure inhabiting normal or accelerated low-water corrosion deposits. Although SRB were present in both normal and accelerated low-water corrosion deposits, they dominated and were exclusively active in the inner and intermediate layers of accelerated corrosion deposits. We also highlighted that some of these SRB populations are specific to the accelerated low-water corrosion deposit environment in which they probably play a dominant role in the sulfured corrosion product enrichment.

  11. Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V.

    PubMed

    Grotberg, John; Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Shokuhfar, Tolou; Sukotjo, Cortino; Takoudis, Christos; Mathew, Mathew T

    2016-02-01

    The negative impact of in vivo corrosion of metallic biomedical implants remains a complex problem in the medical field. We aimed to determine the effects of electrochemical anodization (60V, 2h) and thermal oxidation (600°C) on the corrosive behavior of Ti-6Al-4V, with serum proteins, at physiological temperature. Anodization produced a mixture of anatase and amorphous TiO2 nanopores and nanotubes, while the annealing process yielded an anatase/rutile mixture of TiO2 nanopores and nanotubes. The surface area was analyzed by the Brunauer-Emmett-Teller method and was estimated to be 3 orders of magnitude higher than that of polished control samples. Corrosion resistance was evaluated on the parameters of open circuit potential, corrosion potential, corrosion current density, passivation current density, polarization resistance and equivalent circuit modeling. Samples both anodized and thermally oxidized exhibited shifts of open circuit potential and corrosion potential in the noble direction, indicating a more stable nanoporous/nanotube layer, as well as lower corrosion current densities and passivation current densities than the smooth control. They also showed increased polarization resistance and diffusion limited charge transfer within the bulk oxide layer. The treatment groups studied can be ordered from greatest corrosion resistance to least as Anodized+Thermally Oxidized > Anodized > Smooth > Thermally Oxidized for the conditions investigated. This study concludes that anodized surface has a potential to prevent long term implant failure due to corrosion in a complex in-vivo environment.

  12. Effect of Hydrogen Plasma on Model Corrosion Layers of Bronze

    NASA Astrophysics Data System (ADS)

    Fojtíková, P.; Sázavská, V.; Mika, F.; Krčma, F.

    2016-05-01

    Our work is about plasmachemical reduction of model corrosion layers. The model corrosion layers were produced on bronze samples with size of 10 × 10 × 5 mm3, containing Cu and Sn. Concentrated hydrochloric acid was used as a corrosive environment. The application of reduction process in low-pressure low-temperature hydrogen plasma followed. A quartz cylindrical reactor with two outer copper electrodes was used. Plasma discharge was generated in pure hydrogen by a RF generator. Each corroded sample was treated in different conditions (supplied power and a continual or pulsed regime with a variable duty cycle mode). Process monitoring was ensured by optical emission spectroscopy. After treatment, samples were analyzed by SEM and EDX.

  13. Corrosion resistance characterization of porous alumina membrane supports

    SciTech Connect

    Dong Yingchao; Lin Bin; Zhou Jianer; Zhang Xiaozhen; Ling Yihan; Liu Xingqin; Meng Guangyao; Hampshire, Stuart

    2011-04-15

    Tubular porous alumina ceramic membrane supports were fabricated by an extrusion-drying-sintering process and then characterized in detail in terms of corrosion resistance in both H{sub 2}SO{sub 4} and NaOH aqueous solutions. Variations in the properties of the alumina supports such as mass loss percent, mechanical strength, open porosity and pore size distribution were studied before and after corrosion under different conditions. In addition, the microstructures were analyzed using scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction before and after corrosion. The fabricated porous alumina supports offer possibilities for some potential applications as micro-filtration or ultra-filtration membrane supports, as well as in the pre-treatment of strongly acidic industrial waste-liquids. - Research highlights: {yields} Porous alumina membrane supports fabricated by extrusion-drying-sintering process. {yields} Corrosion resistance in 20 wt.% H{sub 2}SO{sub 4} and 1, 5, 10 wt.% NaOH aqueous solutions. {yields} Rapid mass loss and loss of flexural strength occurred in hot NaOH solution. {yields} Resistant to strong acid corrosion with low mass loss, low flexural strength loss. {yields} Porous alumina supports have potential for treatment of strong acid waste liquids.

  14. Exopolysaccharides from lactic acid bacteria as corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    Ignatova-Ivanova, Tsveteslava; Ivanov, Radoslav

    2016-03-01

    Bacterial EPSs (exopolysaccharides) are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus sp. are presented and discussed. Lactobacillus delbrueckii K27, Lactobacillus delbrueckii B8, Lactobacillus delbrueckii KO43, Lactobacillus delbrueckii K3, Lactobacillus delbrueckii K15 and Lactobacillus delbrueckii K17 was obtained from Collection of Department of General and Applied Microbiology, Sofia University. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% lacose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM (scanning electron microscopy) JSM 5510. It could be underlined that 10% sucrose, 10% lactose and 10% maltose in the media stimulated the process of protection of corrosion.

  15. Inter-relationships between corrosion and mineral-scale deposition in aqueous systems.

    PubMed

    Hodgkiess, T

    2004-01-01

    The processes of corrosion and scale deposition in natural and process waters are often linked and this paper considers a number of instances of interactions between the two phenomena. In some circumstances a scale layer (e.g. calcium carbonate) can be advantageously utilised as a corrosion-protection coating on components and this feature has been exploited for many decades in the conditioning of water to induce spontaneous precipitation of a scale layer upon the surfaces of engineering equipment. The electrochemical mechanisms associated with some corrosion and corrosion-control processes can promote alkaline-scale deposition directly upon component surfaces. This is a feature that can be exploited in the operation of cathodic protection (CP) of structures and components submerged in certain types of water (e.g. seawater). Similar phenomena can occur during bi-metallic corrosion and a case study, involving carbon steel/stainless steel couples in seawater, is presented. Additional complexities pertain during cyclic loading of submerged reinforced concrete members in which scale deposition may reduce the severity of fatigue stresses but can be associated with severe corrosion damage to embedded reinforcing steel. Also considered are scale-control/corrosion interactions in thermal desalination plant and an indirect consequence of the scale-control strategy on vapourside corrosion is discussed.

  16. Inter-relationships between corrosion and mineral-scale deposition in aqueous systems.

    PubMed

    Hodgkiess, T

    2004-01-01

    The processes of corrosion and scale deposition in natural and process waters are often linked and this paper considers a number of instances of interactions between the two phenomena. In some circumstances a scale layer (e.g. calcium carbonate) can be advantageously utilised as a corrosion-protection coating on components and this feature has been exploited for many decades in the conditioning of water to induce spontaneous precipitation of a scale layer upon the surfaces of engineering equipment. The electrochemical mechanisms associated with some corrosion and corrosion-control processes can promote alkaline-scale deposition directly upon component surfaces. This is a feature that can be exploited in the operation of cathodic protection (CP) of structures and components submerged in certain types of water (e.g. seawater). Similar phenomena can occur during bi-metallic corrosion and a case study, involving carbon steel/stainless steel couples in seawater, is presented. Additional complexities pertain during cyclic loading of submerged reinforced concrete members in which scale deposition may reduce the severity of fatigue stresses but can be associated with severe corrosion damage to embedded reinforcing steel. Also considered are scale-control/corrosion interactions in thermal desalination plant and an indirect consequence of the scale-control strategy on vapourside corrosion is discussed. PMID:14982172

  17. Atomistic Modeling of Corrosion Events at the Interface between a Metal and Its Environment

    DOE PAGES

    Taylor, Christopher D.

    2012-01-01

    Atomistic simulation is a powerful tool for probing the structure and properties of materials and the nature of chemical reactions. Corrosion is a complex process that involves chemical reactions occurring at the interface between a material and its environment and is, therefore, highly suited to study by atomistic modeling techniques. In this paper, the complex nature of corrosion processes and mechanisms is briefly reviewed. Various atomistic methods for exploring corrosion mechanisms are then described, and recent applications in the literature surveyed. Several instances of the application of atomistic modeling to corrosion science are then reviewed in detail, including studies ofmore » the metal-water interface, the reaction of water on electrified metallic interfaces, the dissolution of metal atoms from metallic surfaces, and the role of competitive adsorption in controlling the chemical nature and structure of a metallic surface. Some perspectives are then given concerning the future of atomistic modeling in the field of corrosion science.« less

  18. WASTE PACKAGE CORROSION STUDIES USING SMALL MOCKUP EXPERIMENTS

    SciTech Connect

    B.E. Anderson; K.B. Helean; C.R. Bryan; P.V. Brady; R.C. Ewing

    2005-10-19

    The corrosion of spent nuclear fuel and subsequent mobilization of radionuclides is of great concern in a geologic repository, particularly if conditions are oxidizing. Corroding A516 steel may offset these transport processes within the proposed waste packages at the Yucca Mountain Repository (YMR) by retaining radionuclides, creating locally reducing conditions, and reducing porosity. Ferrous iron, Fe{sup 2+}, has been shown to reduce UO{sub 2}{sup 2+} to UO{sub 2(s)} [1], and some ferrous iron-bearing ion-exchange materials adsorb radionuclides and heavy metals [2]. Of particular interest is magnetite, a potential corrosion product that has been shown to remove TcO{sub 4}{sup -} from solution [3]. Furthermore, if Fe{sup 2+} minerals, rather than fully oxidized minerals such as goethite, are produced during corrosion, then locally reducing conditions may be present. High electron availability leads to the reduction and subsequent immobilization of problematic dissolved species such as TcO{sub 4}{sup -}, NpO{sub 2}{sup +}, and UO{sub 2}{sup 2+} and can also inhibit corrosion of spent nuclear fuel. Finally, because the molar volume of iron material increases during corrosion due to oxygen and water incorporation, pore space may be significantly reduced over long time periods. The more water is occluded, the bulkier the corrosion products, and the less porosity is available for water and radionuclide transport. The focus of this paper is on the nature of Yucca Mountain waste package steel corrosion products and their effects on local redox state, radionuclide transport, and porosity.

  19. Investigation of corrosion of welded joints of austenitic and duplex stainless steels

    NASA Astrophysics Data System (ADS)

    Topolska, S.

    2016-08-01

    Investigation of corrosion resistance of materials is one of the most important tests that allow determining their functional properties. Among these tests the special group consist electrochemical investigations, which let to accelerate the course of the process. These investigations allow rapidly estimating corrosion processes occurring in metal elements under the influence of the analysed environment. In the paper are presented results of investigations of the resistance to pitting corrosion of the steel of next grades: austenitic 316L and duplex 2205. It was also analysed the corrosion resistance of welded joints of these grades of steel. The investigations were conducted in two different corrosion environments: in the neutral one (3.5 % sodium chloride) and in the aggressive one (0.1 M sulphuric acid VI). The obtained results indicate different resistance of analysed grades of steel and their welded joints in relation to the corrosion environment. The austenitic 316L steel characterizes by the higher resistance to the pitting corrosion in the aggressive environment then the duplex 2205 steel. In the paper are presented results of potentiodynamic tests. They showed that all the specimens are less resistant to pitting corrosion in the environment of sulphuric acid (VI) than in the sodium chloride one. The 2205 steel has higher corrosion resistance than the 316L stainless steel in 3.5% NaCl. On the other hand, in 0.1 M H2SO4, the 316L steel has a higher corrosion resistance than the 2205 one. The weld has a similar, very good resistance to pitting corrosion like both steels.

  20. DEPOSITION TANK CORROSION TESTING FOR ENHANCED CHEMICAL CLEANING POST OXALIC ACID DESTRUCTION

    SciTech Connect

    Mickalonis, J.

    2011-08-29

    An Enhanced Chemical Cleaning (ECC) process is being developed to aid in the high level waste tank closure at the Savannah River Site. The ECC process uses an advanced oxidation process (AOP) to destroy the oxalic acid that is used to remove residual sludge from a waste tank prior to closure. The AOP process treats the dissolved sludge with ozone to decompose the oxalic acid through reactions with hydroxyl radicals. The effluent from this oxalic acid decomposition is to be sent to a Type III waste tank and may be corrosive to these tanks. As part of the hazardous simulant testing that was conducted at the ECC vendor location, corrosion testing was conducted to determine the general corrosion rate for the deposition tank and to assess the susceptibility to localized corrosion, especially pitting. Both of these factors impact the calculation of hydrogen gas generation and the structural integrity of the tanks, which are considered safety class functions. The testing consisted of immersion and electrochemical testing of A537 carbon steel, the material of construction of Type III tanks, and 304L stainless steel, the material of construction for transfer piping. Tests were conducted in solutions removed from the destruction loop of the prototype ECC set up. Hazardous simulants, which were manufactured at SRNL, were used as representative sludges for F-area and H-area waste tanks. Oxalic acid concentrations of 1 and 2.5% were used to dissolve the sludge as a feed to the ECC process. Test solutions included the uninhibited effluent, as well as the effluent treated for corrosion control. The corrosion control options included mixing with an inhibited supernate and the addition of hydroxide. Evaporation of the uninhibited effluent was also tested since it may have a positive impact on reducing corrosion. All corrosion testing was conducted at 50 C. The uninhibited effluent was found to increase the corrosion rate by an order of magnitude from less than 1 mil per year (mpy

  1. Report on accelerated corrosion studies.

    SciTech Connect

    Mowry, Curtis Dale; Glass, Sarah Jill; Sorensen, Neil Robert

    2011-03-01

    Sandia National Laboratories (SNL) conducted accelerated atmospheric corrosion testing for the U.S. Consumer Product Safety Commission (CPSC) to help further the understanding of the development of corrosion products on conductor materials in household electrical components exposed to environmental conditions representative of homes constructed with problem drywall. The conditions of the accelerated testing were chosen to produce corrosion product growth that would be consistent with long-term exposure to environments containing humidity and parts per billion (ppb) levels of hydrogen sulfide (H{sub 2}S) that are thought to have been the source of corrosion in electrical components from affected homes. This report documents the test set-up, monitoring of electrical performance of powered electrical components during the exposure, and the materials characterization conducted on wires, screws, and contact plates from selected electrical components. No degradation in electrical performance (measured via voltage drop) was measured during the course of the 8-week exposure, which was approximately equivalent to 40 years of exposure in a light industrial environment. Analyses show that corrosion products consisting of various phases of copper sulfide, copper sulfate, and copper oxide are found on exposed surfaces of the conductor materials including wires, screws, and contact plates. The morphology and the thickness of the corrosion products showed a range of character. In some of the copper wires that were observed, corrosion product had flaked or spalled off the surface, exposing fresh metal to the reaction with the contaminant gasses; however, there was no significant change in the wire cross-sectional area.

  2. Corrosion Assessment of Candidate Materials for the SHINE Subcritical Assembly Vessel and Components FY14 Report

    SciTech Connect

    Pawel, Steven J.

    2014-10-01

    Laboratory corrosion testing of candidate alloys—including Zr-4 and Zr-2.5Nb representing the target solution vessel, and 316L, 2304, 304L, and 17-4 PH stainless steels representing process piping and balance-of-plant components—was performed in support of the proposed SHINE process to produce 99Mo from low-enriched uranium. The test solutions used depleted uranyl sulfate in various concentrations and incorporated a range of temperatures, excess sulfuric acid concentrations, nitric acid additions (to simulate radiolysis product generation), and iodine additions. Testing involved static immersion of coupons in solution and in the vapor above the solution, and was extended to include planned-interval tests to examine details associated with stainless steel corrosion in environments containing iodine species. A large number of galvanic tests featuring couples between a stainless steel and a zirconium-based alloy were performed, and limited vibratory horn testing was incorporated to explore potential erosion/corrosion features of compatibility. In all cases, corrosion of the zirconium alloys was observed to be minimal, with corrosion rates based on weight loss calculated to be less than 0.1 mil/year with no change in surface roughness. The resulting passive film appeared to be ZrO2 with variations in thickness that influence apparent coloration (toward light brown for thicker films). Galvanic coupling with various stainless steels in selected exposures had no discernable effect on appearance, surface roughness, or corrosion rate. Erosion/corrosion behavior was the same for zirconium alloys in uranyl sulfate solutions and in sodium sulfate solutions adjusted to a similar pH, suggesting there was no negative effect of uranium resulting from fluid dynamic conditions aggressive to the passive film. Corrosion of the candidate stainless steels was similarly modest across the entire range of exposures. However, some sensitivity to corrosion of the stainless steels was

  3. Effect of Corrosion Film Composition and Structure on the Corrosion Kinetics of Ni-Cr-Fe Alloys in High Temperature Water

    SciTech Connect

    P.M. Rosecrans; N. Lewis; D.J. Duquette

    2002-02-27

    Nickel alloys such as Alloy 600 undergo Stress Corrosion Cracking (SCC) in pure water at temperatures between about 260 C and the critical point. Increasing the level of Cr in Ni-Fe-Cr alloys increases SCC resistance in aerated and deaerated water. The mechanism is not understood. The effect of Cr composition on oxide microstructure and corrosion kinetics of Ni-Fe-Cr alloys was determined experimentally, to evaluate whether the anodic dissolution model for SCC can account for the effect of Cr on SCC. The alloy corrosion rate and corrosion product oxide microstructure is strongly influenced by the Cr composition. Corrosion kinetics are parabolic and influenced by chromium concentration, with the parabolic constant first increasing then decreasing as Cr increases from 5 to 39%. Surface analyses using Analytical Electron microscopy (AEM) and Auger Electron Spectroscopy (AES) show that the corrosion product film that forms initially on all alloys exposed to high purity high temperature water is a nickel rich oxide. With time, the amount of chromium in the oxide film increases and corrosion proceeds toward the formation of the more thermodynamically stable spinel or hexagonal Cr-rich oxides, similar to high temperature gaseous oxidation. Due to the slower diffusion kinetics at the temperatures of water corrosion compared to those in high temperature gaseous oxidation, however, the films remain as a mixture of NiO, mixed Ni, Fe and Cr spinels, NiCrO{sub 3} and FeCrO{sub 3}. As the amount of Cr in the film increases and the nature of the film changes from NiO to spinel or hexagonal oxides, cation diffusion through the films slows, slowing the corrosion rate. These observations are qualitatively consistent with an anodic dissolution SCC mechanism. However, parametric modeling of the SCC growth process, applying available creep, oxide rupture strain and corrosion kinetics data, indicates that the anodic dissolution mechanism accounts for only a fraction of the effect of Cr

  4. Fe sub 3 Al-type iron aluminides: Aqueous corrosion properties in a range of electrolytes and slow-strain-rate ductilities during aqueous corrosion

    SciTech Connect

    Buchanan, R.A.; Kim, J.G. . Dept. of Materials Science and Engineering)

    1992-08-01

    The Fe{sub 3}Al-type iron aluminides have undergone continued development at the Oak Ridge National Laboratory for enhancement of mechanical and corrosion properties. Improved alloys and thermomechanical processing methods have evolved. The overall purpose of the project herein described was to evaluate the aqueous corrosion properties of the most recent alloy compositions in a wide range of possibly-aggressive solutions and under several different types of corrosion-test conditions. The work supplements previous aqueous-corrosion studies on iron aluminides by the present authors. Four stages of this one-year aqueous-corrosion investigation are described. First the corrosion properties of selected iron aluminides were evaluated by means of electrochemical tests and longer-time immersion tests in a range of acidic, basic and chloride solutions. Theses tests were performed under non-crevice conditions, i.e. the specimens were not designed to contain crevice geometries. Second, the iron-aluminide alloy that proved most resistance to chloride-induced localized corrosion under non-crevice conditions was further evaluated under more-severe crevice conditions by electrochemical and immersion testing. Third, in order to study the relative roles of Fe, Al, Cr and Mo in the formation of passive films, the chemical compositions of passive films were determined by X-ray photoelectron spectroscopy (XPS). And fourth, in order to study aqueous-corrosion effects on the ductilities of iron aluminides as related to hydrogen embrittlement and/or stress-corrosion cracking, slow-strain-rate corrosion (SSRC) tests were conducted over a range of electrochemical potentials.

  5. Fe{sub 3}Al-type iron aluminides: Aqueous corrosion properties in a range of electrolytes and slow-strain-rate ductilities during aqueous corrosion

    SciTech Connect

    Buchanan, R.A.; Kim, J.G.

    1992-08-01

    The Fe{sub 3}Al-type iron aluminides have undergone continued development at the Oak Ridge National Laboratory for enhancement of mechanical and corrosion properties. Improved alloys and thermomechanical processing methods have evolved. The overall purpose of the project herein described was to evaluate the aqueous corrosion properties of the most recent alloy compositions in a wide range of possibly-aggressive solutions and under several different types of corrosion-test conditions. The work supplements previous aqueous-corrosion studies on iron aluminides by the present authors. Four stages of this one-year aqueous-corrosion investigation are described. First the corrosion properties of selected iron aluminides were evaluated by means of electrochemical tests and longer-time immersion tests in a range of acidic, basic and chloride solutions. Theses tests were performed under non-crevice conditions, i.e. the specimens were not designed to contain crevice geometries. Second, the iron-aluminide alloy that proved most resistance to chloride-induced localized corrosion under non-crevice conditions was further evaluated under more-severe crevice conditions by electrochemical and immersion testing. Third, in order to study the relative roles of Fe, Al, Cr and Mo in the formation of passive films, the chemical compositions of passive films were determined by X-ray photoelectron spectroscopy (XPS). And fourth, in order to study aqueous-corrosion effects on the ductilities of iron aluminides as related to hydrogen embrittlement and/or stress-corrosion cracking, slow-strain-rate corrosion (SSRC) tests were conducted over a range of electrochemical potentials.

  6. Continuous acoustic emission monitoring of reinforced concrete under accelerated corrosion

    NASA Astrophysics Data System (ADS)

    Di Benedetti, M.; Loreto, G.; Nanni, A.; Matta, F.; Gonzalez-Nunez, M. A.

    2011-04-01

    The development of techniques capable of evaluating deterioration of reinforced concrete (RC) structures is instrumental to the advancement of techniques for the structural health monitoring (SHM) and service life estimate for constructed facilities. One of the main causes leading to degradation of RC is the corrosion of the steel reinforcement. This process can be modeled phenomenologically, while laboratory tests aimed at studying durability responses are typically accelerated in order to provide useful results within a realistic period of time. To assess the condition of damage in RC, a number of nondestructive methods have been recently studied. Acoustic emission (AE) is emerging as a nondestructive tool to detect the onset and progression of deterioration mechanisms. In this paper, the development of accelerated corrosion and continuous AE monitoring test set-up for RC specimens are presented. Relevant information are provided with regard to the characteristics of the corrosion circuit, continuous measurement and acquisition of corrosion potential, selection of AE sensors and AE parameter setting. The effectiveness of the setup in detecting and characterizing the initiation and progression of the corrosion phenomenon is discussed on the basis of preliminary results from small-scale, pre-cracked RC specimens, which are representative of areas near the clear cover in typical RC bridge members.

  7. Corrosion fatigue of biomedical metallic alloys: mechanisms and mitigation.

    PubMed

    Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

    2012-03-01

    Cyclic stresses are often related to the premature mechanical failure of metallic biomaterials. The complex interaction between fatigue and corrosion in the physiological environment has been subject of many investigations. In this context, microstructure, heat treatments, plastic deformation, surface finishing and coatings have decisive influence on the mechanisms of fatigue crack nucleation and growth. Furthermore, wear is frequently present and contributes to the process. However, despite all the effort at elucidating the mechanisms that govern corrosion fatigue of biomedical alloys, failures continue to occur. This work reviews the literature on corrosion-fatigue-related phenomena of Ti alloys, surgical stainless steels, Co-Cr-Mo and Mg alloys. The aim was to discuss the correlation between structural and surface aspects of these materials and the onset of fatigue in the highly saline environment of the human body. By understanding such correlation, mitigation of corrosion fatigue failure may be achieved in a reliable scientific-based manner. Different mitigation methods are also reviewed and discussed throughout the text. It is intended that the information condensed in this article should be a valuable tool in the development of increasingly successful designs against the corrosion fatigue of metallic implants.

  8. Assessment of corrosion rate in prestressed concrete with acoustic emission

    NASA Astrophysics Data System (ADS)

    Mangual, Jesé; ElBatanouny, Mohamed K.; Vélez, William; Ziehl, Paul; Matta, Fabio; González, Miguel

    2011-04-01

    Acoustic Emission (AE) sensing was employed to assess the rate of corrosion of steel strands in small scale concrete block specimens. The corrosion process was accelerated in a laboratory environment using a potentiostat to supply a constant potential difference with a 3% NaCl solution as the electrolyte. The embedded prestressing steel strand served as the anode, and a copper plate served as the cathode. Corrosion rate, half-cell potential measurements, and AE activity were recorded continuously throughout each test and examined to assess the development of corrosion and its rate. At the end of each test the steel strands were cleaned and re-weighed to determine the mass loss and evaluate it vis-á-vis the AE data. The initiation and propagation phases of corrosion were correlated with the percentage mass loss of steel and the acquired AE signals. Results indicate that AE monitoring may be a useful aid in the detection and differentiation of the steel deterioration phases, and estimation of the locations of corroded areas.

  9. Sulfuric acid-induced corrosion of aluminum surfaces

    SciTech Connect

    Dai, Q.; Freedman, A.; Robinson, G.N.

    1995-12-01

    The sulfuric acid-induced corrosion of smooth (2 nm average roughness) aluminum surfaces has been studied in real times using an in situ Fourier transform infrared reflection absorption spectrometer and a quartz crystal microbalance. Submicron thick, 35 to 55 weight percent (5 to 12 molal), sulfuric acid films were formed on room temperature metal surfaces by the reaction of gas-phase SO{sub 3} and H{sub 2}O vapor in a flowing gas system at a total pressure of {approximately}200 Torr. The deposition of the acid films and subsequent changes in their chemical composition resulting from corrosion of the aluminum substrate could be monitored using characteristic infrared absorption features. The corrosion process always significantly perturbed the spectral signature of the films from that which was observed on inert gold surfaces. Using changes in spectral features that are linked to the production of Al{sup 3+} as indicators of corrosion, the authors conclude the rate of corrosion of the metal is strongly enhanced by both higher relative humidities and increased rates of sulfuric acid deposition.

  10. Hanford transuranic storage corrosion review

    SciTech Connect

    Nelson, J.L.; Divine, J.R.

    1980-12-01

    The rate of atmospheric corrosion of the transuranic (TRU) waste drums at the US Department of Energy's Hanford Project, near Richland, Washington, was evaluated by Pacific Northwest Laboratory (PNL). The rate of corrosion is principally contingent upon the effects of humidity, airborne pollutants, and temperature. Results of the study indicate that actual penetration of barrels due to atmospheric corrosion will probably not occur within the 20-year specified recovery period. Several other US burial sites were surveyed, and it appears that there is sufficient uncertainty in the available data to prevent a clearcut statement of the corrosion rate at a specific site. Laboratory and site tests are recommended before any definite conclusions can be made. The corrosion potential at the Hanford TRU waste site could be reduced by a combination of changes in drum materials (for example, using galvanized barrels instead of the currently used mild steel barrels), environmental exposure conditions (for example, covering the barrels in one of numerous possible ways), and storage conditions (for example, separating the layers of barrels with slats of wood instead of sheets of plywood).

  11. Corrosion effects on friction factors

    SciTech Connect

    Magleby, H.L.; Shaffer, S.J.

    1996-03-01

    This paper presents the results of NRC-sponsored material specimen tests that were performed to determine if corrosion increases the friction factors of sliding surfaces of motor-operated gate valves, which could require higher forces to close and open safety-related valves when subjected to their design basis differential pressures. Friction tests were performed with uncorroded specimens and specimens subjected to accelerated corrosion. Preliminary tests at ambient conditions showed that corrosion increased the friction factors, indicating the need for additional tests duplicating valve operating parameters at hot conditions. The additional tests showed friction factors of corroded specimens were 0.1 to 0.2 higher than for uncorroded specimens, and that the friction factors of the corroded specimens were not very dependent on contact stress or corrosion film thickness. The measured values of friction factors for the three corrosion films tested (simulating three operating times) were in the range of 0.3 to 0.4. The friction factor for even the shortest simulated operating time was essentially the same as the others, indicating that the friction factors appear to reach a plateau and that the plateau is reached quickly.

  12. Wear and corrosion performance of metallurgical coatings in sodium

    SciTech Connect

    Johnson, R.N.; Farwick, D.G.

    1980-04-24

    The friction, wear, and corrosion performance of several metallurgical coatings in 200 to 650/sup 0/C sodium are reviewed. Emphasis is placed on those coatings which have successfully passed the qualification tests necessary for acceptance in breeder reactor environments. Tests include friction, wear, corrosion, thermal cycling, self-welding, and irradiation exposure under as-prototypic-as-possible service conditions. Materials tested were coatings of various refractory metal carbides in metallic binders, nickel-base and cobalt-base alloys and intermetallic compounds such as the aluminides and borides. Coating processes evaluated included plasma spray, detonation gun, sputtering, spark-deposition, and solid-state diffusion.

  13. Corrosion and Preservation of Bronze Artifacts.

    ERIC Educational Resources Information Center

    Walker, Robert

    1980-01-01

    Reviews chemical information relating to the corrosion of bronze artifacts. Properties of copper alloys are reviewed, with a thorough discussion of the specialized properties of bronze. Techniques to reduce or eliminate corrosion are listed. (CS)

  14. Microencapsulation of Corrosion Indicators for Smart Coatings

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.; Calle, Luz M.; Hanna,Joshua S.; Rawlins, James W.

    2011-01-01

    A multifunctional smart coating for the autonomous detection, indication, and control of corrosion is been developed based on microencapsulation technology. This paper summarizes the development, optimization, and testing of microcapsules specifically designed for early detection and indication of corrosion when incorporated into a smart coating. Results from experiments designed to test the ability of the microcapsules to detect and indicate corrosion, when blended into several paint systems, show that these experimental coatings generate a color change, indicative of spot specific corrosion events, that can be observed with the naked eye within hours rather than the hundreds of hours or months typical of the standard accelerated corrosion test protocols.. Key words: smart coating, corrosion detection, microencapsulation, microcapsule, pH-sensitive microcapsule, corrosion indicator, corrosion sensing paint

  15. Corrosion of nickel-base alloys

    SciTech Connect

    Scarberry, R.C.

    1985-01-01

    The volume consists of three tutorial lectures and 18 contributed papers. The three tutorial lectures provide state-of-the-art background on the physical metallurgy of nickel-base alloys as it relates to corrosion. Also featured are the mechanisms and applications of these alloys and an insight into the corrosion testing techniques. The three tutorial lecture papers will help acquaint newcomers to this family of alloys with a thorough overview. The contributed papers are categorized into four major topics: general corrosion, stress corrosion cracking, fatigue and localized corrosion. Each topic is key-noted by one invited lecture followed by several contributed papers. The papers in the general corrosion section are wide ranging and cover the aspects of material selection, development of galvanic series in corrosive environments, corrosion resistance characteristics, hydrogen permeation and hydrogen embrittlement of nickel and some nickel-base alloys.

  16. Surface Corrosion of Nanoscaled Hydroxyapatite During an In Vivo Experiment.

    PubMed

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong

    2015-10-01

    Hydroxyapatite (HA) is widely used as a bioactive ceramics as it forms a chemical bond with bone. However, the drawback to using this material is its inferior mechanical properties. In this research, surface corrosion and disintegration of nanoscaled HA in a dog were studied, and the mechanism by which phase-pure HA dissolved in vivo was investigated. Biological properties of HA in vivo are affected by the grain-boundary dissolution followed by a surface corrosion and microstructural disintegration. This kind of dissolution process, apparently evidenced at the grain boundary, causes particle generation, which indicates that both long-term bone in-growth and mechanical properties can dramatically deteriorate. Implant dissolution by osteoclasts in vivo is also observed on the surface of hydroxyapatite. Implant surface showed an aggressive corrosion by an osteoclast resorption. Severe and deeper dissolution underwent close to osteoclast resulting in formation of smaller and more round particle shape.

  17. Techniques for the detection of corrosion under insulation

    SciTech Connect

    Matulewicz, W.

    1996-07-01

    The exterior corrosion of piping or vessels under insulation, typically due to water ingress, has been a concern for many years in the process industries. In the past, due to economic constraints, the monitoring or detection for corrosion under insulation (CUI) has not received a high priority. Visual or ultrasonic thickness checks were the only methods generally applied for inspection. Rapid and economic methods for overall detection of corrosion under insulation were virtually nonexistent. A recent issuance of the American Petroleum Institute`s ``Piping Inspection Code,`` API 570 has promoted renewed interest for piping system inspections. A brief review of this code along with the feasibility and field application of s stems are reviewed for a means of CUI detection.

  18. Long-Term Underground Corrosion of Stainless Steels

    SciTech Connect

    M. K. Adler Flitton; T. S. Yoder

    2007-03-01

    In 1970, the National Institute of Standards and Technology (NIST) implemented the most ambitious and comprehensive long-term corrosion behavior test to date for stainless steels in soil environments. Over thirty years later, one of the six test sites was targeted to research subsurface contamination and transport processes in the vadose and saturated zones. This research directly applies to environmental management operational corrosion issues and long term stewardship scientific needs for understanding the behavior of waste forms and their near-field contaminant transport of chemical and radiological contaminants at nuclear disposal sites. This paper briefly describes the ongoing research and the corrosion analysis results of the stainless steel plate specimens recovered from the partial recovery of the first test site.

  19. Alternatives to reduce corrosion of carbon steel storage drums

    SciTech Connect

    Zirker, L.R.; Beitel, G.A.

    1995-11-01

    The major tasks of this research were (a) pollution prevention opportunity assessments on the overpacking operations for failed or corroded drums, (b) research on existing container corrosion data, (c) investigation of the storage environment of the new Resource Conservation and Recovery Act Type II storage modules, (d) identification of waste streams that demonstrate deleterious corrosion affects on drum storage life, and (e) corrosion test cell program development. Twenty-one waste streams from five US Department of Energy (DOE) sites within the DOE Complex were identified to demonstrate a deleterious effect to steel storage drums. The major components of these waste streams include acids, salts, and solvent liquids, sludges, and still bottoms. The solvent-based waste streams typically had the shortest time to failure: 0.5 to 2 years. The results of this research support the position that pollution prevention evaluations at the front end of a project or process will reduce pollution on the back end.

  20. Corrosion probes for fireside monitoring in coal-fired boilers

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Eden, David A.; Cayard, Michael S.

    2004-01-01

    Electrochemical corrosion rate (ECR) probes were constructed and exposed along with mass loss coupons in a N2/O2/CO2/H2O environment to determine ECR probe operating characteristics. Temperatures ranged from 450 to 600 C and both ECR probes and mass loss coupons were coated with ash. Results are presented in terms of the probe response to temperature, the measured zero baseline, and the quantitative nature of the probes. The effect of Stern-Geary constant and the choice of electrochemical technique used to measure the corrosion rate are also discussed. ECR probe corrosion rates were a function of time, temperature, and process environment and were found to be quantitative for some test conditions. Measured Stern-Geary constants averaged 0.0141 V/decade and the linear polarization technique was found to be more quantitative than the electrochemical noise technique.