Sample records for develop corrosion resistant

  1. Shop fabricated corrosion-resistant underground storage tanks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Geyer, W.B.; Stellmach, W.A.

    1995-12-31

    Integral corrosion resistance has long been incorporated into shop fabricated steel underground storage tank design. Since 1969, an industry standard has been the sti-P{sub 3}{reg_sign} (P3) tank. However, the past decade has seen the development of several alternative corrosion resistant and secondary containment technologies. Fiberglass-coated steel composite tanks, and jacketed tanks utilizing various materials as a secondary wall, provide corrosion resistance without the cathodic protection monitoring requirements mandated by the EPA for single-wall P3 tanks. On the other hand, the P3 tank is the only tank technology commonly marketed today with an integral ability to verify its corrosion resistance overmore » the life of the tank. Many existing USTs remain to be replaced or upgraded with corrosion resistance (and other requirements) by the end of 1998. Steel tanks built and installed prior to the advent of pre-engineered, factory-supplied protection against corrosion can be retrofitted with cathodic protection or can be internally lined. Specific installation standards developed by the steel tank industry and the petroleum industry must be followed so as to assure the integrity of the various corrosion resistant technologies developed by the Steel Tank Institute. The technologies describes in this paper will ensure compliance with the corrosion protection requirements of new storage tanks.« less

  2. Effects of grain size on the corrosion resistance of pure magnesium by cooling rate-controlled solidification

    NASA Astrophysics Data System (ADS)

    Liu, Yichi; Liu, Debao; You, Chen; Chen, Minfang

    2015-09-01

    The aim of this study was to investigate the effect of grain size on the corrosion resistance of pure magnesium developed for biomedical applications. High-purity magnesium samples with different grain size were prepared by the cooling rate-controlled solidification. Electrochemical and immersion tests were employed to measure the corrosion resistance of pure magnesium with different grain size. The electrochemical polarization curves indicated that the corrosion susceptibility increased as the grain size decrease. However, the electrochemical impedance spectroscopy (EIS) and immersion tests indicated that the corrosion resistance of pure magnesium is improved as the grain size decreases. The improvement in the corrosion resistance is attributed to refine grain can produce more uniform and density film on the surface of sample.

  3. Evaluation of the optoelectronic properties and corrosion behavior of Al2O3-doped ZnO films prepared by dc pulsed magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Zubizarreta, C.; Berasategui, E. G.; Bayón, R.; Escobar Galindo, R.; Barros, R.; Gaspar, D.; Nunes, D.; Calmeiro, T.; Martins, R.; Fortunato, E.; Barriga, J.

    2014-12-01

    The main requirements for transparent conducting oxide (TCO) films acting as electrodes are a high transmission rate in the visible spectral region and low resistivity. However, in many cases, tolerance to temperature and humidity exposure is also an important requirement to be fulfilled by the TCOs to assure proper operation and durability. Besides improving current encapsulation methods, the corrosion resistance of the developed TCOs must also be enhanced to warrant the performance of optoelectronic devices. In this paper the performance of aluminum-doped zinc oxide (AZO) films deposited by pulsed dc magnetron sputtering has been studied. Structure, optical transmittance/reflectance, electrical properties (resistivity, carrier concentration and mobility) and corrosion resistance of the developed coatings have been analyzed as a function of the doping of the target and the coating thickness. Films grown from a 2.0 wt% Al2O3 target with a thickness of approximately 1 µm showed a very low resistivity of 6.54  ×  10-4 Ωcm and a high optical transmittance in the visible range of 84%. Corrosion studies of the developed samples have shown very low corrosion currents (nanoamperes), very high corrosion resistances (in the order of 107 Ω) and very high electrochemical stability, indicating no tendency for electrochemical corrosion degradation.

  4. Hot corrosion of four superalloys - HA-188, S-57, IN-617, and TD-NiCrAl

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.

    1979-01-01

    Cyclic oxidation and hot corrosion tests of two cobalt-base and two nickel-base alloys are reported. The alloys were exposed to maximum temperatures of 900 and 1000 C in a Mach 0.3 burner rig whose flame was doped with various concentrations of sea salt and sodium sulfate for hot corrosion tests. The test data were subjected to a regression analysis for the development of model equations relating corrosion to temperature and for the effects of salt concentration and composition on corrosion. The corrosion resistance varied with temperature, sea salt concentration, and salt composition, concluding that the S-57 cobalt-base alloy was the most hot corrosion-resistant alloy, and the TD-NiCrAl nickel-base alloy was the least resistant. However, under straight oxidation conditions, the TD-NiCrAl was most resistant, while S-57 was the least resistant alloy.

  5. 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.

  6. Imparting passivity to vapor deposited magnesium alloys

    NASA Astrophysics Data System (ADS)

    Wolfe, Ryan C.

    Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning electron microscope. The corrosion rate of the nonequilibrium sputtered alloys, as determined by polarization resistance, is significantly reduced compared to the most corrosion resistant commercial magnesium alloys. The open circuit potentials of the sputter deposited alloys are significantly more noble compared to commercial, equilibrium phase magnesium alloys. Galvanic corrosion susceptibility has also been considerably reduced. Nonequilibrium magnesium-yttrium-titanium alloys have been shown to achieve passivity autonomously by alteration of the composition chemistry of the surface oxide/hydroxide layer. Self-healing properties are also evident, as corrosion propagation can be arrested after initial pitting of the material. A clear relationship exists between the corrosion resistance of sputter vapor deposited magnesium alloys and the amount of ion bombardment incurred by the alloy during deposition. Argon pressure, the distance between the source and the substrate, and alloy morphology play important roles in determining the ability of the alloy to develop a passive film. Thermal effects, both during and after alloy deposition, alter the stress state of the alloys, precipitation of second phases, and the mechanical stability of the passive film. An optimal thermal treatment has been developed in order to maximize the corrosion resistance of the magnesium-yttrium-titanium alloys. The significance of the results includes the acquisition of electrochemical data for these novel materials, as well as expanding the utilization of magnesium alloys by the improvement in their corrosion resistance. The magnesium alloys developed in this work are more corrosion resistant than any commercial magnesium alloy. Structural components comprised of these alloys would therefore exhibit unprecedented corrosion performance. Coatings of these alloys on magnesium components would provide a corrosion resistant yet galvanically-compatible coating. The broad impact of these contributions is that these new low-density, corrosion resistant magnesium alloys can be used to produce engineering components for vehicles that have greater acceleration, longer range, heavier payloads, lower life cycle costs, and longer inspection intervals.

  7. Corrosion behavior of Ti-39Nb alloy for dentistry.

    PubMed

    Fojt, Jaroslav; Joska, Ludek; Malek, Jaroslav; Sefl, Vaclav

    2015-11-01

    To increase an orthopedic implant's lifetime, researchers are now concerned on the development of new titanium alloys with suitable mechanical properties (low elastic modulus-high fatigue strength), corrosion resistance and good workability. Corrosion resistance of the newly developed titanium alloys should be comparable with that of pure titanium. The effect of medical preparations containing fluoride ions represents a specific problem related to the use of titanium based materials in dentistry. The aim of this study was to determine the corrosion behavior of β titanium alloy Ti-39Nb in physiological saline solution and in physiological solution containing fluoride ions. Corrosion behavior was studied using standard electrochemical techniques and X-ray photoelectron spectroscopy. It was found that corrosion properties of the studied alloy were comparable with the properties of titanium grade 2. The passive layer was based on the oxides of titanium and niobium in several oxidation states. Alloying with niobium, which was the important part of the alloy passive layer, resulted in no significant changes of corrosion behavior. In the presence of fluoride ions, the corrosion resistance was higher than the resistance of titanium. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Development of corrosion resistant heat exchangers for flue gas desulfurization

    NASA Astrophysics Data System (ADS)

    Ernst, E.; Lorentz, R.

    1984-12-01

    A glass lining as protection against corrosion in flue gas desulfurization plants was developed. Glasses were evaluated under corrosive attack of fluoride-containing acids. The corrosion properties of one-layer and two-layer glass enamels are optimized. Two-layer systems always show better resistance and longer life. The optimized glass linings were tested in a power plant. Manufacturing principles for glass-lined heat exchanger elements are derived. The optimized glasses may be used as protective lining design for heat exchangers or parts of them.

  9. Influence of the pulsed plasma treatment on the corrosion resistance of the low-alloy steel plated by Ni-based alloy

    NASA Astrophysics Data System (ADS)

    Dzhumaev, P.; Yakushin, V.; Kalin, B.; Polsky, V.; Yurlova, M.

    2016-04-01

    This paper presents investigation results of the influence of high temperature pulsed plasma flows (HTPPF) treatment on the corrosion resistance of low-alloy steel 0.2C-Cr-Mn- Ni-Mo cladded by the rapidly quenched nickel-based alloy. A technique that allows obtaining a defect-free clad layer with a good adhesion to the substrate was developed. It is shown that the preliminary treatment of steel samples by nitrogen plasma flows significantly increases their corrosion resistance in the conditions of intergranular corrosion test in a water solution of sulfuric acid. A change of the corrosion mechanism of the clad layer from intergranular to uniform corrosion was observed as a result of sub-microcrystalline structure formation and homogeneous distribution of alloying elements in the plasma treated surface layer thus leading to the significant increase of the corrosion resistance.

  10. Review of recent developments in the field of magnesium corrosion: Recent developments in Mg corrosion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Atrens, Andrej; Song, Guang -Ling; Liu, Ming

    2015-01-07

    This paper provides a review of recent developments in the field of Mg corrosion and puts those into context. This includes considerations of corrosion manifestations, material influences, surface treatment, anodization, coatings, inhibition, biodegradable medical applications, stress corrosion cracking, flammability, corrosion mechanisms for HP Mg, critical evaluation of corrosion mechanisms, and concluding remarks. There has been much research recently, and much research continues in this area. In conclusion, this is expected to produce significantly better, more-corrosion-resistant Mg alloys.

  11. 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

  12. 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.

  13. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO & DOE OCRWM Co-Sponsored Advanced Materials Program

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farmer, J; Haslam, J; Wong, F

    2007-09-19

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoingmore » 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 Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent.« less

  14. Corrosion-protective coatings from electrically conducting polymers

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    In a joint effort between NASA Kennedy and LANL, electrically conductive polymer coatings were developed as corrosion protective coatings for metal surfaces. At NASA Kennedy, the launch environment consist of marine, severe solar, and intermittent high acid and/or elevated temperature conditions. Electrically conductive polymer coatings were developed which impart corrosion resistance to mild steel when exposed to saline and acidic environments. Such coatings also seem to promote corrosion resistance in areas of mild steel where scratches exist in the protective coating. Such coatings appear promising for many commercial applications.

  15. Investigations on the corrosion resistance of metallic bipolar plates (BPP) in proton exchange membrane fuel cells (PEMFC) - understanding the effects of material, coating and manufacturing

    NASA Astrophysics Data System (ADS)

    Dur, Ender

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples meet the 2015 target of the U.S. Department of Energy, surface coating is required. 5- ZrN and CrN coated BPPs exhibited higher corrosion resistance meeting DOE target while TiN coated samples had the lowest corrosion resistance. Higher coating thicknesses improved the corrosion resistance of the BPPs. 6- Process sequence between coating and manufacturing is not significant for hydroforming case (ZrN and CrN) and stamping case (CrN) in terms of the corrosion resistance. In other words, coating the BPP`s substrate material before manufacturing process does not always decrease the corrosion resistance of the BPPs.

  16. Improving the corrosion properties of magnesium AZ31 alloy GTA weld metal using microarc oxidation process

    NASA Astrophysics Data System (ADS)

    Siva Prasad, M.; Ashfaq, M.; Kishore Babu, N.; Sreekanth, A.; Sivaprasad, K.; Muthupandi, V.

    2017-05-01

    In this work, the morphology, phase composition, and corrosion properties of microarc oxidized (MAO) gas tungsten arc (GTA) weldments of AZ31 alloy were investigated. Autogenous gas tungsten arc welds were made as full penetration bead-on-plate welding under the alternating-current mode. A uniform oxide layer was developed on the surface of the specimens with MAO treatment in silicate-based alkaline electrolytes for different oxidation times. The corrosion behavior of the samples was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. The oxide film improved the corrosion resistance substantially compared to the uncoated specimens. The sample coated for 10 min exhibited better corrosion properties. The corrosion resistance of the coatings was concluded to strongly depend on the morphology, whereas the phase composition and thickness were concluded to only slightly affect the corrosion resistance.

  17. Corrosion sensor for monitoring the service condition of chloride-contaminated cement mortar.

    PubMed

    Lu, Shuang; Ba, Heng-Jing

    2010-01-01

    A corrosion sensor for monitoring the corrosion state of cover mortar was developed. The sensor was tested in cement mortar, with and without the addition of chloride to simulate the adverse effects of chloride-contaminated environmental conditions on concrete structures. In brief, a linear polarization resistance method combined with an embeddable reference electrode was utilized to measure the polarization resistance (Rp) using built-in sensor electrodes. Subsequently, electrochemical impedance spectroscopy in the frequency range of 1 kHz to 50 kHz was used to obtain the cement mortar resistance (Rs). The results show that the polarization resistance is related to the chloride content and Rs; ln (Rp) is linearly related to the Rs values in mortar without added chloride. The relationships observed between the Rp of the steel anodes and the resistance of the surrounding cement mortar measured by the corrosion sensor confirms that Rs can indicate the corrosion state of concrete structures.

  18. Corrosion resistance of high-Cr oxide dispersion strengthened ferritic steels in super-critical pressurized water

    NASA Astrophysics Data System (ADS)

    Cho, H. S.; Kimura, A.

    2007-08-01

    The effects of alloying elements, such as Cr and Al, on corrosion resistance in super critical pressurized water (SCPW) have been investigated to develop corrosion resistant oxide-dispersion-strengthened (ODS) steels. Corrosion tests were performed in a SCPW (783 K, 25 MPa) environment. Weight gain was measured after exposure to the SCPW, and then oxide layers were analyzed by low angle X-ray diffraction and SEM microscopy. The weight gains of all high-Cr ODS steels are smaller than an austenitic stainless steel (SUS316L). More uniform and thinner oxidation layers were observed on the ODS steels after corrosion compared to those on 9Cr martensitic steel and SUS316L.

  19. Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications

    NASA Astrophysics Data System (ADS)

    Santa Coloma, P.; Izagirre, U.; Belaustegi, Y.; Jorcin, J. B.; Cano, F. J.; Lapeña, N.

    2015-08-01

    Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath's formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin Probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an oxidation process occurred in the vicinity of the alloy's intermetallic particles. The amount of the Zr deposits at these locations increased with coating's formulations without Ti, which provided the best corrosion resistance. The Cr-free conversion coatings developed in this study for the AA7075-T6 and AA2024-T3 alloys do not meet yet the strict requirements of the aircraft industry. However, they significantly improved the corrosion performance with respect to the bare alloys and could be a good starting point for further studies and optimization.

  20. Controlled ferrite content improves weldability of corrosion-resistant steel

    NASA Technical Reports Server (NTRS)

    Malin, C. O.

    1967-01-01

    Corrosion-resistant steel that adds restrictions on chemical composition to ensure sufficient ferrite content decreases the tendency of CRES to develop cracks during welding. The equations restricting composition are based on the Schaeffler constitution diagram.

  1. High-resistant castable corrosion-resistant nickel alloy for monocrystalline casting by the directional crystallization method

    NASA Astrophysics Data System (ADS)

    Belikov, S. B.; Andrienko, A. G.; Gaiduk, S. V.; Kononov, V. V.; Zamkovoi, V. E.

    2008-01-01

    A high-resistant corrosion-resistant nickel-based alloy has been developed for monocrystalline casting using the directional crystallization method. Its mechanical properties are close to those of aircraft alloys ZhS6K-VI and ZhS6U-VI with an equiaxial structure and ZhS26-VI with an oriented structure. The technology of producing blades for turboprop engines from the new alloy has been developed and tested.

  2. Effect of pH on Semiconducting Property of Passive Film Formed on Ultra-High-Strength Corrosion-Resistant Steel in Sulfuric Acid Solution

    NASA Astrophysics Data System (ADS)

    Sun, Min; Xiao, Kui; Dong, Chaofang; Li, Xiaogang; Zhong, Ping

    2013-10-01

    Because Cr9Ni5MoCo14 is a new ultra-high-strength corrosion-resistant steel, it is important to study its corrosion behavior in sulfuric acid solution, which is used to simulate the aggressive environment. The effect of pH on the electrochemical and semiconducting properties of passive films formed on ultra-high-strength corrosion-resistant steel in sulfuric acid solution was investigated by means of the potentiodynamic polarization technique, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis, and X-ray photoelectron spectroscopy (XPS). The results indicated that Cr9Ni5MoCo14 steel showed a passive state in acid solutions. The corrosion behavior of this Cr9Ni5MoCo14 alloy was influenced by the passive film formed on the surface, including thickness, stability, and partitioning of elements of the passive film. The passive current density decreases with increasing pH, and the corrosion resistance was enhanced by the increasing thickness and depletion of the defects within the passive film. Moreover, an enrichment of chromium (primarily the oxides of Cr) and depletion of iron in the passive film led to improved corrosion resistance. These results can provide a theoretical basis for use of this alloy and further development of ultra-high-strength corrosion-resistant steel in today's society.

  3. Evaluation on the Corrosion of the Three Ni-Cr Alloys with Different Composition

    PubMed Central

    Rao, Srinivasa B.; Chowdhary, Ramesh

    2011-01-01

    Dental casting alloys are widely used in contact with oral tissue for many years now. With the development of new dental alloys over the past 15 years, many questions remain unanswered about their biologic safety. Concepts and current issues concerning the response to the biologic effects of dental casting alloys are presented. In this paper, samples of three commercially available nickel-chrome (Ni-cr) casting alloys (Dentaurum, Bego, Sankin) were taken to assess their corrosion behavior, using potentiodynamic polarization method (electrochemical method) with fusayama artificial saliva as an electrolyte medium to check for their biocompatibility. The parameters for corrosion rate and corrosion resistance were obtained from computer-controlled corrosion schematic instrument, namely, potentiostat through corrosion software (power CV). The results obtained were analyzed by classic Tafel analysis. Statistical analysis was done by Student's t-test and ANOVA test. It was concluded that Dentarum and Bego showed satisfactory corrosive behavior, with exception of Sankin which depicted higher corrosion rate and least resistance to corrosion. Thus, the selection of an alloy should be made on the basis of corrosion resistance and biologic data from dental manufactures. PMID:21461232

  4. Structural design guidelines for concrete bridge decks reinforced with corrosion-resistant reinforcing bars.

    DOT National Transportation Integrated Search

    2014-10-01

    This research program develops and validates structural design guidelines and details for concrete bridge decks with : corrosion-resistant reinforcing (CRR) bars. A two-phase experimental program was conducted where a control test set consistent : wi...

  5. A new, bright and hard aluminum surface produced by anodization

    NASA Astrophysics Data System (ADS)

    Hou, Fengyan; Hu, Bo; Tay, See Leng; Wang, Yuxin; Xiong, Chao; Gao, Wei

    2017-07-01

    Anodized aluminum (Al) and Al alloys have a wide range of applications. However, certain anodized finishings have relatively low hardness, dull appearance and/or poor corrosion resistance, which limited their applications. In this research, Al was first electropolished in a phosphoric acid-based solution, then anodized in a sulfuric acid-based solution under controlled processing parameters. The anodized specimen was then sealed by two-step sealing method. A systematic study including microstructure, surface morphology, hardness and corrosion resistance of these anodized films has been conducted. Results show that the hardness of this new anodized film was increased by a factor of 10 compared with the pure Al metal. Salt spray corrosion testing also demonstrated the greatly improved corrosion resistance. Unlike the traditional hard anodized Al which presents a dull-colored surface, this newly developed anodized Al alloy possesses a very bright and shiny surface with good hardness and corrosion resistance.

  6. Effect of alpha/gamma phase ratio on corrosion behavior of dual-phase stainless steels.

    PubMed

    Lim, Y J; Reyes, M; Thongthammachat, S; Sukchit, K; Panich, M; Oshida, Y

    1999-01-01

    Dual-phase stainless steels have been developed in order to reduce the nickel content, which is potentially responsible to an allergic reaction when these steels are used as medical or dental applications. In this study, two different dual-phase stainless steels (2205 and Z100) were electrochemically tested to evaluate their corrosion resistance in three corrosive solutions (i.e., synthetic saliva, 0.9% NaCl solution, and Ringer solution). Particularly, an attempt was made to correlate the corrosion resistance to a metallographic parameter, which is, in this study, the alpha/gamma phase ratio. It was concluded that (1) type 2205 stainless steel exhibited excellent corrosion resistance in all three corrosion media; however 2205 stainless steel decreases its corrosion resistance by increasing chloride concentration in tested electrolytes from synthetic saliva through 0.9% NaCl solution to Ringer solution. (2) X-ray diffraction analysis indicated that the alpha/gamma phase ratio of 2205 (1.735) was higher than that of Z100 (0.905). As a result, it is suggested that by increasing the alpha/gamma phase ratio the material shows more corrosion-prone behavior when being subjected to a hostile environment containing higher chloride ion concentration.

  7. Corrosion Sensor for Monitoring the Service Condition of Chloride-Contaminated Cement Mortar

    PubMed Central

    Lu, Shuang; Ba, Heng-Jing

    2010-01-01

    A corrosion sensor for monitoring the corrosion state of cover mortar was developed. The sensor was tested in cement mortar, with and without the addition of chloride to simulate the adverse effects of chloride-contaminated environmental conditions on concrete structures. In brief, a linear polarization resistance method combined with an embeddable reference electrode was utilized to measure the polarization resistance (Rp) using built-in sensor electrodes. Subsequently, electrochemical impedance spectroscopy in the frequency range of 1 kHz to 50 kHz was used to obtain the cement mortar resistance (Rs). The results show that the polarization resistance is related to the chloride content and Rs; ln (Rp) is linearly related to the Rs values in mortar without added chloride. The relationships observed between the Rp of the steel anodes and the resistance of the surrounding cement mortar measured by the corrosion sensor confirms that Rs can indicate the corrosion state of concrete structures. PMID:22319347

  8. The corrosion behavior of Fe-Mn-Al weld metals

    NASA Astrophysics Data System (ADS)

    Aidun, Daryush K.

    2001-02-01

    The corrosion resistance of a newly developed iron-base, Fe-Mn-Al austenitic, and duplex weld metal has been examined in the NACE solution consisting of 5 wt.% NaCl, 0.5 wt.% acetic acid, and the balance distilled water. The electrochemical techniques such as potentiodynamic polarization, Tafel plots, linear polarization, cyclic polarization, and open-circuit potential versus time were employed. The Fe-Mn-Al weld metals did not passivate and exhibited high corrosion rates. Fe-Cr-Ni (310 and 316) weld and base metals were also examined in the NACE solution at room temperature. The 310 and 316 base metals were more resistant to corrosion than the as-welded 310 and 316 weld metals. Postweld heat treatment (PWHT) improved the corrosion performance of the Fe-Mn-Al weld metals. The corrosion resistance of Fe-Mn-Al weld metals after PWHT was still inferior to that of the 310 and 316 weld and base metals.

  9. 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.

  10. Improvement of corrosion resistance of low-alloy steels by resurfacing using multifunction cavitation in water

    NASA Astrophysics Data System (ADS)

    Ijiri, Masataka; Yoshimura, Toshihiko

    2018-02-01

    Low-alloy steels are based on carbon steel in combination with several percent or less (in many cases, 1 mass%) alloying elements, and they offer improved resistance to corrosion at a cost slightly higher than that of carbon steel. However, these materials do not exhibit the same corrosion resistance as stainless steel. The authors have previously developed a novel multifunction cavitation (MFC) technique, which combines ultrasonic cavitation with water jet cavitation. In this study, MFC was used to modify the surface of Cr-Mo steel (SCM435) and Ni-Cr-Mo steel (SNCM630). MFC was found to improve the residual stress value of the material as the result of surface modification while also imparting high strength and superior corrosion resistance.

  11. Research and development of weathering resistant bridge steel of Shougang

    NASA Astrophysics Data System (ADS)

    Yang, Yongda; Wang, Yanfeng; Huang, Leqing; Di, Guobiao; Ma, Changwen; Ma, Qingshen

    2017-09-01

    To introduce the composition design and mechanical properties and microstructure of the weathering bridge steel which would be used for bridge of Guanting reservoir. We adopt cyclic immersion corrosion test to study corrosion resistance difference of weathering bridge steel and common bridge steel. At the same corrosion time, the weight loss and corrosion rate of weathering bridge steel are lower than the common bridge steel's. Testing phase composition of rust layer by X-ray diffraction, two kinds of test steel's rust layer is mainly composed of Goethite and Fe3O4 and Fe2O3. At the same corrosion time, the percentage composition of goethite in rust layer of weathering bridge steel are significantly higher than common bridge steel's, the higher goethite content is, the compacter rust layer structure is. The compact rust layer would prevent the water and air passing the rust layer, and then preventing the further corrosion reaction, improving the corrosion resistance performance of weathering bridge steel.

  12. Development of New Type Seawater Resistant Steel and the Research of Its Structure and Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Yin, Baoliang; Yin, Shaojiang; Liu, Zhiyong; Wang, Yunge; Yu, Hao; Li, Haixu; Zhou, Tao

    This paper investigated two kinds of corrosion resistant low alloy steels depending on the environment of the North China see (Steel S) and South China sea (Steel N), respectively. The mechanical and corrosion properties of the two steels were analyzed in this paper. Tin was added into both steels to improve the corrosion resistance. Structure and mechanical properties of the two steels were detected, and the results revealed that the microstructures of both steels were ferrite and little divorced pearlite. The yield strength and impact toughness at -40°C of the steel S are 423MPa and 98 J, respectively. The yield strength and impact toughness at -40°C of the steel N are 437 MPa and 70 J, respectively. The properties mentioned above met or even exceeded the requirement (yield strength 355 MPa, toughness 34 J) in these areas. The corrosion resistant properties of the two steels were also investigated via the means of immersion test and electrochemical experiment. The immersion test indicated that the corrosion rate of steel S and steel N was 0.00938 mg/h·cm2 and 0.00838 mg/h·cm2, respectively, when completely immersed for 168 hours, and the corrosion rate was much lower than that of E36. The Electrochemical experiments showed that the corrosion potential (Ecorr) of both steels was higher in contrast to E36, which indicated a lower corrosion trend.

  13. Applications in the Nuclear Industry for Thermal Spray Amorphous Metal and Ceramic Coatings

    NASA Astrophysics Data System (ADS)

    Blink, J.; Farmer, J.; Choi, J.; Saw, C.

    2009-06-01

    Amorphous metal and ceramic thermal spray coatings have been developed with excellent corrosion resistance and neutron absorption. These coatings, with further development, could be cost-effective options to enhance the corrosion resistance of drip shields and waste packages, and limit nuclear criticality in canisters for the transportation, aging, and disposal of spent nuclear fuel. Iron-based amorphous metal formulations with chromium, molybdenum, and tungsten have shown the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials and their stability at high neutron doses enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for waste package and drip shield applications, although the boron-containing amorphous metals are still favored for criticality control applications. These amorphous metal and ceramic materials have been produced as gas-atomized powders and applied as near full density, nonporous coatings with the high-velocity oxy-fuel process. This article summarizes the performance of these coatings as corrosion-resistant barriers and as neutron absorbers. This article also presents a simple cost model to quantify the economic benefits possible with these new materials.

  14. Superhydrophobic powder additives to enhance chemical agent resistant coating systems for military equipment for the U.S. Marine Corps (USMC) Corrosion Prevention and Control (CPAC) Program

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pawel, Steven J.; Armstrong, Beth L.; Haynes, James A.

    The primary goal of the CPAC program at ORNL was to explore the feasibility of introducing various silica-based superhydrophobic (SH) powder additives as a way to improve the corrosion resistance of US Department of Defense (DOD) military-grade chemical agent resistant coating (CARC) systems. ORNL had previously developed and patented several SH technologies of interest to the USMC, and one of the objectives of this program was to identify methods to incorporate these technologies into the USMC’s corrosion-resistance strategy. This report discusses findings of the CPAC and their application.

  15. The effect of vacuum annealing on corrosion resistance of titanium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chikanov, V.N.; Peshkov, V.V.; Kireev, L.S.

    1994-09-01

    The effect of annealing on the corrosion resistance of OT4-1 sheet titanium in 25% HCl under various air pressures and self-evacuating conditions has been investigated. From the kinetic corrosion curves it follows that the least corrosion resistance of titanium is observed after vacuum annealing. Even low residual air pressure in a chamber improves corrosion resistance. The corrosion resistance of titanium decreases with vacuum-annealing time.

  16. Corrosion-resistant metal surfaces

    DOEpatents

    Sugama, Toshifumi [Wading River, NY

    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.

  17. Replacement of chromates in paints and corrosion protection systems [Stage 1

    DOT National Transportation Integrated Search

    2004-05-01

    This technical report presents the first stage results of a multi-year project to develop chromate-free paints and corrosion protection systems. Chromate coatings and chromate-containing paints are very effective in providing corrosion resistance and...

  18. The Corrosion Behavior of Ni3(Si,Nb) Alloys in Boiling 70 wt.% Sulfuric Acid

    NASA Astrophysics Data System (ADS)

    Hsu, Jen-Hsien; Larson, Christopher M.; Newkirk, Joseph W.; Brow, Richard K.; Zhang, San-Hong

    2016-02-01

    Corrosion-resistant Ni3(Si,Nb) alloys are promising materials of construction for hydrogen-production systems based on the sulfur-iodine thermochemical cycle. In this work, the corrosion rates of three different Ni3(Si,Nb) alloys were measured in boiling 70 wt.% sulfuric acid and a three-stage corrosion mechanism was identified, based on the composition and morphology of surface scale that developed. The α(Ni) + β(Ni3Si) eutectic constituent of the alloy microstructure was selectively attacked by acid and, when present, is detrimental to corrosion resistance. The G-phase (Ni16Si17Nb6) is more passive than the β-matrix and seems to contribute to a lower steady-state corrosion rate.

  19. Corrosion-resistant high-entropy alloys: A review

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shi, Yunzhu; Yang, Bin; Liaw, Peter

    Corrosion destroys more than three percent of the world’s gross domestic product. Therefore, the design of highly corrosion-resistant materials is urgently needed. By breaking the classical alloy-design philosophy, high-entropy alloys (HEAs) possess unique microstructures, which are solid solutions with random arrangements of multiple elements. The particular locally-disordered chemical environment is expected to lead to unique corrosion-resistant properties. In this review, the studies of the corrosion-resistant HEAs during the last decade are summarized. The corrosion-resistant properties of HEAs in various aqueous environments and the corrosion behavior of HEA coatings are presented. The effects of environments, alloying elements, and processing methods onmore » the corrosion resistance are analyzed in detail. Finally, the possible directions of future work regarding the corrosion behavior of HEAs are suggested.« less

  20. Corrosion-resistant high-entropy alloys: A review

    DOE PAGES

    Shi, Yunzhu; Yang, Bin; Liaw, Peter

    2017-02-05

    Corrosion destroys more than three percent of the world’s gross domestic product. Therefore, the design of highly corrosion-resistant materials is urgently needed. By breaking the classical alloy-design philosophy, high-entropy alloys (HEAs) possess unique microstructures, which are solid solutions with random arrangements of multiple elements. The particular locally-disordered chemical environment is expected to lead to unique corrosion-resistant properties. In this review, the studies of the corrosion-resistant HEAs during the last decade are summarized. The corrosion-resistant properties of HEAs in various aqueous environments and the corrosion behavior of HEA coatings are presented. The effects of environments, alloying elements, and processing methods onmore » the corrosion resistance are analyzed in detail. Finally, the possible directions of future work regarding the corrosion behavior of HEAs are suggested.« less

  1. Microstructure Aspects of a Newly Developed, Low Cost, Corrosion-Resistant White Cast Iron

    NASA Astrophysics Data System (ADS)

    Sain, P. K.; Sharma, C. P.; Bhargava, A. K.

    2013-04-01

    The purpose of this work is to study the influence of heat treatment on the corrosion resistance of a newly developed white cast iron, basically suitable for corrosion- and wear-resistant applications, and to attain a microstructure that is most suitable from the corrosion resistance point of view. The composition was selected with an aim to have austenitic matrix both in as-cast and heat-treated conditions. The difference in electrochemical potential between austenite and carbide is less in comparison to that between austenite and graphite. Additionally, graphitic corrosion which is frequently encountered in gray cast irons is absent in white cast irons. These basic facts encouraged us to undertake this work. Optical metallography, hardness testing, X-ray diffractometry, and SEM-EDX techniques were employed to identify the phases present in the as-cast and heat-treated specimens of the investigated alloy and to correlate microstructure with corrosion resistance and hardness. Corrosion testing was carried out in 5 pct NaCl solution (approximate chloride content of sea water) using the weight loss method. In the investigated alloy, austenite was retained the in as-cast and heat-treated conditions. The same was confirmed by X-ray and EDX analysis. The stability and volume fraction of austenite increased with an increase of heat-treated temperature/time with a simultaneous decrease in the volume fraction of massive carbides. The decrease in volume fraction of massive carbides resulted in the availability of alloying elements. These alloying elements, on increasing the heat treatment temperature or increasing the soaking period at certain temperatures, get dissolved in austenite. As a consequence, austenite gets enriched as well as becomes more stable. On cooling from lower soaking period/temperature, enriched austenite decomposes to lesser enriched austenite and to a dispersed phase due to decreasing solid solubility of alloying elements with decreasing temperature. The dispersed second phase precipitated from the austenite adversely influenced corrosion resistance due to unfavorable morphology and enhanced galvanic action. Corrosion rate and hardness were found to decrease with an increase in heat treatment temperatures/soaking periods. It was essentially due to the increase in the volume fraction and stability of the austenitic matrix and favorable morphology of the second phase (carbides). The corrosion resistance of the investigated alloy, heat treated at 1223 K (950 °C) for 8 hours, was comparable to that of Ni-Resist iron. Thus, a microstructure comprising austenite and nearly spherical and finer carbides is the most appropriate from a corrosion point of view. Fortunately, the literature reveals that the same microstructure is also well suited from a wear point of view. It confirms that this investigated alloy will be suitable for corrosive-wear applications.

  2. Corrosion-Resistant Ti- xNb- xZr Alloys for Nitric Acid Applications in Spent Nuclear Fuel Reprocessing Plants

    NASA Astrophysics Data System (ADS)

    Manivasagam, Geetha; Anbarasan, V.; Kamachi Mudali, U.; Raj, Baldev

    2011-09-01

    This article reports the development, microstructure, and corrosion behavior of two new alloys such as Ti-4Nb-4Zr and Ti-2Nb-2Zr in boiling nitric acid environment. The corrosion test was carried out in the liquid, vapor, and condensate phases of 11.5 M nitric acid, and the potentiodynamic anodic polarization studies were performed at room temperature for both alloys. The samples subjected to three-phase corrosion testing were characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX). As Ti-2Nb-2Zr alloy exhibited inferior corrosion behavior in comparison to Ti-4Nb-4Zr in all three phases, weldability and heat treatment studies were carried out only on Ti-4Nb-4Zr alloy. The weldability of the new alloy was evaluated using tungsten inert gas (TIG) welding processes, and the welded specimen was thereafter tested for its corrosion behavior in all three phases. The results of the present investigation revealed that the newly developed near alpha Ti-4Nb-4Zr alloy possessed superior corrosion resistance in all three phases and excellent weldability compared to conventional alloys used for nitric acid application in spent nuclear reprocessing plants. Further, the corrosion resistance of the beta heat-treated Ti-4Nb-4Zr alloy was superior when compared to the sample heat treated in the alpha + beta phase.

  3. Replacement of chromates in paints and corrosion protection systems [Stage 2

    DOT National Transportation Integrated Search

    2004-05-01

    This technical report presents the second stage results of a multi-year project to develop chromate-free paints and corrosion protection systems. Chromate-containing coatings and paints are very effective in providing corrosion resistance and are wid...

  4. DOE-DARPA High-Performance Corrosion-Resistant Materials (HPCRM), Annual HPCRM Team Meeting & Technical Review

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farmer, J; Brown, B; Bayles, B

    The overall goal is to develop high-performance corrosion-resistant iron-based amorphous-metal coatings for prolonged trouble-free use in very aggressive environments: seawater & hot geothermal brines. The specific technical objectives are: (1) Synthesize Fe-based amorphous-metal coating with corrosion resistance comparable/superior to Ni-based Alloy C-22; (2) Establish processing parameter windows for applying and controlling coating attributes (porosity, density, bonding); (3) Assess possible cost savings through substitution of Fe-based material for more expensive Ni-based Alloy C-22; (4) Demonstrate practical fabrication processes; (5) Produce quality materials and data with complete traceability for nuclear applications; and (6) Develop, validate and calibrate computational models to enable lifemore » prediction and process design.« less

  5. Corrosion initiation and propagation behavior of corrosion resistant concrete reinforcing materials

    NASA Astrophysics Data System (ADS)

    Hurley, Michael F.

    The life of a concrete structure exposed to deicing compounds or seawater is often limited by chloride induced corrosion of the steel reinforcement. In this study, the key material attributes that affect the corrosion initiation and propagation periods were studied. These included material composition, surface condition, ageing time, propagation behavior during active corrosion, morphology of attack, and type of corrosion products generated by each rebar material. The threshold chloride concentrations for solid 316LN stainless steel, 316L stainless steel clad over carbon steel, 2101 LDX, MMFX-2, and carbon steel rebar were investigated using electrochemical techniques in saturated calcium hydroxide solutions. Surface preparation, test method, duration of period exposed to a passivating condition prior to introduction of chloride, and presence of cladding defects all affected the threshold chloride concentration obtained. A model was implemented to predict the extension of time until corrosion initiation would be expected. 8 years was the predicted time to corrosion initiation for carbon steel. However, model results confirmed that use of 316LN may increase the time until onset of corrosion to 100 years or more. To assess the potential benefits afforded by new corrosion resistant rebar alloys from a corrosion resistance standpoint the corrosion propagation behavior and other factors that might affect the risk of corrosion-induced concrete cracking must also be considered. Radial pit growth was found to be ohmically controlled but repassivation occurred more readily at high potentials in the case of 316LN and 2101 stainless steels. The discovery of ohmically controlled propagation enabled transformation of propagation rates from simulated concrete pore solution to less conductive concrete by accounting for resistance changes in the surrounding medium. The corrosion propagation behavior as well as the morphology of attack directly affects the propensity for concrete cracking. Experimental results were used in conjunction with an existing model to predict the time until concrete cracking occurs for new rebar materials. The results suggest that corrosion resistant materials offer a significant extension to the corrosion propagation stage over carbon steel, even in very aggressive conditions because small, localized anodes develop when initiated.

  6. Degradation of graphene coated copper in simulated proton exchange membrane fuel cell environment: Electrochemical impedance spectroscopy study

    NASA Astrophysics Data System (ADS)

    Ren, Y. J.; Anisur, M. R.; Qiu, W.; He, J. J.; Al-Saadi, S.; Singh Raman, R. K.

    2017-09-01

    Metallic materials are most suitable for bipolar plates of proton exchange membrane fuel cell (PEMFC) because they possess the required mechanical strength, durability, gas impermeability, acceptable cost and are suitable for mass production. However, metallic bipolar plates are prone to corrosion or they can passivate under PEMFC environment and interrupt the fuel cell operation. Therefore, it is highly attractive to develop corrosion resistance coating that is also highly conductive. Graphene fits these criteria. Graphene coating is developed on copper by chemical vapor deposition (CVD) with an aim to improving corrosion resistance of copper under PEMFC condition. The Raman Spectroscopy shows the graphene coating to be multilayered. The electrochemical degradation of graphene coated copper is investigated by electrochemical impedance spectroscopy (EIS) in 0.5 M H2SO4 solution at room temperature. After exposure to the electrolyte for up to 720 h, the charge transfer resistance (Rt) of the graphene coated copper is ∼3 times greater than that of the bare copper, indicating graphene coatings could improve the corrosion resistance of copper bipolar plates.

  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. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    NASA Astrophysics Data System (ADS)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  9. Corrosion Performance of New Generation Aluminum-Lithium Alloys for Aerospace Applications

    NASA Astrophysics Data System (ADS)

    Moran, James P.; Bovard, Francine S.; Chrzan, James D.; Vandenburgh, Peter

    Over the past several years, a new generation of aluminum-lithium alloys has been developed. These alloys are characterized by excellent strength, low density, and high modulus of elasticity and are therefore of interest for lightweight structural materials applications particularly for construction of current and future aircraft. These new alloys have also demonstrated significant improvements in corrosion resistance when compared with the legacy and incumbent alloys. This paper documents the superior corrosion resistance of the current commercial tempers of these materials and also discusses the corrosion performance as a function of the degree of artificial aging. Results from laboratory corrosion tests are compared with results from exposures in a seacoast atmosphere to assess the predictive capability of the laboratory tests. The correlations that have been developed between the laboratory tests and the seacoast exposures provide confidence that a set of available methods can provide an accurate assessment of the corrosion performance of this new generation of alloys.

  10. [Corrosion resistant properties of different anodized microtopographies on titanium surfaces].

    PubMed

    Fangjun, Huo; Li, Xie; Xingye, Tong; Yueting, Wang; Weihua, Guo; Weidong, Tian

    2015-12-01

    To investigate the corrosion resistant properties of titanium samples prepared by anodic oxidation with different surface morphologies. Pure titanium substrates were treated by anodic oxidation to obtain porous titanium films in micron, submicron, and micron-submicron scales. The surface morphologies, coating cross-sectional morphologies, crystalline structures, and surface roughness of these samples were characterized. Electrochemical technique was used to measure the corrosion potential (Ecorr), current density of corrosion (Icorr), and polarization resistance (Rp) of these samples in a simulated body fluid. Pure titanium could be modified to exhibit different surface morphologies by the anodic oxidation technique. The Tafel curve results showed that the technique can improve the corrosion resistance of pure titanium. Furthermore, the corrosion resistance varied with different surface morphologies. The submicron porous surface sample demonstrated the best corrosion resistance, with maximal Ecorr and Rp and minimal Icorr. Anodic oxidation technology can improve the corrosion resistance of pure titanium in a simulated body fluid. The submicron porous surface sample exhibited the best corrosion resistance because of its small surface area and thick barrier layer.

  11. Hydrogen-Resistant Fe/Ni/Cr-Base Superalloy

    NASA Technical Reports Server (NTRS)

    Bhat, Biliyar N.; Chen, Po-Shou; Panda, Binayak

    1994-01-01

    Strong Fe/Ni/Cr-base hydrogen- and corrosion-resistant alloy developed. Superalloy exhibits high strength and exceptional resistance to embrittlement by hydrogen. Contains two-phase microstructure consisting of conductivity precipitated phase in conductivity matrix phase. Produced in wrought, weldable form and as castings, alloy maintains high ductility and strength in air and hydrogen. Strength exceeds previously known Fe/Cr/Ni hydrogen-, oxidation-, and corrosion-resistant alloys. Provides higher strength-to-weight ratios for lower weight in applications as storage vessels and pipes that must contain hydrogen.

  12. 46 CFR 163.002-11 - Materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... hoist must be a corrosion-resistant wire rope other than galvanized wire rope. (c) Corrosion-resistant materials. Materials of a pilot hoist that are not in watertight enclosures must be— (1) Corrosion-resistant or must be treated to be corrosion-resistant; and (2) Galvanically compatible with each other...

  13. 46 CFR 163.002-11 - Materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... hoist must be a corrosion-resistant wire rope other than galvanized wire rope. (c) Corrosion-resistant materials. Materials of a pilot hoist that are not in watertight enclosures must be— (1) Corrosion-resistant or must be treated to be corrosion-resistant; and (2) Galvanically compatible with each other...

  14. 46 CFR 163.002-11 - Materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... hoist must be a corrosion-resistant wire rope other than galvanized wire rope. (c) Corrosion-resistant materials. Materials of a pilot hoist that are not in watertight enclosures must be— (1) Corrosion-resistant or must be treated to be corrosion-resistant; and (2) Galvanically compatible with each other...

  15. 75 FR 13490 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-22

    ... DEPARTMENT OF COMMERCE International Trade Administration (A-580-816) Certain Corrosion-Resistant... results of the antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat...

  16. 46 CFR 162.017-3 - Materials, construction, and workmanship.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... serviceability. (b) Bodies of pressure-vacuum relief valves must be made of bronze or such corrosion-resistant..., and seats shall be made of bronze or such corrosion-resistant material as may be approved by the... springs shall be made of corrosion-resistant material. Springs plated with corrosion-resistant material...

  17. 76 FR 15291 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-21

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant... results of the antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat...

  18. Effect of carbide precipitation on the corrosion behavior of Inconel alloy 690

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sarver, J.M.; Crum, J.R.; Mankins, W.L.

    1987-01-01

    Intergranular carbide precipitation reactions have been shown to affect the stress corrosion cracking (SCC) resistance of nickel-chromium-iron alloys in environments relative to nuclear steam generators. Carbon solubility curves, time-temperature-sensitization plots and other carbide precipitation data are presented for alloy 690 as an aid in developing heat treatments for improved SCC resistance.

  19. Corrosion-resistant, electrically-conductive plate for use in a fuel cell stack

    DOEpatents

    Carter, J David [Bolingbrook, IL; Mawdsley, Jennifer R [Woodridge, IL; Niyogi, Suhas [Woodridge, IL; Wang, Xiaoping [Naperville, IL; Cruse, Terry [Lisle, IL; Santos, Lilia [Lombard, IL

    2010-04-20

    A corrosion resistant, electrically-conductive, durable plate at least partially coated with an anchor coating and a corrosion resistant coating. The corrosion resistant coating made of at least a polymer and a plurality of corrosion resistant particles each having a surface area between about 1-20 m.sup.2/g and a diameter less than about 10 microns. Preferably, the plate is used as a bipolar plate in a proton exchange membrane (PEMFC) fuel cell stack.

  20. High temperature gradient cobalt based clad developed using microwave hybrid heating

    NASA Astrophysics Data System (ADS)

    Prasad, C. Durga; Joladarashi, Sharnappa; Ramesh, M. R.; Sarkar, Anunoy

    2018-04-01

    The development of cobalt based cladding on a titanium substrate using microwave cladding technique is benchmark in coating area. The developed cladding would serve the function of a corrosion resistant coating under high temperatures. Clads of thickness 500 µm have been developed by microwave hybrid heating. A microwave furnace of 2.45GHz frequency was used at a 900W power level for processing. Impact of processing time on melting and adhesion of clad has been discussed. The study also extended to static thermal analysis of simple parts with cladding using commercial Finite Element analysis (FEA) software. A comparative study is explored between four variants of the clad being developed. The analysis has been conducted using a square sample. Similar temperature gradient is also shown for a proposed multi-layer coating, which includes a thermal barrier coating yttria stabilized zirconia (YSZ) on top of the corrosion resistant clad. The YSZ coating would protect the corrosion resistant cladding and substrate from high temperatures.

  1. 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.

  2. Corrosion resistance of steel materials in LiCl-KCl melts

    NASA Astrophysics Data System (ADS)

    Wang, Le; Li, Bing; Shen, Miao; Li, Shi-yan; Yu, Jian-guo

    2012-10-01

    The corrosion behaviors of 304SS, 316LSS, and Q235A in LiCl-KCl melts were investigated at 450°C by Tafel curves and electrochemical impedance spectroscopy (EIS). 316LSS shows the best corrosion resistance behaviors among the three materials, including the most positive corrosion potential and the smallest corrosion current from the Tafel curves and the largest electron transfer resistance from the Nyquist plots. The results are in good agreement with the weight losses in the static corrosion experiments for 45 h. This may be attributed to the better corrosion resistance of Mo and Ni existing as alloy elements in 316LSS, which exhibit the lower corrosion current densities and more positive corrosion potentials than 316LSS in the same melts.

  3. Corrosion Performance of Inconel 625 in High Sulphate Content

    NASA Astrophysics Data System (ADS)

    Ismail, Azzura

    2016-05-01

    Inconel 625 (UNS N06625) is a type of nickel-chromium-molybdenum alloy with excellent corrosion resistance in a wide range of corrosive media, being especially resistant to pitting and crevice corrosion. However, in aggressive environment, Inconel 625 will suffer corrosion attack like other metals. This research compared the corrosion performance of Inconel 625 when exposed to higher sulphate content compared to real seawater. The results reveal that Inconel 625 is excellent in resist the corrosion attack in seawater. However, at increasing temperature, the corrosion resistance of this metal decrease. The performance is same in seawater with high sulphate content at increasing temperature. It can be concluded that sulphate promote perforation on Inconel 625 and become aggressive agents that accelerate the corrosion attack.

  4. 77 FR 24221 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-23

    ...)] Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission Determinations... countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead...

  5. 46 CFR 162.017-3 - Materials, construction, and workmanship.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... corrosion-resistant wire mesh with a 1/2-inch corrosion-resistant separator on a single screen of 30×30 corrosion-resistant wire mesh shall be fitted on all openings to atmosphere. The net free area through the... bronze or such corrosion-resistant material as may be approved by the Commanding Officer, USCG Marine...

  6. 46 CFR 162.017-3 - Materials, construction, and workmanship.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... corrosion-resistant wire mesh with a 1/2-inch corrosion-resistant separator on a single screen of 30 × 30 corrosion-resistant wire mesh shall be fitted on all openings to atmosphere. The net free area through the... bronze or such corrosion-resistant material as may be approved by the Commanding Officer, USCG Marine...

  7. 46 CFR 162.017-3 - Materials, construction, and workmanship.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... corrosion-resistant wire mesh with a 1/2-inch corrosion-resistant separator on a single screen of 30 × 30 corrosion-resistant wire mesh shall be fitted on all openings to atmosphere. The net free area through the... bronze or such corrosion-resistant material as may be approved by the Commanding Officer, USCG Marine...

  8. 78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-11

    ...)] Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea On the basis of the record... revocation of the countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion-resistant carbon steel flat products from Germany and Korea...

  9. 76 FR 3613 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-20

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon... corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea) for the period of review (POR) January 1, 2008, through December 31, 2008. See Corrosion-Resistant Carbon Steel Flat...

  10. 78 FR 19210 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    .... Scope of the Order Products covered by this order are certain corrosion-resistant carbon steel flat... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon... countervailing duty (CVD) order on corrosion-resistant carbon steel flat products from the Republic of Korea for...

  11. Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

    NASA Astrophysics Data System (ADS)

    Tang, Fujian

    This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

  12. Methodology for assessing the probability of corrosion in concrete structures on the basis of half-cell potential and concrete resistivity measurements.

    PubMed

    Sadowski, Lukasz

    2013-01-01

    In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. Potential E corr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

  13. Properties and durability of the passive films on a nickel-chromium-molybdenum alloy and an iron-based bulk metallic glass

    NASA Astrophysics Data System (ADS)

    Pharkya, Pallavi

    Alloy 22, a Ni-Cr-Mo-W alloy, and SAM1651, an Fe-Cr-Mo-B-Y-C bulk metallic glass are highly corrosion-resistant alloys. The high corrosion resistance of these alloys is due to the formation of tenacious oxide films on their surfaces. This study examines the reformation behavior of the passive films as a function of the corrosion resistance of the alloys and the corrosivity of the environment. The main tasks of this study were (i) to determine the chemical durability of passive films on these highly corrosion-resistant alloys in aggressive environments, (ii) to investigate the durability after mechanically damaging the passive films either locally or over the entire surface area and to study the reformation kinetics, (iii) to compare the durability of the passive films of the aforementioned highly corrosion resistant alloys with an alloy of intermediate corrosion resistance, AL6XN, and an alloy of less corrosion resistance, 316L SS, (iv) to examine the evolution of the electronic properties of the passive films on alloy 22 and SAM1651 under different environmental conditions such as concentrated chloride solution, acidic solution, temperature, potential and oxyanions, and (v) to develop an understanding of the relationship between the passive films' composition, electronic and electrochemical properties and the performance. A combination of techniques was utilized to meet the above mentioned objectives. Cyclic potentiodynamic polarization (CPP) was used to determine the electrochemical parameters such as freely corroding, breakdown and repassivation potentials. Electrochemical impedance spectroscopy (EIS) was used to determine the electronic properties such as impedance, thickness and capacitance of the passive films. Mott-Schottky (M-S) analysis was used to determine the type and the density of the defects in the passive films. The mechanical durability and reformation kinetics of the passive films was investigated using a scratch-repassivation method. The quality and the protectiveness of the reformed passive films after scribing were examined using EIS, M-S analysis, and AES. The results show that the passive films on alloy 22 and SAM1651 possess high chemical and mechanical durability. The reformed passive films acquired the same electronic and elemental properties as the passive films which were undamaged. The passive films on SAM1651 and alloy 22 showed better corrosion resistance and durability than did the passive films on AL6XN and 316L SS. The results also showed that the passive film behavior depends on the inherent corrosion resistance of an alloy and the corrosivity of the environment. The inherent corrosion resistance depends on the concentration of the passivity-providing elements such as Cr and Mo in the bulk composition of the alloy (and passive film), and the corrosivity of the environment which is influenced by chloride concentration, oxyanions, temperature, pH, and oxidizing potential.

  14. Molten salt corrosion of heat resisting alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wong-Moreno, A.; Salgado, R.I.M.; Martinez, L.

    1995-09-01

    This paper is devoted to the study of the corrosion behavior of eight high chromium alloys exposed to three different oil ash deposits with V/(Na+S) atomic ratios 0.58, 2.05 and 13.43, respectively. The alloys were exposed to ash deposits at 750 and 900 C; in this temperature range some deposit constituents have reached their melting point developing a molten salt corrosion process. The group of alloys tested included four Fe-Cr-Ni steels UNS specifications S304000, S31000, N08810 and N08330; two Fe-Cr alloys, UNS S44600 and alloy MA 956; and two Ni-base alloys, UNS N06333 and UNS N06601. The deposits and themore » exposed surfaces were characterized by chemical analysis, XRD, DTA, SEM and x-ray microanalysis. The oil-ash corrosion resistance of alloys is discussed in terms of the characteristics of corrosion product scales, which are determined by interaction between the alloy and the corrosive environment. All the alloys containing nickel exhibited sulfidation when were exposed at 750 C, but at 900 C only those without aluminum presented sulfidation or sulfidation and oxidation, while the alloys containing aluminum only exhibited internal oxidation. In spite of good resistance to corrosion by oil-ash deposits, 446-type alloy might not be suitable for temperatures higher than 750 C because of embrittlement caused by excessive sigma-phase precipitation. Alloy MA956 showed highest corrosion resistance at 900 C to oil-ash deposits with high vanadium content.« less

  15. Demonstration of Antimicrobial Corrosion-Resisting Interior Coating Systems for Military Facilities in Warm, Humid Locations

    DTIC Science & Technology

    2017-06-01

    ER D C/ CE RL T R- 17 -1 9 DoD Corrosion Prevention and Control Program Demonstration of Antimicrobial Corrosion- Resisting Interior ...Demonstration of Antimicrobial Corrosion- Resisting Interior Coating Systems for Military Facilities in Warm, Humid Locations Final Report on...Under Project F10-AR04, “Application of New Corrosion-Resistant Mold Abatement Technologies for Interior Surfaces of Buildings at Fort Polk, LA” ERDC

  16. Corrosion characteristics of nickel alloys. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Zollars, G. F.

    1979-01-01

    This bibliography cites 118 articles from the international literature concerning corrosion characteristics of nickel alloys. Articles dealing with corrosion resistance, corrosion tests, intergranular corrosion, oxidation resistance, and stress corrosion cracking of nickel alloys are included.

  17. Mechanical properties of low-nickel stainless steel

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1978-01-01

    Demand for improved corrosion-resistant steels, coupled with increased emphasis on conserving strategic metals, has led to development of family of stainless steels in which manganese and nitrogen are substituted for portion of usual nickel content. Advantages are approximately-doubled yield strength in annealed condition, better resistance to stress-corrosion cracking, retention of low magnetic permeability even after severe cold working, excellent strength and ductility at cryogenic temperatures, superior resistance to wear and galling, and excellent high-temperature properties.

  18. Influence of gas-powder laser cladding’s technological parameters on structural characteristics of corrosion-resistant steels’ restored surface layer

    NASA Astrophysics Data System (ADS)

    Krylova, S. E.; Oplesnin, S. P.; Goltyapin, M. I.

    2018-03-01

    The results of the developed industrial technology for surface restoration of corrosion-resistant steels by laser surfacing are presented in the article. A comparative analysis of the microstructure of the welded wear-resistant layer, the fusion zone with the base material and the diffusion zone for different technological surfacing regimes are given. Dyrometric studies and nondestructive testing of the deposited layer for defects were performed

  19. The crevice corrosion of cathodically modified titanium in chloride solutions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lingen, E. van der

    1995-12-01

    The susceptibility of titanium to crevice corrosion in low-pH chloride solutions at elevated temperatures can result in major practical problems. Although Grade 7 titanium is considered the most crevice-corrosion resistant material available for these environments, the price increase of palladium has limited the utilization of this alloy. A cost-effective titanium alloy, containing 0.2% ruthenium by mass, has been developed for use in environments of increased chloride concentration and temperature. The crevice corrosion resistance of the Ti-0.2% Ru alloy has been evaluated and compared with that of ASTM commercially pure Grade 2 titanium, Grade 7 titanium (Ti-0.12 to 0.25% palladium bymore » mass) and Grade 12 titanium (Ti-0.8% Ni-0.3% Mo). The results indicated that the cathodically modified titanium alloys, Ti-0.2% Ru and Grade 7 titanium, showed similar resistance to crevice corrosion attack in all the solutions tested, and that their behavior was significantly better than that of Grade 2 and Grade 12 titanium.« less

  20. Amine quinone polyurethane polymers for improved performance in advanced particulate media

    NASA Astrophysics Data System (ADS)

    Warren, G. W.; Sharma, Rahul; Nikles, D. E.; Hu, Y.; Street, S. C.

    1999-03-01

    The magnetic layer used in commercial, high density, metal particle recording media consists of sub-micron sized Fe particles suspended in a polyurethane polymer binder. New amine-quinone polymers, AQPU15 and AQPU100, have been developed for improving corrosion resistance of the particles. A fundamental study of the nature of the AQ polymer/metal oxide interface and its relationship to corrosion resistance is reported. Electrochemical impedance spectroscopy was used to evaluate corrosion behavior of Fe substrates coated with two different thicknesses of each polymer. The extent of corrosion of Fe particles coated with AQ polymers was also measured via the loss in MS with time of immersion in an acid solution. AQ coated particles showed significant improvement in corrosion resistance. FTIR-RA and XPS data show an interaction between AQM14A, a simple model for a portion of the polymer, and metal (Fe, Cu, Al) surfaces which occurs through the π system of the AQ functional group.

  1. Advanced Cast Aluminum Alloys

    DTIC Science & Technology

    2009-02-01

    This production route has demonstrated that aluminum alloys with yield strengths in excess of 690 MPa with good elongation (reportedly 8%) are...series of aluminum alloys have poor-to-fair general corrosion resistance and poor-to-good stress corrosion cracking resistance. Wrought 2519...aluminum alloy has good strength, good ballistic performance, good stress corrosion cracking resistance but only fair general corrosion resistance

  2. Composite coatings improve engines

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Funatani, K.; Kurosawa, K.

    1994-12-01

    About 40% of the power loss in engine systems is attributed to the adverse effects of friction in reciprocating engine components. Over half of this power loss is caused by friction between pistons, piston rings, and cylinder bores. In addition, engine parts may be attacked by corrosive gasoline substitutes such as liquid propane gas and alcohol/gasoline mixtures. To solve both friction and corrosion problems, Nihon Parkerizing Co. has improved the nickel-phosphorus based ceramic composite (NCC) plating technology that was developed for cylinder bores and pistons by Suzuki Motor Co. in the mid 1970s. Iron and nickel-based composite plating technologies havemore » been investigated since the early 1970s, and a few have been used on small two-stroke motorcycle, outboard marine, snowmobile, and some luxury passenger car engine components. Both nickel- and iron-base plating processes are used on cylinders and pistons because they offer excellent wear and corrosion resistance. Nickel-base films have higher corrosion resistance than those based on iron, and are capable of withstanding the corrosive conditions characteristic of high methanol fuels. Unfortunately, they experience a decrease in hardness as operating temperatures increase. However, NCC coatings with phosphorus additions have high hardness even under severe operating conditions, and hardness increases upon exposure to elevated temperatures. In addition to high hardness and corrosion resistance, NCC coatings provide a low friction coefficient, which contributes to the reduction of friction losses between sliding components. When used in low-quality or alcohol fuels, the corrosion resistance of NCC coatings is far higher than that of Fe-P plating. Additionally, the coatings reduce wall and piston temperature, wear of ring groove and skirt, and carbon deposit formation, and they improve output power and torque. These advantages all contribute to the development of light and efficient engines with better fuel mileage.« less

  3. Flame-Resistant Composite Materials For Structural Members

    NASA Technical Reports Server (NTRS)

    Spears, Richard K.

    1995-01-01

    Matrix-fiber composite materials developed for structural members occasionally exposed to hot, corrosive gases. Integral ceramic fabric surface layer essential for resistance to flames and chemicals. Endures high temperature, impedes flame from penetrating to interior, inhibits diffusion of oxygen to interior where it degrades matrix resin, resists attack by chemicals, helps resist erosion, and provides additional strength. In original intended application, composite members replace steel structural members of rocket-launching structures that deteriorate under combined influences of atmosphere, spilled propellants, and rocket exhaust. Composites also attractive for other applications in which corrosion- and fire-resistant structural members needed.

  4. Chemical passivation as a method of improving the electrochemical corrosion resistance of Co-Cr-based dental alloy.

    PubMed

    Rylska, Dorota; Sokołowski, Grzegorz; Sokołowski, Jerzy; Łukomska-Szymańska, Monika

    2017-01-01

    The purpose of the study was to evaluate corrosion resistance of Wirobond C® alloy after chemical passivation treatment. The alloy surface undergone chemical passivation treatment in four different media. Corrosion studies were carried out by means of electrochemical methods in saline solution. Corrosion effects were determined using SEM. The greatest increase in the alloy polarization resistance was observed for passive layer produced in Na2SO4 solution with graphite. The same layer caused the highest increase in corrosion current. Generally speaking, the alloy passivation in Na2SO4 solution with graphite caused a substantial improvement of the corrosion resistance. The sample after passivation in Na2SO4 solution without graphite, contrary to others, lost its protective properties along with successive anodic polarization cycles. The alloy passivation in Na3PO4 solution with graphite was the only one that caused a decrease in the alloy corrosion properties. The SEM studies of all samples after chemical passivation revealed no pit corrosion - in contrast to the sample without any modification. Every successive polarization cycle in anodic direction of pure Wirobond C® alloy enhances corrosion resistance shifting corrosion potential in the positive direction and decreasing corrosion current value. The chemical passivation in solutions with low pH values decreases susceptibility to electrochemical corrosion of Co-Cr dental alloy. The best protection against corrosion was obtained after chemical passivation of Wirobond C® in Na2SO4 solution with graphite. Passivation with Na2SO4 in solution of high pH does not cause an increase in corrosion resistance of WIROBOND C. Passivation process increases alloy resistance to pit corrosion.

  5. Iron-Based Amorphous Metals: High-Performance Corrosion-Resistant Material Development

    NASA Astrophysics Data System (ADS)

    Farmer, Joseph; Choi, Jor-Shan; Saw, Cheng; Haslam, Jeffrey; Day, Dan; Hailey, Phillip; Lian, Tiangan; Rebak, Raul; Perepezko, John; Payer, Joe; Branagan, Daniel; Beardsley, Brad; D'Amato, Andy; Aprigliano, Lou

    2009-06-01

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was cosponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the U.S. Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition, materials synthesis, thermal stability, corrosion resistance, environmental cracking, mechanical properties, damage tolerance, radiation effects, and important potential applications. Amorphous alloys identified as SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) and SAM1651 (Fe48Mo14Cr15Y2C15B6) have been produced as meltspun ribbons (MSRs), dropcast ingots, and thermal-spray coatings. Chromium (Cr), molybdenum (Mo), and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of MSRs and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently, thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests; good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while the open-circuit corrosion potentials (OCPs) were simultaneously monitored; reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber and suitable for criticality-control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional stainless steel and Ni-based materials, and are proving to have excellent wear properties, sufficient to warrant their use in earth excavation, drilling, and tunnel-boring applications. Large areas have been successfully coated with these materials, with thicknesses of approximately 1 cm. The observed corrosion resistance may enable applications of importance in industries such as oil and gas production, refining, nuclear power generation, shipping, etc.

  6. Study of Corrosion Resistance Improvement by Metallic Coating for Overhead Transmission Line Conductor

    NASA Astrophysics Data System (ADS)

    Isozaki, Masanori; Adachi, Kouichi; Hita, Takanori; Asano, Yuji

    Applying anti-corrosion grease and aluminum clad steel (AC) wires to ACSR has adopted as general methods to prevent overhead transmission line conductors and/or wires from corrosion. However, there are some cases that ineffectiveness of those means are reported on some transmission lines passing through acid atmosphere in the vicinity of a factory exhausting acid smoke. The feature of the corrosion caused by acid atmosphere is to show a higher speed in its progressing as well known. As means against such acid corrosion, application of high purity aluminum, selective removal of inter-metallic compound in aluminum and plastic coating wires has been reported before, and each has both of advantage and disadvantage actually. In the former letter, we reported the new type of anti-corrosion grease that shows an excellent property against acid atmosphere as well as in a salty circumstance. Here presents a new type of anti-corrosion technology of applying high corrosion resistance aluminum alloy or zinc coatings on each component wires of a conductor that we succeed in developing through a serial study of anti-corrosion methods on overhead transmission lines.

  7. Development and Testing of a Linear Polarization Resistance Corrosion Rate Probe for Ductile Iron Pipe (Web Report 4361)

    EPA Science Inventory

    The North American water and wastewater community has hundreds of millions of feet of ductile iron pipe in service. Only a portion of the inventory has any form of external corrosion control. Ductile iron pipe, in certain environments, is subject to external corrosion.Linear Pola...

  8. Tribological and corrosion properties of plasma nitrided and nitrocarburized 42CrMo4 steel

    NASA Astrophysics Data System (ADS)

    Kusmic, D.; Van Thanh, D.

    2017-02-01

    This article deals with tribological and corrosion resistance comparison of plasma nitrided and nitrocarburized 42CrMo4 steel used for breech mechanism in the armament production. Increasing of materials demands (like wear resistance, surface hardness, running-in properties and corrosion resistance) used for armament production and in other industrial application leads in the field of surface treatment. Experimental steel samples were plasma nitrided under different nitriding gas ratio at 500 °C for 15h and nitrocarburized for 45 min at temperature 590°C and consequently post-oxidized for 10 min at 430°C. Individual 42CrMo4 steel samples were subsequently metallographically evaluated and characterized by hardness and microhardness measuring. The wear test “ball on disc” was realized for measuring of adhesive wear and coefficient of friction during unlubricated sliding. NSS corrosion tests were realized for corrosion resistance evaluation and expressed by corroded area and calculated corrosion rate. The corrosion resistance evaluation is by the surface corrosion-free surfaces evaluation supplemented using the laser confocal microscopy. Due to different surface treatment and plasma nitriding conditions, there are wear resistance and corrosion resistance differences evident between the plasma nitrided steel samples as well.

  9. Thin-film sulfuric acid anodizing as a replacement for chromic acid anodizing

    NASA Technical Reports Server (NTRS)

    Kallenborn, K. J.; Emmons, J. R.

    1995-01-01

    Chromic acid has long been used to produce a thin, corrosion resistant (Type I) coating on aluminum. Following anodizing, the hardware was sealed using a sodium dichromate solution. Sealing closes up pores inherent in the anodized coating, thus improving corrosion resistance. The thinness of the brittle coating is desirable from a fatigue standpoint, and chromium was absorbed by the coating during the sealing process, further improving corrosion resistance. Unfortunately, both chromic acid and sodium dichromate contain carcinogenic hexavalent chromium. Sulfuric acid is being considered as a replacement for chromic acid. Sulfuric acid of 10-20 percent concentration has traditionally been used to produce relatively thick (Types II and III) or abrasion resistant (Type III) coatings. A more dilute, that is five weight percent, sulfuric acid anodizing process, which produces a thinner coating than Type II or III, with nickel acetate as the sealant has been developed. The process was evaluated in regard to corrosion resistance, throwing power, fatigue life, and processing variable sensitivity, and shows promise as a replacement for the chromic acid process.

  10. Analysis of Brazing Effect on Hot Corrosion Behavior of a Nickel-Based Aerospace Superalloy

    NASA Astrophysics Data System (ADS)

    Esmaeili, N.; Ojo, O. A.

    2018-06-01

    The effects of brazing and use of composite powder mixture as interlayer material on hot corrosion resistance of brazed IN738 superalloy were studied. Brazing was observed to result in significant reduction in the hot corrosion resistance of the superalloy. However, application of composite powder mixture, which consists of additive superalloy powder, enhanced the hot corrosion resistance of brazed samples. It is also found that although the use of composite powder mixture increased hot corrosion resistance of brazed alloy, if the additive powder completely melts, which is possible during brazing, it can significantly reduce the hot corrosion resistance of the brazed joint. Elemental micro-segregation during solidification of the joint with completely melted powder mixture produces chromium-depleted zones and consequently reduces hot corrosion resistance, since a uniform distribution and adequate chromium concentration are necessary to combat hot corrosion. This has not been previously reported in the literature and it is crucial to the use of composite powder mixture for enhancing the properties of brazed superalloys.

  11. Influence of Zeolite Coating on the Corrosion Resistance of AZ91D Magnesium Alloy

    PubMed Central

    Banerjee, P. Chakraborty; Woo, Ren Ping; Grayson, Sam Matthew; Majumder, Amrita; Raman, R. K. Singh

    2014-01-01

    The protective performance of zeolite coating on AZ91D magnesium alloy was evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in 0.1 M sodium chloride solution (NaCl). Electrical equivalent circuit (EEC) was developed based upon hypothetical corrosion mechanisms and simulated to correspond to the experimental data. The morphology and the chemical nature of the coating were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Post corrosion morphologies of the zeolite coated and the uncoated AZ91D alloy were investigated using SEM. The corrosion resistance of the zeolite coated specimen was at least one order of magnitude higher than the uncoated specimen. PMID:28788178

  12. Influence of Zeolite Coating on the Corrosion Resistance of AZ91D Magnesium Alloy.

    PubMed

    Banerjee, P Chakraborty; Woo, Ren Ping; Grayson, Sam Matthew; Majumder, Amrita; Raman, R K Singh

    2014-08-22

    The protective performance of zeolite coating on AZ91D magnesium alloy was evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in 0.1 M sodium chloride solution (NaCl). Electrical equivalent circuit (EEC) was developed based upon hypothetical corrosion mechanisms and simulated to correspond to the experimental data. The morphology and the chemical nature of the coating were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Post corrosion morphologies of the zeolite coated and the uncoated AZ91D alloy were investigated using SEM. The corrosion resistance of the zeolite coated specimen was at least one order of magnitude higher than the uncoated specimen.

  13. The metallurgy of high temperature alloys

    NASA Technical Reports Server (NTRS)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  14. An electrochemical study of the corrosion behavior of primer coated 2219-T87 aluminum

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Higgins, R. H.

    1985-01-01

    The corrosion behavior for 2219-T87 aluminum coated with various primers, including those used for the external tank and solid rocket boosters of the Space Shuttle Transportation System, were investigated using electrochemical techniques. Corrosion potential time, polarization resistance time, electrical resistance time, and corrosion rate time measurements were all investigated. It was found that electrical resistance time and corrosion rate time measurement were most useful for studying the corrosion behavior of painted aluminum. Electrical resistance time determination give useful information concerning the porosity of paint films, while corrosion rate time curves give important information concerning overall corrosion rates and corrosion mechanisms. In general, the corrosion rate time curves all exhibited at least one peak during the 30 day test period, which was attributed, according to the proposed mechanisms, to the onset of the hydrogen evolution reaction and the beginning of destruction of the protective properties of the paint film.

  15. Determining cyclic corrosion cracking resistance for titanium alloys with allowance for electrochemical conditions at the fatigue corrosion crack tip

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Panasyuk, V.V.; Ratich, L.V.; Petranyuk, I.Ya.

    1994-08-01

    Published data are examined on how various factors affect fatigue crack growth rates. Basic diagrams have been constructed for the cyclic cracking resistance in Ti-6Al-4V and Ti-6Al-2Sn alloys in air, distilled water, and 3.5% NaCl for use in working-life calculations. Appropriate heat treatment can produce two microstructures in a titanium alloy, one of which has the largest cyclic cracking resistance, while in the second, the cracks grow at the lowest rate. The cyclic corrosion cracking resistance for a titanium alloy should be determined in relation to the state of stress and strain and to the electrochemical conditions at the corrosionmore » fatigue crack tip, while the variations in fatigue crack growth rate for a given stress intensity factor in a corrosive medium are due to differing electrochemical conditions at the crack tip during the testing on different specimens. Basic diagrams can be derived for titanium alloys by using a physically sound methodology developed previously for steels, which is based on invariant diagrams for cyclic cracking resistance in air and in the corresponding medium, which can be constructed in relation to extremal working and electrochemical conditions at corrosion-fatigue crack tips.« less

  16. Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

    2017-04-01

    Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

  17. Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

    NASA Astrophysics Data System (ADS)

    Yenilmez, A.; Karakan, M.; Çelik, İ.

    2017-01-01

    Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens' structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

  18. Corrosion resistant PEM fuel cell

    DOEpatents

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

  19. 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.

  20. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. (b... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. ...

  1. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. (b... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. ...

  2. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. (b... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. ...

  3. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. (b... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. ...

  4. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. (b... corrosion-resistant material; or (ii) Protected against and maintained free from injurious corrosion. ...

  5. Development of an Anti-Corrosion Conductive Nano Carbon Coating Layer on Metal Bipolar Plates.

    PubMed

    Yeo, Kiho; Kim, Juyong; Kim, Jongryoul

    2018-09-01

    For automotive applications of polymer electrolyte membrane fuel cells, the enhancement of the corrosion resistance of metal bipolar plates has been a critical issue with regard to the lifespan of fuel cell stacks. In this paper, we present a novel method for increasing the lifespan by means of a conductive carbon coating on bipolar plates. Conductive carbon films were plasma coated onto metal bipolar plates in a vacuum at various temperatures. As a result, 316L stainless plates with a 10-nm-thick carbon coating layer on a 20-nm-thick CrN undercoat layer showed-contact resistance of 10.71 mΩcm2@10 kgf/cm2 and a corrosion current of 0.5 μA/cm2@0.6 V. This thin coating layer with high conductivity and excellent corrosion resistance suggests a new, effective coating method for the mass production of metal bipolar plates.

  6. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kauffman, D.; Gay, R.J.

    The effective passivating corrosion control system discovered and developed by Mr. Richard Gay was successfully tested under severely corrosive conditions: temperature to 250/sup 0/C, 1% NaCl, pH 4.5, with 0.018 M CO/sub 2/ and 0.054 M H/sub 2/S. A hard, corrosion-resistant film was deposited on steel test coupons, and further corrosion was prevented. Potential applications for the system include sour oil and gas wells and gathering systems, geothermal wells and gathering systems, gas processing plants and refineries. Ultimate commercial development will require additional field and laboratory test work.

  7. Effect of Aging Temperature on Corrosion Behavior of Sintered 17-4 PH Stainless Steel in Dilute Sulfuric Acid Solution

    NASA Astrophysics Data System (ADS)

    Szewczyk-Nykiel, Aneta; Kazior, Jan

    2017-07-01

    The general corrosion behavior of sintered 17-4 PH stainless steel processed under different processing conditions in dilute sulfuric acid solution at 25 °C was studied by open-circuit potential measurement and potentiodynamic polarization technique. The corrosion resistance was evaluated based on electrochemical parameters, such as polarization resistance, corrosion potential, corrosion current density as well as corrosion rate. The results showed that the precipitation-hardening treatment could significantly improve the corrosion resistance of the sintered 17-4 PH stainless steel in studied environment. As far as the influence of aging temperature on corrosion behavior of the sintered 17-4 PH stainless steel is concerned, polarization resistance and corrosion rate are reduced with increasing aging temperature from 480 up to 500 °C regardless of the temperature of solution treatment. It can be concluded that the highest corrosion resistance in 0.5 M H2SO4 solution exhibits 17-4 PH after solution treatment at 1040 °C followed by aging at 480 °C.

  8. Hot corrosion behavior of platinum-modified nickel- and cobalt-based alloys and coatings

    NASA Astrophysics Data System (ADS)

    Deodeshmukh, Vinay Prakash

    High temperature degradation by hot corrosion (650-1000°C) and/or oxidation (>1000°C) can severely reduce the longevity of advanced gas turbine engine components. The protection of high-temperature components against hot corrosion or oxidation is typically conferred by the application of either a diffusion or overlay metallic coating that is able to form a continuous, adherent, and slow-growing oxide scale. There are currently no coatings that provide adequate protection to both hot corrosion and oxidation. Indeed, there is a particular need for such protective coatings because many advanced aero, marine, and industrial gas-turbines operate in both hot corrosion and oxidation regimes in their duty cycle. Recent work at Iowa State University (ISU) has showed that a wide range Pt+Hf-modified gamma'-Ni3Al + gamma-Ni alloy compositions form a very adherent and slow-growing Al 2O3 scale. In fact, the results reported suggest that Pt+Hf-modified gamma' + gamma coatings offer a viable superior alternative to beta-NiAl(Pt)-based coatings. The main thrust of this study was to assess and establish optimum target gamma' + gamma coating compositions for extending the service life of high-temperature gas turbine components exposed to hot corrosion and oxidation conditions. Both high temperature hot-corrosion (HTHC-900°C) and low temperature hot-corrosion (LTHC-705°C) behaviors of the Pt+Hf-modified gamma' + gamma alloys were assessed. The salt used to bring about hot corrosion was Na 2SO4. Quite interestingly, it was found that the HTHC resistance of gamma' + gamma alloys improved with up to about 10 at.% Pt addition, but then decreased significantly with increasing Pt content up to 30 at.% (the maximum level studied); however, under LTHC conditions the resistance of gamma' + gamma alloys improved with increasing Pt content up to 30 at.%. To further improve hot corrosion resistance of Pt+Hf-modified gamma' + gamma alloys, the effects of systematic additions of Cr, Si, and Cr+Si were assessed. The effects pre-oxidation treatments were also studied to further improve the hot corrosion resistance. In addition, high-temperature oxidation behavior of various modified of gamma' + gamma alloys was studied in air at 1150°C under both isothermal and cyclic oxidation conditions. Certain modified versions of gamma' + gamma coating composition(s) exhibited excellent resistance to both hot corrosion and oxidation. Finally, the HTHC and LTHC resistance of novel Pt+Hf-modified gamma' + gamma-based diffusion coatings using a pack cementation process developed at ISU were studied and compared with state-of-the-art commercial coatings. It was found that the Pt+Hf-modified gamma' + gamma coating exhibited superior resistance to both types of hot corrosion with the preoxidation treatment; while, only Pt-modified beta exhibited excellent LTHC resistance with no pre-oxidation treatment. This study also involved evaluating the hot corrosion resistance of various commercially available Pt-modified beta-NiAl diffusion aluminides and CoCrAlY-based overlay coatings for marine gas turbine engine components under both HTHC and LTHC conditions. The Al-Pt-rich beta aluminide exhibited improved resistance to both types of hot corrosion compared to the various Ni-rich beta aluminide and CoCrAlY coatings.

  9. Powder-Metallurgical Bearings For Turbopumps

    NASA Technical Reports Server (NTRS)

    Bhat, B. N.; Humphries, T. S.; Thom, R. L.; Moxson, V.; Friedman, G. I.; Dolan, F. J.; Shipley, R. J.

    1993-01-01

    Bearings fabricated by powder metallurgy developed for use in machines subjected to extremes of temperature, rolling-contact cyclic stresses, and oxidizing or otherwise corrosive fluids. Bearings also extend operating lives of other machines in which bearings required to resist extreme thermal, mechanical, and chemical stresses. One alloy exhibiting outstanding properties was MRC-2001. Resistance to fatigue, stress corrosion cracking, and wear found superior to that of 440C stainless steel.

  10. Influence of Surface Pretreatment on the Corrosion Resistance of Cold-Sprayed Nickel Coatings in Acidic Chloride Solution

    NASA Astrophysics Data System (ADS)

    Scendo, Mieczyslaw; Zorawski, Wojciech; Staszewska-Samson, Katarzyna; Makrenek, Medard; Goral, Anna

    2018-03-01

    Corrosion resistance of the cold-sprayed nickel coatings deposited on the Ni surface (substrate) without and with abrasive grit-blasting treatment of the substrate was investigated. The corundum powder with different grain sizes was used. The corrosive environment contained an acidic chloride solution. The mechanism of the corrosion of nickel was suggested and discussed. Corrosion electrochemical parameters were determined by electrochemical methods. The corrosion effect of a nickel coating depends on the grain size used to prepare the substrate. The nickel coating after the medium grit-blasting treatment of the substrate was found to be the most corrosion resistant. However, the smallest resistance on the corrosion effect should be attributed to the nickel coating on the substrate after the coarse grit-blasting treatment.

  11. Electrochemical Corrosion and In Vitro Bioactivity of Nano-Grained Biomedical Ti-20Nb-13Zr Alloy in a Simulated Body Fluid

    PubMed Central

    Kumar, Madhan; Drew, Robin; Al-Aqeeli, Nasser

    2017-01-01

    The bioactivity and the corrosion protection for a novel nano-grained Ti-20Nb-13Zr at % alloy were examined in a simulated body fluid (SBF). The effect of the SPS’s temperature on the corrosion performance was investigated. The phases and microstructural details of the developed alloy were analyzed by XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), and TEM (Transmission Electron Microscope). The electrochemical study was investigated using linear potentiodynamic polarization and electrochemical impedance spectroscopy in a SBF, and the bioactivity was examined by immersing the developed alloy in a SBF for 3, 7, and 14 days. The morphology of the depositions after immersion was examined using SEM. Alloy surface analysis after immersion in the SBF was characterized by XPS (X-ray Photoelectron Spectroscopy). The results of the bioactivity test in SBF revealed the growth of a hydroxyapatite layer on the surface of the alloy. The analysis of XPS showed the formation of protective oxides of TiO2, Ti2O3, ZrO2, Nb2O5, and a Ca3(PO4)2 compound (precursor of hydroxyapatite) deposited on the alloy surface, indicating that the presented alloy can stimulate bone formation. The corrosion resistance increased by increasing the sintering temperature and the highest corrosion resistance was obtained at 1200 °C. The improved corrosion protection was found to be related to the alloy densification. The bioactivity and the corrosion resistance of the developed nanostructured alloy in a SBF renders the nanostructured Ti-20Nb-13Zr alloy a promising candidate as an implant material. PMID:29280956

  12. Study program for encapsulation materials interface for low-cost solar array

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.; Mansfeld, F. B.; Kendig, M.; Leung, C.

    1981-01-01

    The service integrity of the bonded interface in solar cell modules used in solar arrays is addressed. The development of AC impedance as a nondestructive evaluation (NDE) methodology for solar arrays is reported along with development of corrosion models and materials selection criteria for corrosion resistant interfaces.

  13. Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

    PubMed Central

    2013-01-01

    In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. Potential E corr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures. PMID:23766706

  14. A high-specific-strength and corrosion-resistant magnesium alloy

    NASA Astrophysics Data System (ADS)

    Xu, Wanqiang; Birbilis, Nick; Sha, Gang; Wang, Yu; Daniels, John E.; Xiao, Yang; Ferry, Michael

    2015-12-01

    Ultra-lightweight alloys with high strength, ductility and corrosion resistance are desirable for applications in the automotive, aerospace, defence, biomedical, sporting and electronic goods sectors. Ductility and corrosion resistance are generally inversely correlated with strength, making it difficult to optimize all three simultaneously. Here we design an ultralow density (1.4 g cm-3) Mg-Li-based alloy that is strong, ductile, and more corrosion resistant than Mg-based alloys reported so far. The alloy is Li-rich and a solute nanostructure within a body-centred cubic matrix is achieved by a series of extrusion, heat-treatment and rolling processes. Corrosion resistance from the environment is believed to occur by a uniform lithium carbonate film in which surface coverage is much greater than in traditional hexagonal close-packed Mg-based alloys, explaining the superior corrosion resistance of the alloy.

  15. A high-specific-strength and corrosion-resistant magnesium alloy.

    PubMed

    Xu, Wanqiang; Birbilis, Nick; Sha, Gang; Wang, Yu; Daniels, John E; Xiao, Yang; Ferry, Michael

    2015-12-01

    Ultra-lightweight alloys with high strength, ductility and corrosion resistance are desirable for applications in the automotive, aerospace, defence, biomedical, sporting and electronic goods sectors. Ductility and corrosion resistance are generally inversely correlated with strength, making it difficult to optimize all three simultaneously. Here we design an ultralow density (1.4 g cm(-3)) Mg-Li-based alloy that is strong, ductile, and more corrosion resistant than Mg-based alloys reported so far. The alloy is Li-rich and a solute nanostructure within a body-centred cubic matrix is achieved by a series of extrusion, heat-treatment and rolling processes. Corrosion resistance from the environment is believed to occur by a uniform lithium carbonate film in which surface coverage is much greater than in traditional hexagonal close-packed Mg-based alloys, explaining the superior corrosion resistance of the alloy.

  16. The effects of RE and Si on the microstructure and corrosion resistance of Zn-6Al-3Mg hot dip coating

    NASA Astrophysics Data System (ADS)

    Li, Shiwei; Gao, Bo; Yin, Shaohua; Tu, Ganfeng; Zhu, Guanglin; Sun, Shuchen; Zhu, Xiaoping

    2015-12-01

    The effects of Si and RE on the microstructure and corrosion resistance of Zn-6Al-3Mg coating (ZAM) have been investigated. Surface morphology observations of the coating and corrosion products reveal that the additions of Si and rare earth metals (RES) improve the microstructural homogeneity of ZAMSR coating and stability of corrosion products formed on ZAMSR coating. Moreover, only uniform corrosion occurs in ZAMSR coating during the corrosion test, while intergranular corrosion and pitting occur in ZAM. As a result, the corrosion resistance of ZAM coating is improved by the additions of Si and RES.

  17. 77 FR 25141 - Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-428-815, A-580-816] Corrosion...) orders on corrosion-resistant carbon steel flat products (CORE) from Germany and South Korea (Korea..., regarding ``Sunset Reviews of the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel Flat Products...

  18. In vitro investigation of biodegradable polymeric coating for corrosion resistance of Mg-6Zn-Ca alloy in simulated body fluid.

    PubMed

    Gaur, Swati; Singh Raman, R K; Khanna, A S

    2014-09-01

    A silane-based biodegradable coating was developed and investigated to improve corrosion resistance of an Mg-6Zn-Ca magnesium alloy to delay the biodegradation of the alloy in the physiological environment. Conditions were optimized to develop a stable and uniform hydroxide layer on the alloys surface-known to facilitate silane-substrate adhesion. A composite coating of two silanes, namely, diethylphosphatoethyltriethoxysilane (DEPETES) and bis-[3-(triethoxysilyl) propyl] tetrasulfide (BTESPT), was developed, by the sol-gel route. Corrosion resistance of the coated alloy was characterized in a modified-simulated body fluid (m-SBF), using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The silane coating provided significant and durable corrosion resistance. During the course of this, hydrogen evolution and pH variation, if any, were monitored for both bare and coated alloys. The coating morphology was characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) and the cross-linking in the coating was studied using Fourier transform infrared spectroscopy (FTIR). As indicated by X-ray diffraction (XRD) results, an important finding was the presence of hydrated magnesium phosphate on the sample that was subjected to immersion in m-SBF for 216h. Magnesium phosphate is reported to support osteoblast formation and tissue healing. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment.

    PubMed

    Boinovich, Ludmila B; Emelyanenko, Alexandre M; Modestov, Alexander D; Domantovsky, Alexandr G; Emelyanenko, Kirill A

    2015-09-02

    We report a new efficient method for fabricating a superhydrophobic oxidized surface of aluminum alloys with enhanced resistance to pitting corrosion in sodium chloride solutions. The developed coatings are considered very prospective materials for the automotive industry, shipbuilding, aviation, construction, and medicine. The method is based on nanosecond laser treatment of the surface followed by chemisorption of a hydrophobic agent to achieve the superhydrophobic state of the alloy surface. We have shown that the surface texturing used to fabricate multimodal roughness of the surface may be simultaneously used for modifying the physicochemical properties of the thick surface layer of the substrate itself. Electrochemical and wetting experiments demonstrated that the superhydrophobic state of the metal surface inhibits corrosion processes in chloride solutions for a few days. However, during long-term contact of a superhydrophobic coating with a solution, the wetted area of the coating is subjected to corrosion processes due to the formation of defects. In contrast, the combination of an oxide layer with good barrier properties and the superhydrophobic state of the coating provides remarkable corrosion resistance. The mechanisms for enhancing corrosion protective properties are discussed.

  20. A Study of Magnesium-Base Metallic Systems and Development of Principles for Creation of Corrosion-Resistant Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Mukhina, I. Yu.

    2014-11-01

    The effect of 26 alloying elements on the corrosion resistance of high-purity magnesium in a 0.5-n solution of sodium chloride and in a humid atmosphere (0.005 n) is studied. The Mg - Li, Mg - Ag, Mg - Zn, Mg - Cu, Mg - Gd, Mg - Al, Mg - Zr, Mg - Mn and other binary systems, which present interest as a base for commercial or perspective castable magnesium alloys, are studied. The characteristics of corrosion resistance of the binary alloys are analyzed in accordance with the group and period of the Mendeleev's periodic law. The roles of the electrochemical and volume factors and of the factor of the valence of the dissolved element are determined.

  1. Microstructure, Properties and Weldability of Duplex Stainless Steel 2101

    NASA Astrophysics Data System (ADS)

    Ma, Li; Hu, Shengsun; Shen, Junqi

    2017-01-01

    The continuous development of duplex stainless steels (DSSs) is due to their excellent corrosion resistance in aggressive environments and their mechanical strength, which is usually twice of conventional austenitic stainless steels (ASSs). In this paper, a designed lean duplex stainless steel 2101, with the alloy design of reduced nickel content and increased additions of manganese and nitrogen, is studied by being partly compared with typical ASS 304L steels. The microstructure, mechanical properties, impact toughness, corrosion resistance and weldability of the designed DSS 2101 were conducted. The results demonstrated that both 2101 steel and its weldment show excellent mechanical properties, impact toughness and corrosion resistance, so DSS 2101 exhibits good comprehensive properties and can be used to replace 304L in numerous applications.

  2. Corrosion behavior in high heat input welded heat-affected zone of Ni-free high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Moon, Joonoh, E-mail: mjo99@kims.re.kr; Ha, Heon-Young; Lee, Tae-Ho

    2013-08-15

    The pitting corrosion and interphase corrosion behaviors in high heat input welded heat-affected zone (HAZ) of a metastable high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel were explored through electrochemical tests. The HAZs were simulated using Gleeble simulator with high heat input welding condition of 300 kJ/cm and the peak temperature of the HAZs was changed from 1200 °C to 1350 °C, aiming to examine the effect of δ-ferrite formation on corrosion behavior. The electrochemical test results show that both pitting corrosion resistance and interphase corrosion resistance were seriously deteriorated by δ-ferrite formation in the HAZ and their aspects were different with increasingmore » δ-ferrite fraction. The pitting corrosion resistance was decreased by the formation of Cr-depleted zone along δ-ferrite/austenite (γ) interphase resulting from δ-ferrite formation; however it didn't depend on δ-ferrite fraction. The interphase corrosion resistance depends on the total amount of Cr-depleted zone as well as ferrite area and thus continuously decreased with increasing δ-ferrite fraction. The different effects of δ-ferrite fraction on pitting corrosion and interphase corrosion were carefully discussed in terms of alloying elements partitioning in the HAZ based on thermodynamic consideration. - Highlights: • Corrosion behavior in the weld HAZ of high-nitrogen austenitic alloy was studied. • Cr{sub 2}N particle was not precipitated in high heat input welded HAZ of tested alloy. • Pitting corrosion and interphase corrosion show a different behavior. • Pitting corrosion resistance was affected by whether or not δ-ferrite forms. • Interphase corrosion resistance was affected by the total amount of δ-ferrite.« less

  3. Investigation into the Susceptibility of Corrosion Resistant Alloys to Biocorrosion

    DTIC Science & Technology

    1994-06-30

    Fro Bes AvialeC p INVESTIGATION INTO THE SUSCEPTIBILITY OF CORROSION RESISTANT ALLOYS TO BIOCORROSION Dr. Clive R.Clayton Dept.of Materials Science...QUAW jjqMCMD 9 INVESTIGATION INTO THE SUSCEPTIBILTY OF CORROSION RESISTANT ALLOYS TO BIOCORROSION Dr.Clive R.Clayton Dept. of Materials Science & Engg...TITLE (Mmkude Secwty camuf*tigon Investigation into the Susceptibility of Corrosion ’Resistant Alloys to Biocorrosion IL. PERSONAL AUThOR(S) Clive R

  4. Development of Custom 465® Corrosion-Resisting Steel for Landing Gear Applications

    NASA Astrophysics Data System (ADS)

    Daymond, Benjamin T.; Binot, Nicolas; Schmidt, Michael L.; Preston, Steve; Collins, Richard; Shepherd, Alan

    2016-04-01

    Existing high-strength low-alloy steels have been in place on landing gear for many years owing to their superior strength and cost performance. However, there have been major advances in improving the strength of high-performance corrosion-resisting steels. These materials have superior environmental robustness and remove the need for harmful protective coatings such as chromates and cadmium now on the list for removal under REACH legislation. A UK government-funded collaborative project is underway targeting a refined specification Custom 465® precipitation hardened stainless steel to replace the current material on Airbus A320 family aircraft main landing gear, a main fitting component developed by Messier-Bugatti-Dowty. This is a collaborative project between Airbus, Messier-Bugatti-Dowty, and Carpenter Technology Corporation. An extensive series of coupon tests on four production Heats of the material have been conducted, to obtain a full range of mechanical, fatigue, and corrosion properties. Custom 465® is an excellent replacement to the current material, with comparable tensile strength and fracture toughness, better ductility, and very good general corrosion and stress corrosion cracking resistance. Fatigue performance is the only significant area of deficit with respect to incumbent materials, fatigue initiation being often related to carbo-titanium-nitride particles and cleavage zones.

  5. The Weathering of Aluminum Alloy Sheet Materials Used in Aircraft

    NASA Technical Reports Server (NTRS)

    Mutchler, Willard

    1935-01-01

    This report presents the results of an investigation of the corrosion of aluminum alloy sheet materials used in aircraft. It has for its purpose to study the causes of corrosion embrittlement in duralumin-type alloys and the development of methods for its elimination. The report contains results, obtained in an extensive series of weather-exposure tests, which reveal the extent to which the resistance of the materials to corrosion was affected by variable factors in their heat treatment and by the application of various surface protective coatings. The results indicate that the sheet materials are to be regarded as thoroughly reliable, from the standpoint of their permanence in service, provided proper precautions are taken to render them corrosion-resistant.

  6. Effect of ECAP processing on corrosion resistance of AE21 and AE42 magnesium alloys

    NASA Astrophysics Data System (ADS)

    Minárik, P.; Král, R.; Janeček, M.

    2013-09-01

    Corrosion properties of AE21 and AE42 magnesium alloys were investigated in the extruded state and after subsequent 8 passes of Equal Channel Angular Pressing (ECAP) via route Bc, by Electrochemical Impedance Spectroscopy (EIS) in 0.1 M NaCl solution. The resulting microstructure was observed by the Transmission Electron Microscope (TEM) and the Scanning Electron Microscope (SEM). Corrosion layer created after 7 days of immersion was observed by (SEM) in order to explain different evolution of the corrosion resistance after ECAP processing in both alloys. It was found that Al-rich Al11RE3 dispersed particles (present in both alloys) strongly influence the corrosion process and enhance the corrosion resistance. Ultra-fine grained structure was found to reduce the corrosion resistance in AE21. On the other hand, the microstructure of AE42 after ECAP and particularly the better distribution of the alloying elements in the matrix enhance the corrosion resistance when compared to the extruded material.

  7. Development in corrosion resistance by microstructural refinement in Zr-16 SS 304 alloy using suction casting technique

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Das, N., E-mail: nirupamd@barc.gov.in; Sengupta, P.; Abraham, G.

    Highlights: • Grain refinement was made in Zr–16 wt.% SS alloy while prepared by suction casting process. • Distribution of Laves phase, e.g., Zr{sub 2}(Fe, Cr) was raised in suction cast (SC) Zr–16 wt.% SS. • Corrosion resistance was improved in SC alloy compared to that of arc-melt-cast alloy. • Grain refinement in SC alloy assisted for an increase in its corrosion resistance. - Abstract: Zirconium (Zr)-stainless steel (SS) hybrid alloys are being considered as baseline alloys for developing metallic-waste-form (MWF) with the motivation of disposing of Zr and SS base nuclear metallic wastes. Zr–16 wt.% SS, a MWF alloymore » optimized from previous studies, exhibit significant grain refinement and changes in phase assemblages (soft phase: Zr{sub 2}(Fe, Cr)/α-Zr vs. hard phase: Zr{sub 3}(Fe, Ni)) when prepared by suction casting (SC) technique in comparison to arc-cast-melt (AMC) route. Variation in Cr-distribution among different phases are found to be low in suction cast alloy, which along with grain refinement restricted Cr-depletion at the Zr{sub 2}(Fe, Cr)/Zr interfaces, prone to localized attack. Hence, SC alloy, compared to AMC alloy, showed lower current density, higher potential at the breakdown of passivity and higher corrosion potential during polarization experiments (carried out under possible geological repository environments, viz., pH 8, 5 and 1) indicating its superior corrosion resistance.« less

  8. Modern steels for light automobiles (review)

    NASA Astrophysics Data System (ADS)

    Tikhonov, A. K.

    1994-10-01

    The article considers the directions of work at VAZ together with metallurgists of the CIS for creating highly efficient economically-alloyed and microalloyed steels; highly ductile forged steels with improved corrosion resistance coated with zinc and with good stamping, welding, and painting capacity. Steels are created for petrol tanks with aluminum-zinc coatings instead of lead, and new heat and corrosion-resistant steels are developed for automobile exhaust gas systems.

  9. Corrosion Resistant FBG-Based Quasi-Distributed Sensor for Crude Oil Tank Dynamic Temperature Profile Monitoring

    PubMed Central

    da Silva Marques, Rogério; Prado, Adilson Ribeiro; da Costa Antunes, Paulo Fernando; de Brito André, Paulo Sérgio; Ribeiro, Moisés R. N.; Frizera-Neto, Anselmo; Pontes, Maria José

    2015-01-01

    This article presents a corrosion resistant, maneuverable, and intrinsically safe fiber Bragg grating (FBG)-based temperature optical sensor. Temperature monitoring is a critical activity for the oil and gas industry. It typically involves acquiring the desired parameters in a hazardous and corrosive environment. The use of polytetrafluoroethylene (PTFE) was proposed as a means of simultaneously isolating the optical fiber from the corrosive environment and avoiding undesirable mechanical tensions on the FBGs. The presented sensor head is based on multiple FBGs inscribed in a lengthy single mode fiber. The sensor presents an average thermal sensitivity of 8.82 ± 0.09 pm/°C, resulting in a typical temperature resolution of ~0.1 °C and an average time constant value of 6.25 ± 0.08 s. Corrosion and degradation resistance were verified by infrared spectroscopy and scanning electron microscopy during 90 days exposure to high salinity crude oil samples. The developed sensor was tested in a field pilot test, mimicking the operation of an inland crude tank, demonstrating its abilities to dynamically monitor temperature profile. PMID:26690166

  10. Corrosion Resistant FBG-Based Quasi-Distributed Sensor for Crude Oil Tank Dynamic Temperature Profile Monitoring.

    PubMed

    Marques, Rogério da Silva; Prado, Adilson Ribeiro; Antunes, Paulo Fernando da Costa; André, Paulo Sérgio de Brito; Ribeiro, Moisés R N; Frizera-Neto, Anselmo; Pontes, Maria José

    2015-12-05

    This article presents a corrosion resistant, maneuverable, and intrinsically safe fiber Bragg grating (FBG)-based temperature optical sensor. Temperature monitoring is a critical activity for the oil and gas industry. It typically involves acquiring the desired parameters in a hazardous and corrosive environment. The use of polytetrafluoroethylene (PTFE) was proposed as a means of simultaneously isolating the optical fiber from the corrosive environment and avoiding undesirable mechanical tensions on the FBGs. The presented sensor head is based on multiple FBGs inscribed in a lengthy single mode fiber. The sensor presents an average thermal sensitivity of 8.82 ± 0.09 pm/°C, resulting in a typical temperature resolution of ~0.1 °C and an average time constant value of 6.25 ± 0.08 s. Corrosion and degradation resistance were verified by infrared spectroscopy and scanning electron microscopy during 90 days exposure to high salinity crude oil samples. The developed sensor was tested in a field pilot test, mimicking the operation of an inland crude tank, demonstrating its abilities to dynamically monitor temperature profile.

  11. Experimental study on the performance of pervious concrete

    NASA Astrophysics Data System (ADS)

    Liu, Haojie; Liu, Rentai; Yang, Honglu; Ma, Chenyang; Zhou, Heng

    2018-02-01

    With the construction of sponge city, the pervious concrete material has been developed rapidly. A high-performance pervious concrete is developed by using cement, silica fume (SF) and superplasticizer (SP). The effects of SF, SP, aggregate size, water-cement ration and aggregate-cement ratio on the permeability coefficient, compressive strength and flexural strength are studied by controlling variables, and exploring the corrosion resistance and abrasion resistance of pervious concrete. The results show that using 0.5% SP, 5% SF and small aggregate can greatly improve the strength. There is an optimum value for water-cement ratio to make the strength and permeability coefficient maximum. Compared to ordinary pervious concrete, the corrosion resistance and abrasion resistance of this pervious concrete are very good.

  12. 77 FR 31877 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-30

    ... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-350 and 731-TA-616 and 618 (Third Review)] Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five-Year Reviews... corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion...

  13. Resistance of Some Steels to Stress Corrosion Cracking

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Evaluations of stress-corrosion cracking resistance of five high-strength low-alloy steels described in report now available. Steels were heat-treated to various tensile strengths and found to be highly resistant to stress-corrosion cracking.

  14. Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments.

    PubMed

    Kassab, Elisa J; Gomes, José Ponciano

    2013-09-01

    To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride. NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy. Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium. There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.

  15. Corrosion behavior of high-strength spring steel for high-speed railway

    NASA Astrophysics Data System (ADS)

    Niu, Gang; Chen, Yin-li; Wu, Hui-bin; Wang, Xuan; Tang, Di

    2018-05-01

    The corrosion resistance and evolution of corrosion products in medium-carbon high-strength spring steels were investigated in a neutral salt spray (5wt% NaCl solution). A formation model of γ-FeOOH and a transformation model describing the conversion of γ-FeOOH to α-FeOOH were constructed. The results indicated that, at the initial corrosion stage, the corrosion resistance was gradually improved with the addition of Cr; however, with the addition of alloying element V, the corrosion resistance decreased. These results were attributed mainly to the initial corrosion stage being closely related to the matrix microstructure parameters such as grain-boundary character and dislocation density. After the rust layer was formed at a later corrosion stage, the corrosion resistance was reinforced with the addition of Cr and V because Cr strongly influenced the composition, structure, and morphology of the corrosion products. The results presented herein show that Cr was conducive to the transformation of γ-FeOOH into α-FeOOH. Moreover, V and Cr exhibited obvious synergy and were enriched in the inner layer of the corrosion products.

  16. Corrosion resistance of monolayer hexagonal boron nitride on copper

    PubMed Central

    Mahvash, F.; Eissa, S.; Bordjiba, T.; Tavares, A. C.; Szkopek, T.; Siaj, M.

    2017-01-01

    Hexagonal boron nitride (hBN) is a layered material with high thermal and chemical stability ideal for ultrathin corrosion resistant coatings. Here, we report the corrosion resistance of Cu with hBN grown by chemical vapor deposition (CVD). Cyclic voltammetry measurements reveal that hBN layers inhibit Cu corrosion and oxygen reduction. We find that CVD grown hBN reduces the Cu corrosion rate by one order of magnitude compared to bare Cu, suggesting that this ultrathin layer can be employed as an atomically thin corrosion-inhibition coating. PMID:28191822

  17. Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

    PubMed

    Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

    2015-01-01

    Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Corrosion resistance characteristics of a Ti-6Al-4V alloy scaffold that is fabricated by electron beam melting and selective laser melting for implantation in vivo.

    PubMed

    Zhao, Bingjing; Wang, Hong; Qiao, Ning; Wang, Chao; Hu, Min

    2017-01-01

    The purpose of this study is to determine the corrosion resistance of Ti-6Al-4V alloy fabricated with electron beam melting and selective laser melting for implantation in vivo. Ti-6Al-4V alloy specimens were fabricated with electron beam melting (EBM) and selective laser melting (SLM). A wrought form of Ti-6Al-4V alloy was used as a control. Surface morphology observation, component analysis, corrosion resistance experimental results, electrochemical impedance spectroscopy, crevice corrosion resistance experimental results, immersion test and metal ions precipitation analysis were processed, respectively. The thermal stability of EBM specimen was the worst, based on the result of open circuit potential (OCP) result. The result of electrochemical impedance spectroscopy indicated that the corrosion resistance of the SLM specimen was the best under the low electric potential. The result of potentiodynamic polarization suggested that the corrosion resistance of the SLM specimen was the best under the low electric potential (<1.5V) and EBM specimen was the best under the high electric potential (>1.5V).The crevice corrosion resistance of the EBM specimen was the best. The corrosion resistance of SLM specimen was the best, based on the result of immersion test. The content of Ti, Al and V ions of EBM, SLM and wrought specimens was very low. In general, the scaffolds that were fabricated with EBM and SLM had good corrosion resistance, and were suitable for implantation in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Environmental protection to 922K (1200 F) for titanium alloys

    NASA Technical Reports Server (NTRS)

    Groves, M. T.

    1973-01-01

    Evaluations are presented of potential coating systems for protection of titanium alloys from hot-salt stress-corrosion up to temperatures of 755 K (900 F) and from oxidation embrittlement up to temperature of 922 K (1200 F). Diffusion type coatings containing Si, Al, Cr, Ni or Fe as single coating elements or in various combinations were evaluated for oxidation protection, hot-salt stress-corrosion (HSSC) resistance, effects on tensile properties, fatigue properties, erosion resistance and ballistic impact resistance on an alpha and beta phase titanium alloy (Ti-6Al-2Sn-4Zr-2Mo). All of the coatings investigated demonstrated excellent oxidation protectiveness, but none of the coatings provided protection from hot-salt stress-corrosion. Experimental results indicated that both the aluminide and silicide types of coatings actually decreased the HSSC resistance of the substrate alloy. The types of coatings which have typically been used for oxidation protection of refractory metals and nickel base superalloys are not suitable for titanium alloys because they increase the susceptibility to hot-salt stress-corrosion, and that entirely new coating concepts must be developed for titanium alloy protection in advanced turbine engines.

  20. Pitting Corrosion Behaviour of New Corrosion-Resistant Reinforcement Bars in Chloride-Containing Concrete Pore Solution

    PubMed Central

    Liu, Yao; Chu, Hong-yan; Wang, Danqian; Ma, Han; Sun, Wei

    2017-01-01

    In this study, the pitting behaviour of a new corrosion-resistant alloy steel (CR) is compared to that of low-carbon steel (LC) in a simulated concrete pore solution with a chloride concentration of 5 mol/L. The electrochemical behaviour of the bars was characterised using linear polarisation resistance (LPR) and electrochemical impedance spectroscopy (EIS). The pitting profiles were detected by reflective digital holographic microscopy (DHM), scanning electron microscopy (SEM), and the chemical components produced in the pitting process were analysed by X-ray energy dispersive spectroscopy (EDS). The results show that the CR bars have a higher resistance to pitting corrosion than the LC bars. This is primarily because of the periodic occurrence of metastable pitting during pitting development. Compared to the pitting process in the LC bars, the pitting depth grows slowly in the CR bars, which greatly reduces the risk of pitting. The possible reason for this result is that the capability of the CR bars to heal the passivation film helps to restore the metastable pits to the passivation state. PMID:28777327

  1. 16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

  2. 16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

  3. 16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

  4. 16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

  5. 16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

  6. Machining-induced surface transformations of magnesium alloys to enhance corrosion resistance in human-like environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bruschi, Stefania; Bertolini, Rachele; Ghiotti, Andrea

    We report that magnesium alloys are becoming increasingly attractive for producing temporary prosthetic devices thanks to their bioresorbable characteristics in human body. However, their poor corrosion resistance to body fluids seriously limits their applicability. In this work, machining-induced surface transformations are explored as means to enhance corrosion resistance of AZ31 magnesium alloy. Surface characteristics including topography, residual stresses, wettability, microstructures and depth of transformed layer, were analysed and correlated to in-vitro corrosion resistance. Results showed that cryogenic machining at low feed provided the most promising corrosion reduction. Finally, thorough physical characterizations gave fundamental insights into possible drivers for this enhancedmore » resistance.« less

  7. Machining-induced surface transformations of magnesium alloys to enhance corrosion resistance in human-like environment

    DOE PAGES

    Bruschi, Stefania; Bertolini, Rachele; Ghiotti, Andrea; ...

    2018-04-22

    We report that magnesium alloys are becoming increasingly attractive for producing temporary prosthetic devices thanks to their bioresorbable characteristics in human body. However, their poor corrosion resistance to body fluids seriously limits their applicability. In this work, machining-induced surface transformations are explored as means to enhance corrosion resistance of AZ31 magnesium alloy. Surface characteristics including topography, residual stresses, wettability, microstructures and depth of transformed layer, were analysed and correlated to in-vitro corrosion resistance. Results showed that cryogenic machining at low feed provided the most promising corrosion reduction. Finally, thorough physical characterizations gave fundamental insights into possible drivers for this enhancedmore » resistance.« less

  8. Effect of the Parameters of Gas-Powder Laser Surfacing on the Structural Characteristics of Reconditioned Surface Layer of Corrosion-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Krylova, S. E.; Oplesnin, S. P.; Manakov, N. A.; Yasakov, A. S.; Strizhov, A. O.

    2018-01-01

    Results of the developed commercial process for reconditioning the surface of corrosion-resistant steels by the method of laser surfacing are presented. A comparative analysis of the microstructures of the deposited wear-resistant layer, of the zone of fusion with the matrix material and of the diffusion zone after different variants of surfacing is performed. The hardness of the deposited layer is measured and a nondestructive inspection of the latter for the presence of flaws is performed.

  9. The effects of argon ion bombardment on the corrosion resistance of tantalum

    NASA Astrophysics Data System (ADS)

    Ramezani, A. H.; Sari, A. H.; Shokouhy, A.

    2017-02-01

    Application of ion beam has been widely used as a surface modification method to improve surface properties. This paper investigates the effect of argon ion implantation on surface structure as well as resistance against tantalum corrosion. In this experiment, argon ions with energy of 30 keV and in doses of 1 × 1017-10 × 1017 ions/cm2 were used. The surface bombardment with inert gases mainly produces modified topography and morphology of the surface. Atomic Force Microscopy was also used to patterned the roughness variations prior to and after the implantation phase. Additionally, the corrosion investigation apparatus wear was applied to compare resistance against tantalum corrosion both before and after ion implantation. The results show that argon ion implantation has a substantial impact on increasing resistance against tantalum corrosion. After the corrosion test, scanning electron microscopy (SEM) analyzed the samples' surface morphologies. In addition, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. The purpose of this paper was to obtain the perfect condition for the formation of tantalum corrosion resistance. In order to evaluate the effect of the ion implantation on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation doses.

  10. Effect of Alloying Elements on Tensile Properties, Microstructure, and Corrosion Resistance of Reinforcing Bar Steel

    NASA Astrophysics Data System (ADS)

    Panigrahi, B. K.; Srikanth, S.; Sahoo, G.

    2009-11-01

    The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt.%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.

  11. An Investigation of Anaerobic Processes in Fuel/Natural Seawater Environments

    DTIC Science & Technology

    2012-02-08

    Corrosion rates were estimated from polarization resistance measurements and corrosion was measured by weight loss. Corrosion attack morphology and...rates were estimated from polarization resistance measurements and corrosion was measured by weight loss. Corrosion attack morphology and corrosion...the backside of the coupons with conductive epoxy and carbon tape to achieve electrical connection. Coupons were individually mounted in epoxy to

  12. Explosion Clad for Upstream Oil and Gas Equipment

    NASA Astrophysics Data System (ADS)

    Banker, John G.; Massarello, Jack; Pauly, Stephane

    2011-01-01

    Today's upstream oil and gas facilities frequently involve the combination of high pressures, high temperatures, and highly corrosive environments, requiring equipment that is thick wall, corrosion resistant, and cost effective. When significant concentrations of CO2 and/or H2S and/or chlorides are present, corrosion resistant alloys (CRA) can become the material of choice for separator equipment, piping, related components, and line pipe. They can provide reliable resistance to both corrosion and hydrogen embrittlement. For these applications, the more commonly used CRA's are 316L, 317L and duplex stainless steels, alloy 825 and alloy 625, dependent upon the application and the severity of the environment. Titanium is also an exceptional choice from the technical perspective, but is less commonly used except for heat exchangers. Explosion clad offers significant savings by providing a relatively thin corrosion resistant alloy on the surface metallurgically bonded to a thick, lower cost, steel substrate for the pressure containment. Developed and industrialized in the 1960's the explosion cladding technology can be used for cladding the more commonly used nickel based and stainless steel CRA's as well as titanium. It has many years of proven experience as a reliable and highly robust clad manufacturing process. The unique cold welding characteristics of explosion cladding reduce problems of alloy sensitization and dissimilar metal incompatibility. Explosion clad materials have been used extensively in both upstream and downstream oil, gas and petrochemical facilities for well over 40 years. The explosion clad equipment has demonstrated excellent resistance to corrosion, embrittlement and disbonding. Factors critical to insure reliable clad manufacture and equipment design and fabrication are addressed.

  13. 46 CFR 162.017-3 - Materials, construction, and workmanship.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-resistant wire mesh with a 1/2-inch corrosion-resistant separator on a single screen of 30×30 corrosion-resistant wire mesh shall be fitted on all openings to atmosphere. The net free area through the flame... are not acceptable. (e) Flame screens shall be made of corrosion-resistant wire. (f) Nonmetallic...

  14. Microstructure Evolution and Selective Corrosion Resistance in Underwater Multi-pass 2101 Duplex Stainless Steel Welding Joints

    NASA Astrophysics Data System (ADS)

    Hu, Yu; Shi, Yonghua; Shen, Xiaoqin; Wang, Zhongmin

    2018-05-01

    A recently developed promising material, 2101 lean duplex stainless steel, represents an alternative to 304 austenite stainless steel. In this work, multi-pass 2101 weld joints were fabricated using the flux-cored arc welding method in a hyperbaric chamber. The pressure varied from 0 to 0.75 MPa. The evolution of the welding process and microstructure was investigated. γ 2 formation in the reheated zones of the WM and HAZ was not uniform. The closer the reheated zone is to the subsequent heat source, the greater the γ 2 formation in the reheated zone. Sufficient primary austenite transformation inhibited Cr2N precipitation and the subsequent intragranular γ 2 formation in the reheated weld passes of the 0.45 MPa weld metal. The localized corrosion resistance of each zone of the 0.45 MPa DSS joint was measured using non-destructive double-loop electrochemical potentiokinetic reactivation tests. The localized corrosion was induced by γ 2 and Cr2N. The root region of the 0.45 MPa weld metal underwent two subsequent welding thermal cycles, which induced increased γ 2 formation and lower resistance to corrosion because of the decreased pitting resistance value of γ 2. The correlation between microstructure evolution and the distribution of selective corrosion was determined.

  15. Development of a unique polyurethane primer/topcoat

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Klotz, James M.

    1994-01-01

    USBI Company, a Division of Pratt & Whitney Government Engines and Space Propulsion, is involved in corrosion and environmental research and development activities both at their headquarters in Huntsville, Alabama and their Florida Operations at Kennedy Space Center, Florida. The programs involve the development of environmentally compatible materials that improve the corrosion protection of expensive Solid Rocket Boosters (SRB) that are part of the Space Shuttle systems developed and managed by Marshall Space Flight Center in Huntsville, Alabama. Coatings For Industry, a paint manufacturer in Souderton, PA helped formulate and produce the first lot of BOOSTERCOAT paint. High strength aluminum aerospace flight hardware exposed to harsh seacoast environments and seawater immersion presently uses high volatile organic compound (VOC) chromated and lead bearing primers and epoxy topcoats for corrosion protection. Epoxy paint tends to be brittle and has relatively low ultraviolet (UV) exposure resistance. A unique, environmentally compatible, non-leaded/non-chromated, low VOC polyurethane single coat (primer/topcoat) trade named BOOSTERCOAT has been developed for excellent corrosion protection, flexibility, adhesion, chemical and solvent resistance properties. This report will discuss the development of BOOSTERCOAT and the potential opportunities for commercial use in the energy, transportation, chemical, maritime, structural fields.

  16. Resistance of Silicon Nitride Turbine Components to Erosion and Hot Corrosion/oxidation Attack

    NASA Technical Reports Server (NTRS)

    Strangmen, Thomas E.; Fox, Dennis S.

    1994-01-01

    Silicon nitride turbine components are under intensive development by AlliedSignal to enable a new generation of higher power density auxiliary power systems. In order to be viable in the intended applications, silicon nitride turbine airfoils must be designed for survival in aggressive oxidizing combustion gas environments. Erosive and corrosive damage to ceramic airfoils from ingested sand and sea salt must be avoided. Recent engine test experience demonstrated that NT154 silicon nitride turbine vanes have exceptional resistance to sand erosion, relative to superalloys used in production engines. Similarly, NT154 silicon nitride has excellent resistance to oxidation in the temperature range of interest - up to 1400 C. Hot corrosion attack of superalloy gas turbine components is well documented. While hot corrosion from ingested sea salt will attack silicon nitride substantially less than the superalloys being replaced in initial engine applications, this degradation has the potential to limit component lives in advanced engine applications. Hot corrosion adversely affects the strength of silicon nitride in the 850 to 1300 C range. Since unacceptable reductions in strength must be rapidly identified and avoided, AlliedSignal and the NASA Lewis Research Center have pioneered the development of an environmental life prediction model for silicon nitride turbine components. Strength retention in flexure specimens following 1 to 3300 hour exposures to high temperature oxidation and hot corrosion has been measured and used to calibrate the life prediction model. Predicted component life is dependent upon engine design (stress, temperature, pressure, fuel/air ratio, gas velocity, and inlet air filtration), mission usage (fuel sulfur content, location (salt in air), and times at duty cycle power points), and material parameters. Preliminary analyses indicate that the hot corrosion resistance of NT154 silicon nitride is adequate for AlliedSignal's initial engine applications. Protective coatings and/or inlet air filtration may be required to achieve required ceramic component lives in more aggressive environments.

  17. Hot corrosion resistance of nickel-chromium-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.; Barret, C. A.

    1977-01-01

    The hot corrosion resistance of nickel-chromium-aluminum alloys was examined by cyclically oxidizing sodium sulfate-coated specimens in still air at 900, 1000, and 1100 C. The compositions tested were within the ternary region: Ni, Ni-50 at.% Cr, and Ni-50 at.% Al. At each temperature the corrosion data were statistically fitted to a third order regression equation as a function of chromium and aluminum contents. From these equations corrosion isopleths were prepared. Compositional regions with the best hot corrosion resistance were identified.

  18. Hot corrosion resistance of nickel-chromium-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.; Barrett, C. A.

    1977-01-01

    The hot corrosion resistance of nickel-chromium-aluminum alloy was examined by cyclically oxidizing sodium sulfate coated specimens in still air at 900, 1000 and 1100 C. The compositions tested were within the ternary region: Ni; Ni-50 at.% Cr; and Ni-50 at.% Al. At each temperature the corrosion data were statistically fitted to a third order regression equation as a function of chromium and aluminum contents. Corrosion isopleths were prepared from these equations. Compositional regions with the best hot corrosion resistance were identified.

  19. Research to develop guidelines for cathodic protection of concentric neutral cables, volume 1

    NASA Astrophysics Data System (ADS)

    Hanck, J. A.; Nekoksa, G.

    1981-08-01

    Data associated with corrosion of concentric neutrals (CN) of direct buried cables from field tests conducted at 36 bellholes excavated in California, Oklahoma, and North Carolina are presented. The electrochemical, chemical, bacteriological, and sieve analyses of native soil and imported backfill samples are included. Up to 129 values were determined for each bellhole and stored on cards as a data bank. All values were statistically analyzed and correlated with corrosion found. The severity of corrosion correlated best with CN corrosion potentials, CN resistance measurements, coarseness of backfill, and soil resistivity. The guidelines for installation of cathodic protection on CN cables are to be based upon the evaluation of over 100 experimental cathodic protection systems and upon laboratory testing for protection criteria with and without ac effects.

  20. Microstructure Analysis of Ti-xPt Alloys and the Effect of Pt Content on the Mechanical Properties and Corrosion Behavior of Ti Alloys

    PubMed Central

    Song, Ho-Jun; Han, Mi-Kyung; Jeong, Hyeon-Gyeong; Lee, Yong-Tai; Park, Yeong-Joon

    2014-01-01

    The microstructure, mechanical properties, and corrosion behavior of binary Ti-xPt alloys containing 5, 10, 15 and 20 wt% Pt were investigated in order to develop new Ti-based dental materials possessing superior properties than those of commercially pure titanium (cp-Ti). All of the Ti-xPt (x = 5, 10, 15, 20) alloys showed hexagonal α-Ti structure with cubic Ti3Pt intermetallic phase. The mechanical properties and corrosion behavior of Ti-xPt alloys were sensitive to the Pt content. The addition of Pt contributed to hardening of cp-Ti and to improving its oxidation resistance. Electrochemical results showed that the Ti-xPt alloys exhibited superior corrosion resistance than that of cp-Ti. PMID:28788660

  1. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ballinger, Ronald G

    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 corrosionmore » 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 core. This FGC represents an enabling technology for LBE cooled fast reactors.« less

  2. Improvement of corrosion protection property of Mg-alloy by DLC and Si-DLC coatings with PBII technique and multi-target DC-RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Masami, Ikeyama; Setsuo, Nakao; Tsutomu, Sonoda; Junho, Choi

    2009-05-01

    Magnesium alloys have been considered as one of the most promising light weight materials with potential applications for automobile and aircraft components. Their poor corrosion resistance, however, has to date prevented wider usage. Diamond-like carbon (DLC) and silicon-incorporated DLC (Si-DLC) coatings are known to provide a high degree of corrosion protection, and hold accordingly promise for enhancing the corrosion resistance of the magnesium alloys. In this work we have studied the effect of coating conditions of DLC coatings as well as Si incorporation into coating on corrosion resistance, deposited onto AZ91 magnesium alloy substrates by plasma based ion implantation (PBII). The influences of a Ti interlayer beneath the DLC, Si-DLC and Ti incorporated DLC (Ti-DLC) coatings fabricated by multi-target direct-current radio-frequency (DC-RF) magnetron sputtering were also examined on both the adhesion strength and corrosion resistance of the materials. We have also examined the effect of the Si content in the Si-DLC coatings made by magnetron sputtering on the alloys' corrosion resistance. The results of potentiodynamic polarization measurements demonstrate that Si-DLC coating deposited by PBII exhibits the highest corrosion resistance in an aqueous 0.05 M NaCl solution. Although Ti layer is helpful in increasing adhesion between DLC coating and AZ91 substrate, it also influences adversely corrosion protection. The ozone treatment of the magnesium alloy's surface before the formation of coatings has been found to improve both adhesion strength and corrosion resistance.

  3. 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.

  4. Corrosion anisotropy of titanium deformed by the hydrostatic extrusion

    NASA Astrophysics Data System (ADS)

    Chojnacka, A.; Kawalko, J.; Koscielny, H.; Guspiel, J.; Drewienkiewicz, A.; Bieda, M.; Pachla, W.; Kulczyk, M.; Sztwiertnia, K.; Beltowska-Lehman, E.

    2017-12-01

    The corrosion behaviour of titanium rods deformed by hydrostatic extrusion (HE) in artificial saliva (Carter-Brugirard's solution of pH 7.6) was investigated using open-circuit potentials (OCPs), (DC) potentiodynamic polarisation curves and (AC) electrochemical impedance spectroscopy (EIS) techniques. Various electrochemical parameters (corrosion potential Ecorr, corrosion current (icorr), polarisation resistance Rp, charge transfer resistance Rct and oxide film resistance Rf) were analysed. Significant coherence was observed between results achieved from these procedures, i.e., all applied techniques showed the same trend for corrosion resistance. The obtained electrochemical data were then related to the microstructure parameters (crystallographic texture, grain size, grain boundary distribution and density) determined using the EBSD/SEM technique. It was found that the corrosion behaviour of titanium processed by the HE method was superior compared to the unprocessed Ti, and this was clearly dependent on the extrusion direction. The highest corrosion resistance was revealed for the HE-deformed Ti rod of the surface oriented longitudinal (parallel) to the extrusion direction.

  5. Effect of Environmental Exposures on Fatigue Life of P/M Disk Superalloys

    NASA Technical Reports Server (NTRS)

    Draper, Susan

    2011-01-01

    As the temperature capability of Ni-base superalloy powder metallurgy disks is steadily increased, environmental resistance and protection of advanced nickel-based turbine disk components are becoming increasingly important. Localized surface hot corrosion attack and damage from oxidation have been shown to impair disk fatigue life and may eventually limit disk operating temperatures. NASA Research Announcement (NRA) contracts have been awarded to GE Aviation and Honeywell Aerospace to separately develop fatigue resistant metallic and ceramic coatings for corrosion resistance and the corrosion/fatigue results of selected coatings will be presented. The microstructural response of a bare ME3 disk superalloy has been evaluated for moderate (704 C) and aggressive (760-816 C) oxidizing exposures up to 2,020 hours. Cross section analysis reveals sub-surface damage (significant for aggressive exposures) that consists of Al2O3 "fingers", interfacial voids, a recrystallized precipitate-free layer and GB carbide dissolution. The effects of a Nichrome corrosion coating on this microstructural response will also be presented.

  6. Is cell viability always directly related to corrosion resistance of stainless steels?

    PubMed

    Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. 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.

  8. Argon Shrouded Plasma Spraying of Tantalum over Titanium for Corrosion Protection in Fluorinated Nitric Acid Media

    NASA Astrophysics Data System (ADS)

    Vetrivendan, E.; Jayaraj, J.; Ningshen, S.; Mallika, C.; Kamachi Mudali, U.

    2018-02-01

    Argon shrouded plasma spraying (ASPS) was used to deposit a Ta coating on commercially pure Ti (CP-Ti) under inert argon, for dissolver vessel application in the aqueous spent fuels reprocessing plant with high plutonium content. Oxidation during plasma spraying was minimized by shrouding argon system. Porosity and oxide content were controlled by optimizing the spraying parameters, to obtain a uniform and dense Ta coating. The Ta particle temperature and velocity were optimized by judiciously controlling the spray parameters, using a spray diagnostic charge-coupled device camera. The corrosion resistance of the Ta coatings developed by ASPS was investigated by electrochemical studies in 11.5 M HNO3 and 11.5 M HNO3 + 0.05 M NaF. Similarly, the durability of the ASPS Ta coating/substrate was evaluated as per ASTM A262 Practice-C test in boiling nitric acid and fluorinated nitric acid for 240 h. The ASPS Ta coating exhibited higher corrosion resistance than the CP-Ti substrate, as evident from electrochemical studies, and low corrosion rate with excellent coating stability in boiling nitric, and fluorinated nitric acid. The results of the present study revealed that tantalum coating by ASPS is a promising strategy for improving the corrosion resistance in the highly corrosive reprocessing environment.

  9. Laser Nitriding of the Newly Developed Ti-20Nb-13Zr at.% Biomaterial Alloy to Enhance Its Mechanical and Corrosion Properties in Simulated Body Fluid

    NASA Astrophysics Data System (ADS)

    Hussein, M. A.; Kumar, A. Madhan; Yilbas, Bekir S.; Al-Aqeeli, N.

    2017-11-01

    Despite the widespread application of Ti alloy in the biomedical field, surface treatments are typically applied to improve its resistance to corrosion and wear. A newly developed biomedical Ti-20Nb-13Zr at.% alloy (TNZ) was laser-treated in nitrogen environment to improve its surface characteristics with corrosion protection performance. Surface modification of the alloy by laser was performed through a Nd:YAG laser. The structural and surface morphological alterations in the laser nitrided layer were investigated by XRD and a FE-SEM. The mechanical properties have been evaluated using nanoindentation for laser nitride and as-received samples. The corrosion protection behavior was estimated using electrochemical corrosion analysis in a physiological medium (SBF). The obtained results revealed the production of a dense and compact film of TiN fine grains (micro-/nanosize) with 9.1 µm below the surface. The mechanical assessment results indicated an improvement in the modulus of elasticity, hardness, and resistance of the formed TiN layer to plastic deformation. The electrochemical analysis exhibited that the surface protection performance of the laser nitrided TNZ substrates in the SBF could be considerably enhanced compared to that of the as-received alloy due to the presence of fine grains in the TiN layer resulting from laser nitriding. Furthermore, the untreated and treated Ti-20Nb-13Zr alloy exhibited higher corrosion resistance than the CpTi and Ti6Al4V commercial alloys. The improvements in the surface hardness and corrosion properties of Ti alloy in a simulated body obtained using laser nitriding make this approach a suitable candidate for enhancing the properties of biomaterials.

  10. Anticorrosion performance of chromized coating prepared by pack cementation in simulated solution with H2S and CO2

    NASA Astrophysics Data System (ADS)

    Wang, Qin-Ying; Behnamian, Yashar; Luo, Hong; Wang, Xian-Zong; Leitch, Michael; Zeng, Hongbo; Luo, Jing-Li

    2017-10-01

    A hash service environment containing H2S and CO2 in oil industry usually causes corrosion of carbon steel. In this study, the chromized coatings with different deposited time were prepared on the surface of carbon steel by the method of pack cementation to enhance its corrosion resistance. Then the microstructure, hardness, corrosion resistance as well as the semiconductor behavior of coatings in the simulated solution with saturated H2S and CO2 were investigated. The results show that the content of Cr in coating was increased by prolonging deposited time, and both chromium carbides and chromium nitrides were formed. Furthermore, coatings display higher polarization resistance, Rp, than that of the substrate, indicating a higher resistance to charge transfer on coating surface. The corrosion rates of coatings with different deposited time were significantly lower than that of substrate. Chemical analysis showed the formation of heavy sulfides on the surface of substrates after corrosion, while the least corrosion products were detected on the surface of coating with deposited time of 12 h. Mott-Schottky results indicated that coating of 12 h displayed less defects than the other two coatings with deposited time of 4 h and 8 h, which will be beneficial to improve corrosion resistance. The investigation showed that chromized coatings exhibited high corrosion resistance and owned a potential application in oil industry for corrosion prevention.

  11. High Corrosion Resistance Offered by Multi-Walled Carbon Nanotubes Directly Grown Over Mild Steel Substrate

    NASA Astrophysics Data System (ADS)

    Arora, Sweety; Rekha, M. Y.; Gupta, Abhay; Srivastava, Chandan

    2018-02-01

    The inert and hydrophobic nature of carbon nanotubes (CNTs) makes them a potential material for corrosion protection coatings. In this work, a uniform coating of multi-walled CNTs (MWCNTs) was formed over a mild steel substrate by direct decomposition of a ferrocene-benzene mixture over the substrate which was kept inside a chemical vapor deposition setup at a temperature of 800°C. The MWCNTs formed over the substrate were characterized using x-ray diffraction, Raman spectroscopy and transmission electron microscopy techniques. Corrosion behavior of the bare and MWCNT-coated mild steel substrate was examined through potentiodynamic polarization and electrochemical impedance spectroscopy methods. A significant improvement in the corrosion resistance in terms of the reduction in corrosion current and corrosion rate and increase in polarization resistance was noted in the case of the MWCNT-coated mild steel plate. Corrosion resistance increased due to MWCNT coating.

  12. Thermal effects of laser marking on microstructure and corrosion properties of stainless steel.

    PubMed

    Švantner, M; Kučera, M; Smazalová, E; Houdková, Š; Čerstvý, R

    2016-12-01

    Laser marking is an advanced technique used for modification of surface optical properties. This paper presents research on the influence of laser marking on the corrosion properties of stainless steel. Processes during the laser beam-surface interaction cause structure and color changes and can also be responsible for reduction of corrosion resistance of the surface. Corrosion tests, roughness, microscopic, energy dispersive x-ray, grazing incidence x-ray diffraction, and ferrite content analyses were carried out. It was found that increasing heat input is the most crucial parameter regarding the degradation of corrosion resistance of stainless steel. Other relevant parameters include the pulse length and pulse frequency. The authors found a correlation between laser processing parameters, grazing incidence x-ray measurement, ferrite content, and corrosion resistance of the affected surface. Possibilities and limitations of laser marking of stainless steel in the context of the reduction of its corrosion resistance are discussed.

  13. Corrosion-resistant antifretting coating for the protection of blade locking pieces in GTE compressors and fans

    NASA Astrophysics Data System (ADS)

    Muboyadzhyan, S. A.; Gorlov, D. S.; Egorova, L. P.; Bulavintseva, E. E.

    2014-09-01

    The properties of a corrosion-resistant antifretting coating on EP866Sh steel and VT8M-1 titanium alloy samples are studied. The results of corrosion resistance, heat resistance, fretting resistance, long-term strength, and high-cycle fatigue tests and the results of physical metallurgy and metallographic investigations of the samples with the coating before and after the tests are presented.

  14. Corrosion resistance and durability of superhydrophobic surface formed on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution.

    PubMed

    Ishizaki, Takahiro; Masuda, Yoshitake; Sakamoto, Michiru

    2011-04-19

    The corrosion resistant performance and durability of the superhydrophobic surface on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution were investigated using electrochemical and contact angle measurements. The durability of the superhydrophobic surface in corrosive 5 wt% NaCl aqueous solution was elucidated. The corrosion resistant performance of the superhydrophobic surface formed on magnesium alloy was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the superhydrophobic surface considerably improved the corrosion resistant performance of magnesium alloy AZ31. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test was performed to investigate the adhesion of the superhydrophobic film to the magnesium alloy surface. The corrosion formation mechanism of the superhydrophobic surface formed on the magnesium alloy was also proposed. © 2011 American Chemical Society

  15. Oxidation And Hot Corrosion Of ODS Alloy

    NASA Technical Reports Server (NTRS)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

    Report reviews oxidation and hot corrosion of oxide-dispersion-strengthened (ODS) alloys, intended for use at high temperatures. Classifies environmental resistances of such alloys by rates of growth of oxides, volatilities of oxides, spalling of oxides, and limitations imposed by hot corrosion. Also discusses environmentally resistant coatings for ODS materials. Concludes ODS NICrAl and FeCrAl alloys highly resistant to oxidation and corrosion and can be used uncoated.

  16. The oxidation and corrosion of ODS alloys

    NASA Technical Reports Server (NTRS)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

    The oxidation and hot corrosion of high temperature oxide dispersion strengthened (ODS) alloys are reviewed. The environmental resistance of such alloys are classified by oxide growth rate, oxide volatility, oxide spalling, and hot corrosion limitations. Also discussed are environmentally resistant coatings for ODS materials. It is concluded that ODS NiCrAl and FeCrAl alloys are highly oxidation and corrosion resistant and can probably be used uncoated.

  17. The resistance of high frequency inductive welded pipe to grooving corrosion in salt water

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duran, C.; Triess, E.; Herbsleb, G.

    1986-09-01

    When exposed to neutral, salt-containing waters, electric resistant welded pipe in carbon and low alloy steels with increased sulfur contents may suffer preferential corrosion attack in the weld area. Because of its appearance, this type of corrosion is called grooving corrosion. The susceptibility to grooving corrosion may be determined and quantitatively described by means of an accelerated potentiostatic exposure test. The importance of type, concentration, and temperature of the electrolytic solution; potential; test duration; and the sulfur content of the steel in the accelerated corrosion test and the susceptibility of steels to grooving corrosion are described. Line pipe in highmore » frequency inductive (HFI) welded carbon and low alloy steels are resistant to grooving corrosion particularly because of their low sulfur content.« less

  18. Identification of commercially available alloys for corrosion-resistant metallic reinforcement and test methods for evaluating corrosion-resistant reinforcement.

    DOT National Transportation Integrated Search

    2008-01-01

    A literature review was conducted with the goal of identifying alternative low-cost corrosion-resistant steel reinforcement materials. The most promising alternate reinforcing materials seen to date that are less expensive than 300 series stainless s...

  19. Research on Performance and Microstructure of Sewage Pipe Mortar Strengthened with Different Anti-Corrosion Technologies

    NASA Astrophysics Data System (ADS)

    Mu, Song; Zhou, Huaxin; Shi, Liang; Liu, Jianzhong; Cai, Jingshun; Wang, Feng

    2017-10-01

    Mostly urban underground sewage is the acidic corrosion environment with a high concentration of aggressive ions and microbe, which resulted in performance deterioration and service-life decrease of sewage concrete pipe. In order to effectively protect durability of the concrete pipe, the present paper briefly analysed the main degradation mechanism of concrete pipe attacked by urban underground sewage, and proposed that using penetrating and strengthening surface sealer based on inorganic chemistry. In addition, using index of compressive strength, weight loss and appearance level to investigate the influence of the sealer on corrosion resistance of mortar samples after different dry-wet cycles. Besides, comparative research on effect of the sealer, aluminate cement and admixture of corrosion resistance was also addressed. At last, the SEM technology was used to reveal the improvement mechanism of different technologies of corrosion resistance. The results indicated that the sealer and aluminate cement can significantly improve corrosion resistance of mortar. Besides, the improvement effect can be described as the descending order: the penetrating and strengthening surface sealer > aluminate cement > admixture of corrosion resistance. The mortar sample treated with the sealer displayed the condensed and sound microstructure which proved that the sealer can improve the corrosion resistance to urban underground sewage.

  20. Scientific Fundamentals and Technological Development of Novel Biocompatible/Corrosion Resistant Ultrananocrystalline Diamond (UNCD) Coating Enabling Next Generation Superior Metal-Based Dental Implants

    NASA Astrophysics Data System (ADS)

    Kang, Karam

    Current Ti-based dental implants exhibit failure (2-10%), due to various mechanisms, including chemical corrosion of the surface of the TiO2 naturally covered Ti-based implants. This thesis focused on developing a unique biocompatible/bio-inert/corrosion resistant/low cost Ultrananocrystalline Diamond (UNCD) coating (with 3-5 nm grain size) for encapsulation of Tibased micro-implants to potentially eliminate the corrosion/mechanical induced failure of current commercial Ti-based dental implants. Microwave Plasma Chemical Vapor Deposition (MPCVD) and Hot Filament Chemical Vapor Deposition (HFCVD) processes were used to grow UNCD coatings. The surface topography and chemistry of UNCD coatings were characterized using scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopies (XPS) respectively. In conclusion, this thesis contributed to establish the optimal conditions to grow UNCD coatings on the complex 3-D geometry of Ti-based micro-implants, with geometry similar to real implants, relevant to developing UNCD-coated Ti-based dental implants with superior mechanical/chemical performance than current Ti-based implants.

  1. Corrosion Behavior of Additive Manufactured Ti-6Al-4V Alloy in NaCl Solution

    NASA Astrophysics Data System (ADS)

    Yang, Jingjing; Yang, Huihui; Yu, Hanchen; Wang, Zemin; Zeng, Xiaoyan

    2017-07-01

    The microstructures, potentiodynamic curves, and electrochemical impedance spectroscopy are characterized for Ti-6Al-4V samples produced by selective laser melting (SLM), SLM followed by heat treatment (HT), wire and arc additive manufacturing (WAAM), and traditional rolling to investigate their corrosion behaviors. Results show that the processing technology acts a significant role in controlling the microstructures, which in turn directly determine their corrosion resistance. The order of corrosion resistance of these samples is SLM < WAAM < rolling < SLM+HT. Among these microstructural factors for influencing corrosion resistance, type of constituent phase is the main one, followed by grain size, and the last is morphology. Finally, the application potentials of additive manufactured Ti-6Al-4V alloy are verified in the aspect of corrosion resistance.

  2. Development of Ferrium S53 High-Strength, Corrosion-Resistant Steel

    DTIC Science & Technology

    2009-01-01

    strength steel used in landing gear, and equivalent in corrosion resistance to the lower strength 15-5PH stainless steel used in actuators. It also...5PH stainless steel used in modern aerospace actuators. These objectives were met, with two minor exceptions: (1) the tensile yield of S53 is... stainless steel used in modern aerospace actuators. The work was initially funded as a 1-year SERDP proof-of-principle project. In this first

  3. Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen

    NASA Astrophysics Data System (ADS)

    Chan, Chi-Wai; Lee, Seunghwan; Smith, Graham; Sarri, Gianluca; Ng, Chi-Ho; Sharba, Ahmed; Man, Hau-Chung

    2016-03-01

    The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti-Nb-Zr-Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti-35.3Nb-7.3Zr-5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks' solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

  4. Research and development issues for molten carbonate fuel cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Krumpelt, M.

    1996-04-01

    This paper describes issues pertaining to the development of molten carbonate fuel cells. In particular, the corrosion resistance and service life of nickel oxide cathodes is described. The resistivity of lithium oxide/iron oxides and improvement with doping is addressed.

  5. High Velocity Oxidation and Hot Corrosion Resistance of Some ODS Alloys

    NASA Technical Reports Server (NTRS)

    Lowell, C. E.; Deadmore, D. L.

    1977-01-01

    Several oxide dispersion strengthened (ODS) alloys were tested for cyclic, high velocity, oxidation, and hot corrosion resistance. These results were compared to the resistance of an advanced, NiCrAl coated superalloy. An ODS FeCrAl were identified as having sufficient oxidation and hot corrosion resistance to allow potential use in an aircraft gas turbine without coating.

  6. Toward more environmentally resistant gas turbines: Progress in NASA-Lewis programs

    NASA Technical Reports Server (NTRS)

    Lowell, C. E.; Grisaffe, S. J.; Levine, S. R.

    1976-01-01

    A wide range of programs are being conducted for improving the environmental resistance to oxidation and hot corrosion of gas turbine and power system materials. They range from fundamental efforts to delineate attack mechanisms, allow attack modeling and permit life prediction, to more applied efforts to develop potentially more resistant alloys and coatings. Oxidation life prediction efforts have resulted in a computer program which provides an initial method for predicting long time metal loss using short time oxidation data by means of a paralinear attack model. Efforts in alloy development have centered on oxide-dispersion strengthened alloys based on the Ni-Cr-Al system. Compositions have been identified which are compromises between oxidation and thermal fatigue resistance. Fundamental studies of hot corrosion mechanisms include thermodynamic studies of sodium sulfate formation during turbine combustion. Information concerning species formed during the vaporization of Na2SO4 has been developed using high temperature mass spectrometry.

  7. Modeling pore corrosion in normally open gold- plated copper connectors.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Battaile, Corbett Chandler; Moffat, Harry K.; Sun, Amy Cha-Tien

    2008-09-01

    The goal of this study is to model the electrical response of gold plated copper electrical contacts exposed to a mixed flowing gas stream consisting of air containing 10 ppb H{sub 2}S at 30 C and a relative humidity of 70%. This environment accelerates the attack normally observed in a light industrial environment (essentially a simplified version of the Battelle Class 2 environment). Corrosion rates were quantified by measuring the corrosion site density, size distribution, and the macroscopic electrical resistance of the aged surface as a function of exposure time. A pore corrosion numerical model was used to predict bothmore » the growth of copper sulfide corrosion product which blooms through defects in the gold layer and the resulting electrical contact resistance of the aged surface. Assumptions about the distribution of defects in the noble metal plating and the mechanism for how corrosion blooms affect electrical contact resistance were needed to complete the numerical model. Comparisons are made to the experimentally observed number density of corrosion sites, the size distribution of corrosion product blooms, and the cumulative probability distribution of the electrical contact resistance. Experimentally, the bloom site density increases as a function of time, whereas the bloom size distribution remains relatively independent of time. These two effects are included in the numerical model by adding a corrosion initiation probability proportional to the surface area along with a probability for bloom-growth extinction proportional to the corrosion product bloom volume. The cumulative probability distribution of electrical resistance becomes skewed as exposure time increases. While the electrical contact resistance increases as a function of time for a fraction of the bloom population, the median value remains relatively unchanged. In order to model this behavior, the resistance calculated for large blooms has been weighted more heavily.« less

  8. Development of selective solar absorbers on the basis of aluminum roll-bond heat exchangers

    NASA Astrophysics Data System (ADS)

    Moeller, M.

    1981-11-01

    A deposition technique comparable to two-stage anodizing and especially suited for solar absorber panels, using roll-bond Al 99.5 and AlMnZr alloys as a substrate, was developed. The coating is of the nickel structure filter type and provides average solar absorptivity values of 94% and thermal emission values of 14%. The setup of a production plant capable of coating surfaces up to 2 sq m is described as well as the development of corrosion resistent hermetically sealed collectors. By means of an appropriate surface treatment the same corrosion resistance was achieved for absorbers mounted in ventilated collectors.

  9. 46 CFR 111.01-11 - Corrosion-resistant parts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Corrosion-resistant parts. 111.01-11 Section 111.01-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-11 Corrosion-resistant parts. Each enclosure and part of electric...

  10. 46 CFR 111.01-11 - Corrosion-resistant parts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Corrosion-resistant parts. 111.01-11 Section 111.01-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-11 Corrosion-resistant parts. Each enclosure and part of electric...

  11. 46 CFR 111.01-11 - Corrosion-resistant parts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Corrosion-resistant parts. 111.01-11 Section 111.01-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-11 Corrosion-resistant parts. Each enclosure and part of electric...

  12. 46 CFR 111.01-11 - Corrosion-resistant parts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Corrosion-resistant parts. 111.01-11 Section 111.01-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-11 Corrosion-resistant parts. Each enclosure and part of electric...

  13. 49 CFR 179.201-5 - Postweld heat treatment and corrosion resistance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Postweld heat treatment and corrosion resistance....201-5 Postweld heat treatment and corrosion resistance. (a) Tanks and attachments welded directly thereto must be postweld heat treated as a unit at the proper temperature except as indicated below. Tanks...

  14. 46 CFR 111.01-11 - Corrosion-resistant parts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Corrosion-resistant parts. 111.01-11 Section 111.01-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-11 Corrosion-resistant parts. Each enclosure and part of electric...

  15. 77 FR 14501 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-12

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant... the preliminary results of the antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea).\\1\\ This review covers eight...

  16. 77 FR 54891 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-06

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant...) is conducting the 18th administrative review of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea \\1\\ (Korea). This review covers seven...

  17. 78 FR 55057 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-09

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon... Department) is conducting an administrative review of the antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea), covering the period [[Page 55058...

  18. 76 FR 55004 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant...) is conducting the seventeenth administrative review of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea \\1\\ (Korea). This review covers eight...

  19. Electrochemical study of Type 304 and 316L stainless steels in simulated body fluids and cell cultures.

    PubMed

    Tang, Yee-Chin; Katsuma, Shoji; Fujimoto, Shinji; Hiromoto, Sachiko

    2006-11-01

    The electrochemical corrosion behaviour of Type 304 and 316L stainless steels was studied in Hanks' solution, Eagle's minimum essential medium (MEM), serum containing medium (MEM with 10% of fetal bovine serum) without cells, and serum containing medium with cells over a 1-week period. Polarization resistance measurements indicated that the stainless steels were resistant to Hanks' and MEM solutions. Type 304 was more susceptible to pitting corrosion than Type 316L in Hanks' and MEM solutions. The uniform corrosion resistance of stainless steels, determined by R(p), was lower in culturing medium than in Hanks' and MEM. The low corrosion resistance was due to surface passive film with less protective to reveal high anodic dissolution rate. When cells were present, the initial corrosion resistance was low, but gradually increased after 3 days, consistent with the trend of cell coverage. The presence of cells was found to suppress the cathodic reaction, that is, oxygen reduction, and increase the uniform corrosion resistance as a consequence. On the other hand, both Type 304 and 316L stainless steels became more susceptible to pitting corrosion when they were covered with cells.

  20. A technique for predicting steel corrosion resistance

    NASA Astrophysics Data System (ADS)

    Novikov, V. F.; Sokolov, R. A.; Neradovskiy, D. F.; Muratov, K. R.

    2018-01-01

    Research works were carried out to develop a technique with the aim to increase the lifetime of steel items used in corrosive media. The possibility to monitor corrosion parameters of steel samples is analyzed on the basis of magnetic properties obtained by means of a magnetic structuroscope DIUS-1.15M designed by the Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences (IMP UB RAS).

  1. Demonstration of Corrosion-Resistant Hybrid Composite Bridge Beams for Structural Applications

    DTIC Science & Technology

    2016-09-01

    result of corrosion of the steel support structures or the reinforcing bar in the concrete. The application of corrosion-resistant technology can...demonstrated and validated a corrosion-resistant hybrid-composite beam (HCB) for the reconstruction of a one span of a traditional steel and...concrete bridge at Fort Knox, Kentucky. The HCBs were installed on half of the bridge, and conventional steel beams were installed on the other half

  2. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    DOEpatents

    Park, Jong-Hee; Natesan, Krishnamurti; Rink, David L.

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  3. NON-CORROSIVE REACTOR FUEL SYSTEM

    DOEpatents

    Herrick, C.C.

    1962-08-14

    A non-corrosive nuclear reactor fuel system was developed utilizing a molten plutonium-- iron alloy fuel having about 2 at.% carbon and contained in a tantalum vessel. This carbon reacts with the interior surface of the tantalum vessel to form a plutonium resistant self-healing tantalum carbide film. (AEC)

  4. Effect of modification of oxide layer on NiTi stent corrosion resistance.

    PubMed

    Trépanier, C; Tabrizian, M; Yahia, L H; Bilodeau, L; Piron, D L

    1998-01-01

    Because of its good radiopacity, superelasticity, and shape memory properties, nickel-titanium (NiTi) is a potential material for fabrication of stents because these properties can facilitate their implantation and precise positioning. However, in vitro studies of NiTi alloys report the dependence of alloy biocompatibility and corrosion behavior on surface conditions. Surface oxidation seems to be very promising for improving the corrosion resistance and biocompatibility of NiTi. In this work, we studied the effect on corrosion resistance and surface characteristics of electropolishing, heat treatment, and nitric acid passivation of NiTi stents. Characterization techniques such as potentiodynamic polarization tests, scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy were used to relate corrosion behavior to surface characteristics and surface treatments. Results show that all of these surface treatments improve the corrosion resistance of the alloy. This improvement is attributed to the plastically deformed native oxide layer removal and replacement by a newly grown, more uniform one. The uniformity of the oxide layer, rather than its thickness and composition, seems to be the predominant factor to explain the corrosion resistance improvement.

  5. Effects of Sn and Sb on the corrosion resistance of AH 32 steel in a cargo oil tank environment

    NASA Astrophysics Data System (ADS)

    Ahn, SooHoon; Park, Kyung Jin; Oh, KkochNim; Hwang, SungDoo; Park, ByungJoon; Kwon, HyukSang; Shon, MinYoung

    2015-09-01

    Effects of the alloying elements, Sn and Sb, on the corrosion resistance of modified AH 32 steel for the cargo oil tanks (COT) were examined using an electrochemical test and weight loss measurement. All experiments were carried out in acidic chloride solution (0.14 M HCl and 10 wt% NaCl, pH 0.85) at 30 °C, simulating the inner bottom plate of COT. It was clearly found that the small amount addition of Sn and Sb improved the corrosion resistance of modified AH 32 steel, which is confirmed by the higher polarization resistance of AH 32 steel modified with Sn and Sb addition compared with that of the base steel. X-ray photoelectron spectroscopy analysis of the corroded surface after immersion of 72 h presented that the AH 32 steel modified with Sn and Sb addition created the protective corrosion products including SnO2 and Sb2O5. These oxides act as high corrosion inhibitor to anodic corrosion reaction, and hence leading to the improvement in the corrosion resistance of the modified AH 32 steels.

  6. Pulsed Laser Deposition Processing of Improved Titanium Nitride Coatings for Implant Applications

    NASA Astrophysics Data System (ADS)

    Haywood, Talisha M.

    Recently surface coating technology has attracted considerable attention of researchers to develop novel coatings with enhanced functional properties such as hardness, biocompatibility, wear and corrosion resistance for medical devices and surgical tools. The materials currently being used for surgical implants include predominantly stainless steel (316L), cobalt chromium (Co-Cr), titanium and its alloys. Some of the limitations of these implants include improper mechanical properties, corrosion resistance, cytotoxicity and bonding with bone. One of the ways to improve the performance and biocompatibility of these implants is to coat their surfaces with biocompatible materials. Among the various coating materials, titanium nitride (TiN) shows excellent mechanical properties, corrosion resistance and low cytotoxicity. In the present work, a systematic study of pulsed laser ablation processing of TiN coatings was conducted. TiN thin film coatings were grown on commercially pure titanium (Ti) and stainless steel (316L) substrates at different substrate temperatures and different nitrogen partial pressures using the pulsed laser deposition (PLD) technique. Microstructural, surface, mechanical, chemical, corrosion and biological analysis techniques were applied to characterize the TiN thin film coatings. The PLD processed TiN thin film coatings showed improvements in mechanical strength, corrosion resistance and biocompatibility when compared to the bare substrates. The enhanced performance properties of the TiN thin film coatings were a result of the changing and varying of the deposition parameters.

  7. Structure-composition-property relationships in 5xxx series aluminum alloys

    NASA Astrophysics Data System (ADS)

    Unocic, Kinga A.

    Al-Mg alloys are well suited for marine applications due to their low density, ease of fabrication, structural durability, and most notably resistance to corrosion. The purpose of this study is to investigate the effects of alloying additions, mechanical processing and heat treatments on the development of grain boundary phases that have an effect on intergranular corrosion (IGC). Cu, Zn, and Si modified compositions of AA5083 were produced that were subjected to a low and high degree of cold work and various heat treatments. ASTM G67 (NAMLT) intergranular corrosion testing and detailed microstructural characterization for various alloys was carried out. An optimal composition and processing condition that yielded the best intergranular corrosion resistant material was identified based on the ASTM G67 test screening. Further, the outstanding modified AA5083 was selected for further microstructural analysis. This particular alloy with has a magnesium level high enough to make it susceptible to intergranular corrosion is very resistant to IGC. It was found that development of the appropriate sub-structure with some Cu, Si and Zn resulted in a material very resistant to IGC. Formation of many sinks, provided by sub-boundaries, within microstructure is very beneficial since it produces a relatively uniform distribution of Mg in the grain interiors, and this can suppress sensitization of this alloy very successfully. This is a very promising rote for the production of high-strength, and corrosion resistant aluminum alloys. Additionally in this study, TEM sample preparation become very crucial step in grain boundary phase investigation. Focus Ion Beam (FIB) milling was used as a primary TEM sample preparation technique because it enables to extract the samples from desired and very specific locations without dissolving grain boundary phases as it was in conventional electropolishing method. However, other issues specifically relevant to FIB milling of aluminum alloys related to Ga accumulation were discovered, that produce significant microstructural artifacts. It is well known that liquid gallium can cause Liquid Metal Embitterment (LME) aluminum alloys, and gallium readily penetrates aluminum grain boundaries. Low energy Ar ion nanomilling is potentially quite effective at removing gallium from the external and internal surfaces of aluminum thin foils, but can still leave persistent artifacts. Al-Mg alloys can be also susceptible to localized corrosion such as pitting corrosion in the presence of chloride ions. In this study the phases responsible for this type of corrosion were identified. ASSET (ASTM G66) test was used to determine the influence of heat-treatment on pitting corrosion on various modified AA5083 alloys. Additionally, potentiodynamic polarization as well as potentiostatic measurements in conjunction with SEM analysis were carried out to obtain pitting potential (Epit) and to determine the location of metastable pit initiation, respectively.

  8. 77 FR 16810 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time Limit for Preliminary Results of... Register the countervailing duty order on corrosion-resistant carbon steel flat products (CORE) from Korea...

  9. 75 FR 18153 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time Limit for Preliminary Results of... countervailing duty order on corrosion-resistant carbon steel flat products (CORE) from Korea. See Countervailing...

  10. 76 FR 20954 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time Limit for Preliminary Results of... Register the countervailing duty order on corrosion-resistant carbon steel flat products (CORE) from Korea...

  11. Cr-Free Metallic-Ceramic Coatings

    DTIC Science & Technology

    2014-11-01

    Comparable to Aluminum-Chromate/ Phosphate Humidity Resistance Galvanic Corrosion Resistance Nov. 2014 ASETSDefense 2014, Fort Myer, VA...Aluminum-Silicate Comparable to Aluminum-Chromate/ Phosphate  Humidity, Galvanic Corrosion , Heat/Salt Resistance  Adhesion & Compatibility...WP-TR-2007-4069, Sept. 2006 Sealed Aluminum-Silicate Not Comparable to Sealed Aluminum-Chromate/ Phosphate in PEWG Evaluation  Corrosion

  12. 76 FR 4291 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon... Commerce (the Department) initiated an administrative review of the countervailing duty order on corrosion- resistant carbon steel flat products from the Republic of Korea covering the period January 1, 2009, through...

  13. 76 FR 77775 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-580-818] Corrosion-Resistant Carbon... results of the administrative review of the countervailing duty order on corrosion-resistant carbon steel flat products from the Republic of Korea covering the period January 1, 2009, through December 31, 2009...

  14. 76 FR 69703 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon... administrative review of the antidumping duty order on corrosion-resistant carbon steel flat products from Korea, covering the period August 1, 2009, to July 31, 2010. See Initiation of Antidumping and Countervailing Duty...

  15. 78 FR 59651 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant... duty order on certain corrosion-resistant carbon steel flat products (``CORE'') from the Republic of... covering the period of review (``POR'') of August 1, 2006 through July 31, 2007, with respect to the...

  16. 77 FR 25405 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-30

    ... antidumping duty order on corrosion-resistant carbon steel flat products from the Republic of Korea, covering... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time Limit for the Preliminary Results of...

  17. 78 FR 59652 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Certain Corrosion-Resistant... corrosion-resistant carbon steel flat products (``CORE'') from the Republic of Korea (``Korea''), pursuant... administrative review of the antidumping duty order on CORE from Korea covering the period of review (``POR'') of...

  18. 75 FR 25841 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ... antidumping duty order on corrosion-resistant carbon steel flat products from the Republic of Korea, covering... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time Limits for the Preliminary Results of...

  19. 76 FR 21332 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ... antidumping duty order on corrosion-resistant carbon steel flat products from the Republic of Korea, covering... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time Limits for the Preliminary Results of...

  20. 78 FR 16247 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea; Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon... preliminary results of the administrative review of the antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea).\\1\\ This review covers seven manufacturers...

  1. 75 FR 77615 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-13

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-580-816] Corrosion-Resistant Carbon... administrative review of the antidumping duty order on corrosion-resistant carbon steel flat products from Korea, covering the period August 1, 2008, to July 31, 2009. See Initiation of Antidumping and Countervailing Duty...

  2. Repeated Impact Method and Devices to Simulate the Impact Fatigue Property of Drillstring

    NASA Astrophysics Data System (ADS)

    Lin, Y. H.; Li, B.; Pan, J.; Li, Q.; Liu, W. Y.; Pan, Y.

    2017-05-01

    It is well known that drillstring failures are a pendent problem in drilling engineering, because of the fatigue accumulation caused by the low amplitude-repeated impact. In order to reveal the effect of low amplitude-repeated impact on the failure mechanism of the drillstring, a repeated impact method and instrument have been developed based on the Charpy impact method, by which a series of tests have been performed in the condition of non-corrosive medium and with H2S environment respective. Test results of non-corrosive medium environment indicates that, with the increase of single impact energy, the low amplitude-repeated impact resistance of drillstring decreases significantly; For H2S corrosion environment, the low amplitude-repeated impact resistances with H2S is much lower than that without H2S corrosion, and high strength material such as V-150 drillstring is more sensitive to H2S corrosion media. Furthermore, based on the experiment data, the accumulation fatigue model to predict the service life of the drillstring is developed, which could be used to predict the fatigue life. Research fruits are very vital to select a suitable rotational speed for drilling job and drillstring design.

  3. Environmentally Preferable Coatings for Structural Steel Project

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L. (Editor)

    2014-01-01

    The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described a the "launch support and infrastructure modernization program" in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the objective of this project is to determine the feasibility of environmentally friendly corrosion resistant coatings for launch facilities and ground support equipment. The focus of the project is corrosion resistance and survivability with the goal to reduce the amount of maintenance required to preserve the performance of launch facilities while reducing mission risk. Number of facilities/structures with metallic structural and non-structural components in a highly corrosive environment. Metals require periodic maintenance activity to guard against the insidious effects of corrosion and thus ensure that structures meet or exceed design or performance life. The standard practice for protecting metallic substrates in atmospheric environments is the application of corrosion protective coating system.

  4. Fe-Based Amorphous Coatings on AISI 4130 Structural Steel for Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Katakam, Shravana; Santhanakrishnan, S.; Dahotre, Narendra B.

    2012-06-01

    The current study focuses on synthesizing a novel functional coating for corrosion resistance applications, via laser surface alloying. The iron-based (Fe48Cr15Mo14Y2C15B) amorphous precursor powder is used for laser surface alloying on AISI 4130 steel substrate, with a continuous wave ytterbium Nd-YAG fiber laser. The corrosion resistance of the coatings is evaluated for different processing conditions. The microstructural evolution and the response of the microstructure to the corrosive environment is studied using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Microstructural studies indicate the presence of face-centered cubic Fe-based dendrites intermixed within an amorphous matrix along with fine crystalline precipitates. The corrosion resistance of the coatings decrease with an increase in laser energy density, which is attributed to the precipitation and growth of chromium carbide. The enhanced corrosion resistance of the coatings processed with low energy density is attributed to the self-healing mechanism of this amorphous system.

  5. Effect of Sn4+ Additives on the Microstructure and Corrosion Resistance of Anodic Coating Formed on AZ31 Magnesium Alloy in Alkaline Solution

    NASA Astrophysics Data System (ADS)

    Salman, S. A.; Kuroda, K.; Saito, N.; Okido, M.

    Magnesium is the lightest structural metal with high specific strength and good mechanical properties. However, poor corrosion resistance limits its widespread use in many applications. Magnesium is usually treated with Chromate conversion coatings. However, due to changing environmental regulations and pollution prevention requirements, a significant push exists to find new, alternative for poisonous Cr6+. Therefore, we aim to improve corrosion resistance of anodic coatings on AZ31 alloys using low cost non-chromate electrolyte. Anodizing was carried out in alkaline solutions with tin additives. The effect of tin additives on the coating film was characterized by SEM and XRD. The corrosion resistance was evaluated using anodic and cathodic polarizations and electrochemical impedance spectroscopy (EIS). Corrosion resistance property was improved with tin additives and the best anti-corrosion property was obtained with addition of 0.03 M Na2SnO3.3H2O to anodizing solution.

  6. The Enhancement of Mg Corrosion Resistance by Alloying Mn and Laser-Melting

    PubMed Central

    Yang, Youwen; Wu, Ping; Wang, Qiyuan; Wu, Hong; Liu, Yong; Deng, Youwen; Zhou, Yuanzhuo; Shuai, Cijun

    2016-01-01

    Mg has been considered a promising biomaterial for bone implants. However, the poor corrosion resistance has become its main undesirable property. In this study, both alloying Mn and laser-melting were applied to enhance the Mg corrosion resistance. The corrosion resistance, mechanical properties, and microstructure of rapid laser-melted Mg-xMn (x = 0–3 wt %) alloys were investigated. The alloys were composed of dendrite grains, and the grains size decreased with increasing Mn. Moreover, Mn could dissolve and induce the crystal lattice distortion of the Mg matrix during the solidification process. Mn ranging from 0–2 wt % dissolved completely due to rapid laser solidification. As Mn contents further increased up to 3 wt %, a small amount of Mn was left undissolved. The compressive strength of Mg-Mn alloys increased first (up to 2 wt %) and then decreased with increasing Mn, while the hardness increased continuously. The refinement of grains and the increase in corrosion potential both made contributions to the enhancement of Mg corrosion resistance. PMID:28773342

  7. The Effect of Boronizing on Metallic Alloys for Automotive Applications

    NASA Astrophysics Data System (ADS)

    Petrova, Roumiana S.; Suwattananont, Naruemon; Samardzic, Veljko

    2008-06-01

    In this study the wear resistance, corrosion resistance, and oxidation resistance of boronized metallic alloys were investigated. Thermochemical treatment was performed by powder pack boronizing process at temperature 850-950 °C for 4 h. Saw-tooth morphology and smooth interface microstructures were observed with an optical microscope; microhardness was measured across the coating depth. The phases present in the boron coatings depend on the substrate material. High-temperature oxidation resistance was investigated and it was found that boron coating on ferrous alloys can resist temperatures up to 800 °C. The corrosion resistance of the boronized samples was improved and the corrosion rate was calculated for boronized and plain specimens. Wear testing was conducted by following the procedures of ASTM G99, ASTM D2526, and ASTM D4060. The obtained experimental results revealed that boronizing significantly improves the wear-resistance, corrosion-resistance, and oxidation resistance of metallic alloys.

  8. Corrosion and Wear Response of Oxide-Reinforced Nickel Composite Coatings

    NASA Astrophysics Data System (ADS)

    Tirlapur, Pradeep; Muniprakash, M.; Srivastava, Meenu

    2016-07-01

    Various grades of fuels are used in automobiles, as a result the engine components are continuously subjected to simultaneous action of corrosion and wear. Ni-SiC composite coating is the most widely investigated and commercialized wear-resistant coating in the automotive industry. However, this coating cannot be used at temperatures above 450 °C due to the tendency of SiC to react with Ni and form brittle silicides. An alternate approach is to use oxide-reinforced coatings. In the present study, zirconia, ZrO2 and, yttria-stabilized zirconia, YSZ-reinforced Ni composite coatings have been developed by electrodeposition method. It was observed from the microhardness studies that there is no significant difference in the values for Ni-SiC and Ni-ZrO2 coatings. The corrosion behavior was evaluated using polarization and electrochemical impedance studies. The studies showed that oxide particle-reinforced Ni coatings possessed better corrosion resistance due to their lower corrosion current density, I corr. Tribo-corrosion studies were carried out to understand the synergistic effect of wear and corrosion on the performance of Ni-based composite coatings in 0.5 M Na2SO4. Among various composite coatings, Ni-YSZ exhibited less material loss thereby showing better tribo-corrosion behavior.

  9. Ion implantation of highly corrosive electrolyte battery components

    DOEpatents

    Muller, R.H.; Zhang, S.

    1997-01-14

    A method of producing corrosion resistant electrodes and other surfaces in corrosive batteries using ion implantation is described. Solid electrically conductive material is used as the ion implantation source. Battery electrode grids, especially anode grids, can be produced with greatly increased corrosion resistance for use in lead acid, molten salt, and sodium sulfur. 6 figs.

  10. Ion implantation of highly corrosive electrolyte battery components

    DOEpatents

    Muller, Rolf H.; Zhang, Shengtao

    1997-01-01

    A method of producing corrosion resistant electrodes and other surfaces in corrosive batteries using ion implantation is described. Solid electrically conductive material is used as the ion implantation source. Battery electrode grids, especially anode grids, can be produced with greatly increased corrosion resistance for use in lead acid, molten salt, end sodium sulfur.

  11. Corrosion Studies of Wrought and Cast NASA-23 Alloy

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1997-01-01

    Corrosion studies were carried out for wrought and cast NASA-23 alloy using electrochemical methods. The scanning reference electrode technique (SRET), the polarization resistance technique (PR), and the electrochemical impedance spectroscopy (EIS) were employed. These studies corroborate the findings of stress corrosion studies performed earlier, in that the material is highly resistant to corrosion.

  12. Hot Corrosion Resistance and Mechanical Behavior of Atmospheric Plasma Sprayed Conventional and Nanostructured Zirconia Coatings

    NASA Astrophysics Data System (ADS)

    Saremi, Mohsen; Keyvani, Ahmad; Heydarzadeh Sohi, Mahmoud

    Conventional and nanostructured zirconia coatings were deposited on In-738 Ni super alloy by atmospheric plasma spray technique. The hot corrosion resistance of the coatings was measured at 1050°C using an atmospheric electrical furnace and a fused mixture of vanadium pent oxide and sodium sulfate respectively. According to the experimental results nanostructured coatings showed a better hot corrosion resistance than conventional ones. The improved hot corrosion resistance could be explained by the change of structure to a dense and more packed structure in the nanocoating. The evaluation of mechanical properties by nano indentation method showed the hardness (H) and elastic modulus (E) of the YSZ coating increased substantially after hot corrosion.

  13. Corrosion resistant storage container for radioactive material

    DOEpatents

    Schweitzer, D.G.; Davis, M.S.

    1984-08-30

    A corrosion resistant long-term storage container for isolating high-level radioactive waste material in a repository is claimed. The container is formed of a plurality of sealed corrosion resistant canisters of different relative sizes, with the smaller canisters housed within the larger canisters, and with spacer means disposed between juxtaposed pairs of canisters to maintain a predetermined spacing between each of the canisters. The combination of the plural surfaces of the canisters and the associated spacer means is effective to make the container capable of resisting corrosion, and thereby of preventing waste material from leaking from the innermost canister into the ambient atmosphere.

  14. Corrosion resistant storage container for radioactive material

    DOEpatents

    Schweitzer, Donald G.; Davis, Mary S.

    1990-01-01

    A corrosion resistant long-term storage container for isolating radioactive waste material in a repository. The container is formed of a plurality of sealed corrosion resistant canisters of different relative sizes, with the smaller canisters housed within the larger canisters, and with spacer means disposed between judxtaposed pairs of canisters to maintain a predetermined spacing between each of the canisters. The combination of the plural surfaces of the canisters and the associated spacer means is effective to make the container capable of resisting corrosion, and thereby of preventing waste material from leaking from the innermost canister into the ambient atmosphere.

  15. [Study on corrosion resistance of three non-noble porcelain alloys].

    PubMed

    Wu, Zhikai; Xu, Sheng; Li, Wei; Teng, Jin; Li, Ning

    2011-10-01

    To study the electrochemical corrosion behavior of Co-Cr, Ni-Cr and Ni-Cr-Be based porcelain alloys in NaCl solution. Five samples of each alloy were made respectively, electric polarization curve of each alloy was obtained using potentiodynamic polarization technique. Self-corrosion potential (E(corr)), self-corrosion current density (I(corr), passive region and transpassivation potential were tested. Microstructure and constituent was examined using scanning electron microscopy and energy dispersive spectroscopy. Co-Cr alloy possessed the most desirable corrosion resistance because of its integrated, homogeneous and compact passive film. The poor compactness of Ni-Cr alloy's passive film decreased its corrosion resistance. Ni-Cr-Be alloy exhibited the worst corrosion resistance due to the Cr and Mo depleted Ni-Be eutectic phases in the alloy. Taking biological security into consideration, it is necessary to avoid the application of porcelain alloys with Be element. Co-Cr alloy with better biocompatibility possesses much broader prospect in the field of dental restoration.

  16. Microstructure and Corrosion Resistance of Laser-Welded Crossed Nitinol Wires.

    PubMed

    Dong, Peng; Yao, Runhua; Yan, Zheng; Yan, Zhifeng; Wang, Wenxian; He, Xiuli; Zhou, Jun

    2018-05-18

    Laser welding has been considered to be one of the most promising joining processes for Nitinol medical device manufacturing. Presently, there is still a limited understanding about how laser welding affects the microstructure and the resultant corrosion behaviors. This work aimed to reveal the microstructural factors that influence the corrosion resistance of laser-welded crossed Nitinol joints. The microstructures within various zones of the joints were characterized by using transmission electron microscopy (TEM), and the corrosion behaviors of the joints in 0.9% NaCl and Hank's solutions were studied. The base metal exhibits a single austenite (B2) phase and the highest corrosion resistance. The phase constituent of the fusion zone is the coexistence of the B2 matrix and some precipitates (T₂Ni, TiNi 3, and Ti₃Ni₄ particles), resulting in a slight decrease in corrosion resistance. The heat affected zone (HAZ) shows the austenite matrix but with the precipitation of R-phase, which considerably reduces the corrosion potential, making it the weakest zone.

  17. In vitro evaluation of the electrochemical behaviour of stainless steel and Ni-Ti orthodontic archwires at different temperatures.

    PubMed

    Pakshir, M; Bagheri, T; Kazemi, M R

    2013-08-01

    The aim of this study was to compare the electrochemical corrosion behaviour of stainless steel (SS) and nickel-titanium (Ni-Ti) orthodontic archwires in Ringer's solution at temperatures ranging from 15 to 55°C by using linear sweep voltametry and electrochemical impedance spectroscopy. Polarization curves show that the corrosion current density of SS is greater than that of Ni-Ti alloy. Since the corrosion current density is directly proportional to the corrosion rate, a great corrosion current density shows a lower resistance against corrosion. Therefore, in comparison with SS, Ni-Ti alloys have a lower corrosion rate. Results show that the temperature of the solution affects the corrosion rates of the alloys. As the temperature increases, the corrosion resistance of both of the alloys decreases, although these variations were not so large. Impedance measurements show that the electrochemical behaviour of Ni-Ti exhibits higher polarization resistance and lower capacitance, which means that passive film formed on this alloy is more homogeneous and thicker in comparison with SS. Results also show that polarization resistance of both alloys decreases slowly with increases in the temperature of the solution.

  18. Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments

    NASA Astrophysics Data System (ADS)

    Hannigan, K.; Reid, M.; Collins, M. N.; Dalton, E.; Xu, C.; Wright, B.; Demirkan, K.; Opila, R. L.; Reents, W. D.; Franey, J. P.; Fleming, D. A.; Punch, J.

    2012-03-01

    Recently, the corrosion resistance of printed wiring board (PWB) finishes has generated considerable interest due to field failures observed in various parts of the world. This study investigates the corrosion issues associated with the different lead-free PWB surface finishes. Corrosion products on various PWB surface finishes generated in mixed flowing gas (MFG) environments were studied, and analysis techniques such as scanning electron microscopy, energy-dispersive x-ray, x-ray diffraction, focused ion beam, and scanning Auger microscopy were used to quantify the corrosion layer thickness and determine the composition of corrosion products. The corrosion on organic solderability preservative samples shows similar corrosion products to bare copper and is mainly due to direct attack of copper traces by corrosive gases. The corrosion on electroless nickel immersion gold occurs primarily through the porosity in the film and is accelerated by the galvanic potential between gold and copper; similar results were observed on immersion silver. Immersion tin shows excellent corrosion resistance due to its inherent corrosion resistance in the MFG environment as well as the opposite galvanic potential between tin and copper compared with gold or silver and copper.

  19. Relationship Between pH and Electrochemical Corrosion Behavior of Thermal-Sprayed Ni-Al-Coated Q235 Steel in Simulated Soil Solutions

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Wu, Xin-qiang; Ke, Wei; Xu, Song; Feng, Bing; Hu, Bo-tao

    2017-09-01

    Electrochemical corrosion behavior of a thermal-sprayed Ni-Al-coated Q235 steel was investigated in the simulated soil solutions at different pH values using measurements of potentiodynamic polarization curves and electrochemical impedance spectroscopy as well as surface analyses including x-ray diffraction analysis, scanning electron microscope equipped with an energy-dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The results showed that the corrosion resistance of the Ni-Al-coated Q235 steel was dependent on the pH of the test solution. From pH = 3.53 to pH = 4.79, the corrosion resistance of the coated steel increased rapidly. In the pH range from 4.79 to 12.26, the corrosion resistance exhibited no significant change. At pH 13.25, the corrosion resistance of the sample was found to decrease. The calculated corrosion rate of Ni-Al-coated Q235 steel was lower than that of the uncoated Q235 steel and galvanized steel in all the test solutions. Over a wide range of pH values, the Ni-Al-coated Q235 steel exhibited extremely good corrosion resistance. The experimental data together with the potential-pH diagrams provided a basis for a detailed discussion of the related corrosion mechanisms of the coated steel.

  20. Effects of laser polishing on surface microstructure and corrosion resistance of additive manufactured CoCr alloys

    NASA Astrophysics Data System (ADS)

    Wang, W. J.; Yung, K. C.; Choy, H. S.; Xiao, T. Y.; Cai, Z. X.

    2018-06-01

    Laser polishing of 3D printed metal components has drawn great interest in view of its potential applications in the dental implant industries. In this study, corrosion resistance, surface composition and crystalline structure of CoCr alloys were investigated. The corrosion resistance, micromorphology, composition, phase transformations and crystalline structures of samples were characterized using an electrochemical analyzer, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The results indicate that high laser powers and low object distances within a certain range can facilitate the formation of complex oxide films, which exhibits high corrosion resistance. Further, object distances have a significant influence on cooling rates during the solidification of the melt pool in laser polishing, and fast cooling generates vast amounts of vacancies and defects, which result in the crystalline phase transformation from γ to ε. Consequently, the formed oxides play an important role in corrosion resistance on the outer layer, and inner layer with γ phase also helps keep the CoCr alloys in a stable structure with high resistant to corrosion. The two process parameters in laser polishing, laser power and object distances, are demonstrated as being important for controlling the surface microstructures and corrosion resistance of the additive manufactured CoCr alloy components.

  1. Materials Selection for Superheater Tubes in Municipal Solid Waste Incineration Plants

    NASA Astrophysics Data System (ADS)

    Morales, M.; Chimenos, J. M.; Fernández, A. I.; Segarra, M.

    2014-09-01

    Corrosion reduces the lifetime of municipal solid waste incineration (MSWI) superheater tubes more than any other cause. It can be minimized by the careful selection of those materials that are most resistant to corrosion under operating conditions. Since thousands of different materials are already known and many more are developed every year, here the selection methodology developed by Prof. Ashby of the University of Cambridge was used to evaluate the performance of different materials to be used as MSWI superheater tubes. The proposed materials can operate at steam pressures and temperatures over 40 bars and 400 °C, respectively. Two case studies are presented: one makes a balanced selection between mechanical properties and cost per thermal unit; and the other focuses on increasing tube lifetime. The balanced selection showed that AISI 410 martensitic stainless steel (wrought, hard tempered) is the best candidate with a good combination of corrosion resistance, a relatively low price (0.83-0.92 €/kg) and a good thermal conductivity (23-27 W/m K). Meanwhile, Nitronic 50/XM-19 stainless steel is the most promising candidate for long-term selection, as it presents high corrosion resistance with a relatively low price (4.86-5.14 €/kg) compared to Ni-alloys.

  2. High-temperature corrosion of metals in the salt and metallic melts containing rare earths

    NASA Astrophysics Data System (ADS)

    Karpov, V. V.; Abramov, A. V.; Zhilyakov, A. Yu.; Belikov, S. V.; Volkovich, V. A.; Polovov, I. B.; Rebrin, O. I.

    2016-09-01

    A complex of independent methods was employed to study the corrosion resistance of molybdenum, zirconium, tantalum and tungsten in chloride, chloride-fluoride and fluoride-oxide melts based on LiCl, CaCl2, NaCl- KCl, LiF, and containing rare earths. Tests were conducted for 30 h at 750-1050 °C. The metals showed excellent corrosion resistance in fused chlorides (the corrosion rates were below 0.0005 g/(m2 h). Despite the presence of chemically active fluoride ions in the chloride-fluoride melts, the metals studied also showed very low corrosion rates, except molybdenum, for which the rate of corrosion was 0,8 g/(m2 h). The corrosion resistance of tantalum was considerably reduced in the fluoride-oxide melts; the corrosion rate was over 1 g/(m2 h) corresponding to the 8-th grade of stability and placing tantalum to the group of "low stability" materials.

  3. Improvement of the linear polarization resistance method for testing steel corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    Faritov, A. T.; Rozhdestvenskii, Yu. G.; Yamshchikova, S. A.; Minnikhanova, E. R.; Tyusenkov, A. S.

    2016-11-01

    The linear polarization resistance method is used to improve the technique of corrosion control in liquid conducting according to GOST 9.514-99 (General Corrosion and Aging Protection System. Corrosion Inhibitors for Metals in Water Systems. Electrochemical Method of Determining the Protective Ability). Corrosion monitoring is shown to be performed by electronic devices with real-time data transfer to industrial controllers and SCADA systems.

  4. Characterization and Properties of Micro-arc Composite Ceramic Coatings on Magnesium Alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Long; Jiang, Bailing; Ge, Yanfeng

    2013-05-21

    Magnesium alloys are of growing interest for many industrial applications due to their favorable strength-to-weight ratio and excellent cast ability. However, one of the limiting factors in the use of magnesium on production vehicles is its poor corrosion resistance. Micro-arc Composite Ceramic (MCC) coatings on AZ91D magnesium alloys were prepared in combination with Micro-arc Oxidation (MAO) and electrophoresis technologies. The microstructure, corrosion resistance, abrasion resistance, stone impact resistance, thermal shock resistance and adhesion of MCC coating were studied, respectively. The surface and cross-section morphologies of MAO and MCC coating showed that the outer organic coating filled the holes on themore » surface of the MAO coating. It acted as a shelter on the MAO coating surface when the MCC coatings were exposed to corrosive environments. The corrosion resistance of the MCC coating was characterized by a copper-accelerated acetic acid salt spray test. The testing results showed that the creep back from scribe lines was less than 1mm and completely fit the evaluation standard. The composite structure of the MCC coating vastly improved the corrosion resistance of Mg alloys. According to testing standards, the resistance to abrasion, stone impact resistance, thermal shock resistance and adhesion of MCC coatings completely met the evaluation standard requirements. The MCC coated AZ91D magnesium alloys possessed excellent properties; this is a promising corrosion and wear resistance surface treatment technology on magnesium alloys for production vehicles.« less

  5. Improvement of bio-corrosion resistance for Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid by annealing within supercooled liquid region.

    PubMed

    Huang, C H; Lai, J J; Wei, T Y; Chen, Y H; Wang, X; Kuan, S Y; Huang, J C

    2015-01-01

    The effects of the nanocrystalline phases on the bio-corrosion behavior of highly bio-friendly Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid were investigated, and the findings are compared with our previous observations from the Zr53Cu30Ni9Al8 metallic glasses. The Ti42Zr40Si15Ta3 metallic glasses were annealed at temperatures above the glass transition temperature, Tg, with different time periods to result in different degrees of α-Ti nano-phases in the amorphous matrix. The nanocrystallized Ti42Zr40Si15Ta3 metallic glasses containing corrosion resistant α-Ti phases exhibited more promising bio-corrosion resistance, due to the superior pitting resistance. This is distinctly different from the previous case of the Zr53Cu30Ni9Al8 metallic glasses with the reactive Zr2Cu phases inducing serious galvanic corrosion and lower bio-corrosion resistance. Thus, whether the fully amorphous or partially crystallized metallic glass would exhibit better bio-corrosion resistance, the answer would depend on the crystallized phase nature. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Pitting corrosion resistance of nickel-titanium rotary instruments with different surface treatments in seventeen percent ethylenediaminetetraacetic Acid and sodium chloride solutions.

    PubMed

    Bonaccorso, Antonio; Tripi, Teresa Roberta; Rondelli, Gianni; Condorelli, Guglielmo Guido; Cantatore, Giuseppe; Schäfer, Edgar

    2008-02-01

    This study evaluated the pitting corrosion resistance of nickel-titanium (NiTi) rotary instruments with different surface treatments in 17% ethylenediaminetetraacetic acid (EDTA) and NaCl solutions. Electropolished RaCe instruments were allocated to group A, non-electropolished RaCe instruments to group B, and physical vapor deposition (PVD)-coated Alpha files to group C (10 instruments per group). Electrochemical measurements were carried out by using a potentiostat for galvanic current measurements. On the basis of electrochemical tests, no localized corrosion problems are to be expected in EDTA. In NaCl, pitting potential occurred at higher values for the electropolished and PVD instruments, indicating an increased corrosion resistance. There appears to be a risk of corrosion for NiTi instruments without surface treatments in contact with NaCl. NiTi files with PVD and electropolishing surface treatments showed an increase corrosion resistance.

  7. The one-step electroposition of superhydrophobic surface on AZ31 magnesium alloy and its time-dependence corrosion resistance in NaCl solution

    NASA Astrophysics Data System (ADS)

    Zhong, Yuxing; Hu, Jin; Zhang, Yufen; Tang, Shawei

    2018-01-01

    A calcium myristic superhydrophobicity coating with a hierarchical micro-nanostructure was fabricated on AZ31 magnesium alloy by one-step electroposition. The effects of deposition time on the coating structure, such as morphology, thickness, wettability and phase composition of the coating were studied. The corrosion behavior of the coated samples in 3.5% NaCl solution was also investigated and the corrosion mechanism was discussed. It was found that the deposition time has a visible effect on the morphology, thickness and wettability, which distinctly affects the corrosion resistance of coatings. The corrosion resistance of the coating gradually decreases with the increase in the immersion time due to the disappearance of the air layer which exists on the coating surface. The superhydrophobic surfaces present the temporal limitations to the corrosion resistance of AZ31 magnesium alloy.

  8. Direct growth of cerium oxide nanorods on diverse substrates for superhydrophobicity and corrosion resistance

    NASA Astrophysics Data System (ADS)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo; Kim, Dong Rip

    2015-06-01

    Superhydrophobic surfaces with anti-corrosion properties have attracted great interest in many industrial fields, particularly to enhance the thermal performance of offshore applications such as heat exchangers, pipelines, power plants, and platform structures. Nanostructures with hydrophobic materials have been widely utilized to realize superhydrophobicity of surfaces, and cerium oxide has been highlighted due to its good corrosion resistive and intrinsically hydrophobic properties. However, few studies of direct growth of cerium oxide nanostructures on diverse substrates have been reported. Herein we report a facile hydrothermal method to directly grow cerium oxide nanorods on diverse substrates, such as aluminum alloy, stainless steel, titanium, and silicon. Diverse substrates with cerium oxide nanorods exhibited superhydrophobicity with no hydrophobic modifiers on their surfaces, and showed good corrosion resistive properties in corrosive medium. We believe our method could pave the way for realization of scalable and sustainable corrosion resistive superhydrophobic surfaces in many industrial fields.

  9. In-situ monitoring of undercoating corrosion damage by Direct Optical Interrogation (DOI)

    NASA Astrophysics Data System (ADS)

    Lopez-Garrity, Meng

    An approach referred to as "Direct Optical Interrogation" (DOI) has been developed as an extension of the thin film pitting approach developed and used by Frankel and others. Samples were prepared by depositing Al and Al-Cu alloy metallizations about 800 nm thick on glass substrates. These metallizations were then coated with various coatings and coating systems. Samples were introduced to aggressive environments and the progression of corrosion of the metallization under the coating was monitored in situ using low power videography. Because metallizations were thin, corrosion quickly penetrated through the metal layer to the glass substrate and then spread laterally. Measurement of the lateral spread of corrosion enabled non-electrochemical assessment of the corrosion kinetics. In Al-Cu thin films, both aged and as-deposited, corrosion sites are irregularly shaped because there is not enough cathodic current to propagate the entire corrosion site margin at equal rates. In a number of cases, corrosion propagates with a filamentary morphology resembling filiform corrosion. Cu played a strong role in determining under coating corrosion morphology and growth kinetics in experiments with Al-Cu thin films substrates. As-deposited Al-Cu metallizations were more corrosion resistant than aged metallization and both were more corrosion resistant than pure Al. Cu-rich dendrites were formed on the corrosion front. Corrosion rate (current density) was calculated using Faraday's law by collecting corrosion site perimeter and bottom area. Systematic exploration of the effects of a chromate and chromate-free conversion coatings, chromate and chromate-free primer coatings and the presence or absence of a polyurethane topcoat confirmed the extraordinary corrosion protection by chromates. A commercial praseodymium-pigmented primer coating was not particularly effective in retarding undercoating corrosion site growth unless paired with a chromate conversion coating. The presence of a topcoat dramatically reduces undercoating corrosion and masks many deficiencies of a conversion coating or primer. DOI was used to compare undercoating corrosion that developed due to exposure in ASTM B117, ASTM G85-A5 and outdoor environments. Similar corrosion morphologies developed in ASTM B117 and static immersion exposures. A single and stable corrosions site nucleated and propagated with a filamentary morphology. In general, salt spray exposure was more aggressive than static immersion. ASTM G85-A5 exposure produced different corrosion morphologies. Corrosion sites were round rather than filamentary. Massive nucleation of small corrosion sites across the whole surface also occurred. ASTM G85 environment was mild compared with the ASTM B117 and static immersion exposures. In outdoor exposure testing carried out for 5 months, no signs of corrosion was observed. To assess the extent to which oxygen reduction occurring on the coated surface supported corrosion site growth, a universal pH indicator was added to agar gels or PVB coatings applied on top of metallizations. Color changes indicating pH changes associated with local alkalization or acidification due to local cell action were assessed visually. Overall, the evidence is consistent with the idea that both hydrogen reduction and oxygen reduction support local corrosion site growth. In practical embodiments of corrosion protection, every effort should be made to restrict oxygen reduction to slow corrosion growth rates.

  10. Influence of Fluoride Ion Concentrations on the Corrosion Behavior of Ta2N Nanocrystalline Coating for Dental Implant Applications

    NASA Astrophysics Data System (ADS)

    Xu, Jiang; Ma, Jin Jin; Munroe, Paul; Xie, Zong-Han

    The development of new corrosion-resistant coatings is often challenging, but strongly driven by the potential benefits such coatings hold. A nanostructured Ta2N coating was deposited on a Ti-6Al-4V substrate in an Ar-N atmosphere using a double cathode glow discharge plasma method with the aim being to improve its corrosion resistance in oral environments. The microstructure of the coating was investigated by a range of methods including XRD, SEM-EDS and TEM. The as-deposited coating exhibited densely packed fibrous structure and the individual fibers were composed of equiaxed grains with an average grain size ˜13nm, arranged along the longitudinal axis of the individual fibers. The electrochemical behavior of the Ta2N nanocrystalline coating was characterized in artificial saliva containing different NaF concentrations by a range of electrochemical techniques, including potentiodynamic measurement, EIS, capacitance and PZFC measurements. It was shown that the coating possessed superior corrosion resistance compared to uncoated Ti-6Al-4V, because its passive film exhibited higher stability against the fluoride ion attack.

  11. Corrosion Behavior of Aqua-Blasted and Laser-Engraved Type 316L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Krawczyk, B.; Cook, P.; Hobbs, J.; Engelberg, D. L.

    2017-12-01

    The effect of aqua blasting and laser engraving on surface microstructure development, residual stress and corrosion resistance of type 316L stainless steel has been investigated. Aqua blasting resulted in a deformed near-surface microstructure containing compressive residual stresses. Subsequent laser engraving produced a surface layer with tensile residual stresses reaching to a depth of 200 microns. Changes of surface roughness topography were accompanied by the development of a thick oxide/hydroxide film after laser engraving. The atmospheric corrosion behavior of all surfaces with MgCl2-laden droplets was compared to their electrochemical response in 1M NaCl and 0.7 M HCl aqueous solutions. The measured total volume loss after atmospheric corrosion testing was similar for all investigated surface conditions. Laser-engraved surface exhibited the smallest number of corrosion sites, but the largest mean corrosion depth.

  12. KSC lubricant testing program. [lubrication characteristics and corrosion resistance

    NASA Technical Reports Server (NTRS)

    Lockhart, B. J.; Bryan, C. J.

    1973-01-01

    A program was conducted to evaluate the performance of various lubricants in use and considered for use at Kennedy Space Center (KSC). The overall objectives of the program were to: (1) determine the lubrication characteristics and relative corrosion resistance of lubricants in use and proposed for use at KSC; (2) identify materials which may be equivalent to or better than KELF-90 and Krytox 240 AC greases; and (3) identify or develop an improved lubricating oil suitable for use in liquid oxygen (LOX) pumps at KSC. It was concluded that: (1) earth gel thickened greases are very poor corrosion preventive materials in the KSC environment; (2) Halocarbon 25-5S and Braycote 656 were suitable substiutes for KELF-90 and Krytox 240 AC respectively; and (3) none of the oils evaluated possessed the necessary inertness, lubricity, and corrosion prevention characteristics for the KSC LOX pumping systems in their present configuration.

  13. Enhanced corrosion resistance of magnesium alloy by a silane-based solution treatment after an in-situ formation of the Mg(OH)2 layer

    NASA Astrophysics Data System (ADS)

    Gong, Fubao; Shen, Jun; Gao, Runhua; Xie, Xiong; Luo, Xiong

    2016-03-01

    A novel organic-inorganic Mg(OH)2/silane surface layer has been developed for corrosion protection of AZ31 magnesium alloy. The results of electrochemical impedance spectroscopy (EIS), the immersion tests, Fourier-transform infrared spectroscopy (FTIR) and sellotape tests showed that the Mg(OH)2/silane-based composite surface layer possessed excellent corrosion resistance and very good adhesion due to the formation of Si-O-Mg bond between Mg(OH)2 layer and silane layer. Electrochemical impedance spectroscopy tests results indicated that for the long-term corrosion protection of AZ31 the increase of the curing temperature improved the impedance of the composited layer when the curing temperature was lower than 130 °С. However, the impedance of the composited layer deceased when the curing temperature was more than 130 °С due to the carbonization of the silane layer.

  14. Development and evaluation of magnesium oxide-based ceramics for chamber parts in mass-production plasma etching equipment

    NASA Astrophysics Data System (ADS)

    Kasashima, Yuji; Tsutsumi, Kota; Mitomi, Shinzo; Uesugi, Fumihiko

    2017-06-01

    In mass-production plasma etching equipment, the corrosion of ceramic chamber parts reduces the production yield of LSI and overall equipment effectiveness (OEE) owing to contamination, short useful life, and particle generation. Novel ceramics that can improve the production yield and OEE are highly required. We develop magnesium oxide (MgO)-based ceramics and evaluate them under mass-production plasma etching conditions. The results of this study indicate that the developed MgO-based ceramics with high mechanical properties and low electric resistivity have a higher resistance to corrosion in plasma etching using CF4 gas than Si and conventional ceramic materials such as aluminum oxide and yttrium oxide.

  15. 2D Heterostructure coatings of hBN-MoS2 layers for corrosion resistance

    NASA Astrophysics Data System (ADS)

    Vandana, Sajith; Kochat, Vidya; Lee, Jonghoon; Varshney, Vikas; Yazdi, Sadegh; Shen, Jianfeng; Kosolwattana, Suppanat; Vinod, Soumya; Vajtai, Robert; Roy, Ajit K.; Sekhar Tiwary, Chandra; Ajayan, P. M.

    2017-02-01

    Heterostructures of atomically thin 2D materials could have improved physical, mechanical and chemical properties as compared to its individual components. Here we report, the effect of heterostructure coatings of hBN and MoS2 on the corrosion behavior as compared to coatings employing the individual 2D layer compositions. The poor corrosion resistance of MoS2 (widely used as wear resistant coating) can be improved by incorporating hBN sheets. Depending on the atomic stacking of the 2D sheets, we can further engineer the corrosion resistance properties of these coatings. A detailed spectroscopy and microscopy analysis has been used to characterize the different combinations of layered coatings. Detailed DFT based calculation reveals that the effect on the electrical properties due to atomic stacking is one of the major reasons for the improvement seen in corrosion resistance.

  16. Resistance to Corrosion of Zirconia Coatings Deposited by Spray Pyrolysis in Nitrided Steel

    NASA Astrophysics Data System (ADS)

    Cubillos, G. I.; Olaya, J. J.; Bethencourt, M.; Cifredo, G.; Blanco, G.

    2013-10-01

    Coatings of zirconium oxide were deposited onto three types of stainless steel, AISI 316L, 2205, and tool steel AISI D2, using the ultrasonic spray pyrolysis method. The effect of the flux ratio on the process and its influence on the structure and morphology of the coatings were investigated. The coatings obtained, 600 nm thick, were characterized using x-ray diffraction, scanning electron microscopy, confocal microscopy, and atomic force microscopy. The resistance to corrosion of the coatings deposited over steel (not nitrided) and stainless steel nitrided (for 2 h at 823 K) in an ammonia atmosphere was evaluated. The zirconia coating enhances the stainless steel's resistance to corrosion, with the greatest increase in corrosion resistance being observed for tool steel. When the deposition is performed on previously nitrided stainless steel, the morphology of the surface improves and the coating is more homogeneous, which leads to an improved corrosion resistance.

  17. Characterization of corrosion resistant on NiCoCr coating layer exposed to 5%NaCl

    NASA Astrophysics Data System (ADS)

    Sugiarti, E.; Sundawa, R.; Desiati, R. D.; Zaini, K. A.

    2018-03-01

    Highly corrosion resistant of carbon steel coated NiCoCr was applied in corrosive of marine environtment. Carbon steel coated NiCoCr was prepared by a two step technique of NiCo electro-deposition and Cr pack cementation. The samples were exposed to 5 wt.% NaCl for 48 and 168 hours. The microstructure and corrosion product were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The corrosion resistance of carbon steel coated NiCoCr was found to be better than that of carbon steel substrate without coating. The results showed the microstructure of 48 h corroded sample has duplex layer composed of inner α-(Ni,Co), α-Cr and outer Cr2O3, while a quite thin and continues protective oxide of Cr2O3 was observed in outer layer of 168 h corroded sample. The formation of oxide scale rich in Cr2O3 has contributed for the better corrosion resistance of carbon steel coated NiCoCr, whereas the formation of non protective oxide of iron might caused low corrosion resistance of carbon steel substrate.

  18. Microstructure Instability of Candidate Fuel Cladding Alloys: Corrosion and Stress Corrosion Cracking Implications

    NASA Astrophysics Data System (ADS)

    Jiao, Yinan; Zheng, Wenyue; Guzonas, David; Kish, Joseph

    2016-02-01

    This paper addresses some of the overarching aspects of microstructure instability expected from both high temperature and radiation exposure that could affect the corrosion and stress corrosion cracking (SCC) resistance of the candidate austenitic Fe-Cr-Ni alloys being considered for the fuel cladding of the Canadian supercritical water-cooled reactor (SCWR) concept. An overview of the microstructure instability expected by both exposures is presented prior to turning the focus onto the implications of such instability on the corrosion and SCC resistance. Results from testing conducted using pre-treated (thermally-aged) Type 310S stainless steel to shed some light on this important issue are included to help identify the outstanding corrosion resistance assessment needs.

  19. [The effect of bacteria reaction time on corrosion properties of Ni-Cr alloys pretreated with different proteins].

    PubMed

    Qi, Han-quan; Zhang, Song-mei; Qian, Chao; Yuan-Li, Zheng

    2015-12-01

    To evaluate the corrosion properties of absorbed protein on the surface of NiCr alloys, and provide experimental base for corrosion resistance of dental casting alloys. NiCr alloy specimens were divided into 3 groups: one group was exposed to the artificial saliva(control group), and the other 2 groups were exposed to the artificial saliva with 1% bovine serum albumin(BSA), or 0.22% lysozyme(LSZ). Group of BSA and group of LSZ were the experimental group. Specimens in 3 groups were cultured in solution of Streptococcus mutans for 12 h, 24 h, 36 h and 48h, and investigated with electrochemical impedance spectroscopy measurement(EIS) and potentiodynamic polarization measurement(POT) to determine the corrosion resistance of the alloys. The data was analyzed with SPSS 17.0 software package. The results indicated that the corrosion resistance of both BSA group and LSZ group were higher than that of the control group (P<0.05) and LSZ group was superior to BSA group cultured in the solution of Streptococcus mutans for 12 h. When cultured for 24 h, the corrosion resistance of BSA group and LSZ group had no significant difference (P>0.05), but was still higher than that of the control group. After 36 h culture time, the control group and the BSA group had no statistical difference in corrosion resistance （P>0.05), while the LSZ group had the poorest corrosion resistance. When the culture time extended to 48 h, the control group had a better corrosion resistance compared with the BAS group and the LSZ group(P<0.05), but BSA group had displayed lower corrosion properties than LSZ group. The potentiodynamic polarization curve and electrochemical impedance spectroscopy had similar results. The adhesion of BSA and LSZ on the surface of the NiCr alloys in the early time could effectively inhibit the corrosive effect of Streptococcus mutans. The LSZ had better effect than BSA. With the continuing role of bacteria and the consumption of the absorb protein, the corrosion resistance of NiCr alloys toward Streptococcus mutans becomes lower than the alloys without absorb protein, which demonstrated that the adhesion of protein would change the surface structure of NiCr alloys and BSA had a greater effect.

  20. Effect of temperature on anodic behavior of 13Cr martensitic steel in CO2 environment

    NASA Astrophysics Data System (ADS)

    Zhao, G. X.; Zheng, M.; Lv, X. H.; Dong, X. H.; Li, H. L.

    2005-04-01

    The corrosion behavior of 13Cr martensitic stainless steel in a CO2 environment in a stimulated oilfield was studied with potentiodynamic polarization and the impedance spectra technique. The results showed that the microstructure of the surface scale clearly changed with temperature. This decreased the sensitivity of pitting corrosion and increased the tendency toward general (or uniform) corrosion. The capacitance, the charge transfer resistance, and the polarization resistance of the corrosion product scale decrease with increasing temperature from 90 to 120 °C, and thus the corrosion is a thermal activation controlled process. Charge transfer through the scale is difficult and the corrosion is controlled by a diffusion process at a temperature of 150 °C. Resistance charge transfer through the corrosion product layer is higher than that in the passive film.

  1. Assessment of corrosion resistance of Nd-Fe-B magnets by silanization for orthodontic applications

    NASA Astrophysics Data System (ADS)

    Fabiano, F.; Celegato, F.; Giordano, A.; Borsellino, C.; Bonaccorsi, L.; Calabrese, L.; Tiberto, P.; Cordasco, G.; Matarese, G.; Fabiano, V.; Azzerboni, B.

    2014-02-01

    Nd-Fe-B permanent magnets are characterised by excellent magnetic properties. However, being extremely vulnerable to the attack of both climate and corrosive environments, their applications are limited. This paper describes how, at different thicknesses of N-propyl-trimetoxy-silane, the coating affects the magnetic force of nickel plated magnets. We also investigate if the corrosion resistance of silanized Nd-Fe-B magnets increases in mildly corrosive environments by immersing them in a synthetic saliva solution. It was found that the silanization treatment does not affect the strength of the magnetic force and provide an enhancement of the corrosion resistance of the substrate.

  2. Triple-wavelength, narrowband Mg/SiC multilayers with corrosion barriers and high peak reflectance in the 25-80 nm wavelength region

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fernández-Perea, Mónica; Soufli, Regina; Robinson, Jeff C.

    2012-01-01

    We have developed new, corrosion-resistant Mg/SiC multilayer coatings which can be used to efficiently and simultaneously reflect extreme ultraviolet (EUV) radiation in single or multiple narrow bands centered at wavelengths in the spectral region from 25 to 80 nm. Corrosion mitigation is achieved through the use of partially amorphous Al-Mg thin layers. Three different multilayer design concepts were developed and deposited by magnetron sputtering and the reflectance was measured at near-normal incidence in a broad spectral range. Unprotected Mg/SiC multilayers were also deposited and measured for comparison. They were shown to efficiently reflect radiation at a wavelength of 76.9 nmmore » with a peak reflectance of 40.6% at near-normal incidence, the highest experimental reflectance reported at this wavelength for a narrowband coating. The demonstration of multilayer coatings with corrosion resistance and multiplewavelength EUV performance is of great interest in the development of mirrors for space-borne solar physics telescopes and other applications requiring long-lasting coatings with narrowband response in multiple emission lines across the EUV range.« less

  3. Creation of superhydrophobic stainless steel surfaces by acid treatments and hydrophobic film deposition.

    PubMed

    Li, Lester; Breedveld, Victor; Hess, Dennis W

    2012-09-26

    In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6°, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9°, respectively, while maintaining corrosion resistance.

  4. The Use of AC-DC-AC Methods in Assessing Corrosion Resistance Performance of Coating Systems for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    McCune, Robert C.; Upadhyay, Vinod; Wang, Yar-Ming; Battocchi, Dante

    The potential utility of AC-DC-AC electrochemical methods in comparative measures of corrosion-resisting coating system performance for magnesium alloys under consideration for the USAMP "Magnesium Front End Research and Development" project was previously shown in this forum [1]. Additional studies of this approach using statistically-designed experiments have been conducted with focus on alloy types, pretreatment, topcoat material and topcoat thickness as the variables. Additionally, sample coupons made for these designed experiments were also subjected to a typical automotive cyclic corrosion test cycle (SAE J2334) as well as ASTM B117 for comparison of relative performance. Results of these studies are presented along with advantages and limitations of the proposed methodology.

  5. 75 FR 45094 - Antidumping or Countervailing Duty Order, Finding, or Suspended Investigation; Opportunity To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-02

    ... review Antidumping Duty Proceedings Germany: Corrosion-Resistant Carbon Steel Flat Products, A- 8/1/09-7...-805.. South Korea: Corrosion-Resistant Carbon Steel Flat 8/1/09-7/31/10 Products, A-580-816 Light... South Korea: Corrosion-Resistant Carbon Steel Flat Products, C- 1/1/09-12/31/09 580-818 Stainless Steel...

  6. Investigation of passive films formed on the surface of alloy 690 in borate buffer solution

    NASA Astrophysics Data System (ADS)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Wenli, Guo

    2015-10-01

    The passive film formed on the surface of the alloy 690 in borate buffer solution was studied by potentiodynamic curves and electrochemical impedance spectroscopy. With the increasing of the passivation potential, the corrosion resistance of the alloy 690 reduced. Moreover, the corrosion resistance of the passive film was the lowest in the vicinity of 0.6 VSCE. These results were supported by XPS and Mott-Schottky analyses. The corrosion resistance of the alloy 690 increased with the increasing of passivated potential in borate buffer solution with chloride ion. The chloride ion decreased corrosion resistance of the alloy 690 according to point defect model.

  7. Surface Modification Concepts for Enhancement of the High-Temperature Corrosion Resistance of Gas Turbine Superalloys,

    DTIC Science & Technology

    1980-12-01

    now developed to the point where they could be considered as true engineering materials. ** Nickel-based alloys are used for turbine blading and...Introduction Implicit in the design of modern gas turbine engines is the premise that their aerofoil components, made of nickel- and cobalt-based...the deposit. Hot corrosion is a principal process of degradation of aerofoil surface integrity in gas turbine engines . 2.2 Mechanisms of Hot Corrosion

  8. Mitigating Intergranular Stress Corrosion Cracking in Age-Hardenable Al-Zn-Mg-Cu Alloys

    NASA Astrophysics Data System (ADS)

    Ajay Krishnan, M.; Raja, V. S.; Shukla, Shweta; Vaidya, S. M.

    2018-04-01

    This article reports an attempt to develop high-strength aluminum alloys of 7xxx series resistant to intergranular stress corrosion cracking (SCC). A novel aging technique reported in this work exhibited improved strength levels (as high as 100 MPa to that of conventional overaged temper for AA 7050) with significant resistance to SCC measured even at a low strain rate (10-7 s-1) in 3.5 wt pct NaCl. The novel aging heat treatment produced a microstructure that is finer and dense enough in the matrix to impart strength, whereas it is enriched with Cu on the grain boundaries to impart SCC resistance. A detailed explanation for the enhanced strength and SCC resistance is discussed.

  9. Mitigating Intergranular Stress Corrosion Cracking in Age-Hardenable Al-Zn-Mg-Cu Alloys

    NASA Astrophysics Data System (ADS)

    Ajay Krishnan, M.; Raja, V. S.; Shukla, Shweta; Vaidya, S. M.

    2018-06-01

    This article reports an attempt to develop high-strength aluminum alloys of 7xxx series resistant to intergranular stress corrosion cracking (SCC). A novel aging technique reported in this work exhibited improved strength levels (as high as 100 MPa to that of conventional overaged temper for AA 7050) with significant resistance to SCC measured even at a low strain rate (10-7 s-1) in 3.5 wt pct NaCl. The novel aging heat treatment produced a microstructure that is finer and dense enough in the matrix to impart strength, whereas it is enriched with Cu on the grain boundaries to impart SCC resistance. A detailed explanation for the enhanced strength and SCC resistance is discussed.

  10. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Some methods of increasing the density of metal in order to increase him corrosion resistance

    NASA Astrophysics Data System (ADS)

    Chumanov, I. V.; Anikeev, A. N.; Sergeev, D. V.; Maltseva, A. N.

    2017-11-01

    Methods to increase the density of metal in order to increase its corrosion resistance in an aggressive environment are examined in the article. Two steel grades, differing in the content of alloying elements, increasing the resistance to corrosion are selected for the manufacture of experimental metallic materials. Two technologies are chosen as methods for increasing the density, and as a result, corrosion resistance, of the experimental materials obtained: the first is electroslag remelting with rotation of the consumable electrode, the second is centrifugal casting with modification. The microstructure of the metal becomes more homogeneous, the degree of metal refining from non-metallic inclusions increases, the rate of crystallization during metal smelting by the ESR method increases with rotation of the consumable electrode. When ingots are produced by the method of centrifugal casting, they are modified with dispersed WC and TiC particles, which increases the crystallization rate, increases the metal density, corrosion and mechanical properties. The evaluation of their corrosion resistance with the help of the autoclaved test complex “Cortest” is made after obtaining ingots by various technologies.

  12. Electrochemical anodizing treatment to enhance localized corrosion resistance of pure titanium.

    PubMed

    Prando, Davide; Brenna, Andrea; Bolzoni, Fabio M; Diamanti, Maria V; Pedeferri, Mariapia; Ormellese, Marco

    2017-01-26

    Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.

  13. 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.

  14. Improved biological performance of magnesium by micro-arc oxidation

    PubMed Central

    Ma, W.H.; Liu, Y.J.; Wang, W.; Zhang, Y.Z.

    2014-01-01

    Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO), which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications. PMID:25517917

  15. Vacuum Sputtered and Ion-Plated Coatings for Wear and Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1982-01-01

    The plasma or ion-assisted coating techniques such as sputtering and ion plating are discussed in view of wear and corrosion protection. The basic processes and the unique features of the technique are discussed in regard to the synthesis and development of high reliability wear and corrosion resistant films. The ions of the plasma which transfer energy, momentum, and charge to the substrate and the growing films can be beneficially used. As a result, coating adherence and cohesion is improved. Favorable morphological growth such as high density and porosity-free films can be developed, and residual stresses can be reduced.

  16. A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

    PubMed Central

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-01-01

    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. PMID:24084117

  17. 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.

  18. Effect of Hydroxyapatite on the Mechanical Properties and Corrosion Behavior of Mg-Zn-Y Alloy

    PubMed Central

    Chiu, Chun; Lu, Chih-Te; Chen, Shih-Hsun; Ou, Keng-Liang

    2017-01-01

    Mg-Zn-Y alloys with a long period stacking ordered (LPSO) phase are potential candidates for biodegradable implants; however, an unfavorable degradation rate has limited their applications. Hydroxyapatite (HA) has been shown to enhance the corrosion resistance of Mg alloys. In this study, Mg97Zn1Y2-0.5 wt% HA composite was synthesized and solution treated at 500 °C for 10 h. The corrosion behavior of the composite was studied by electrochemical and immersion tests, while the mechanical properties were investigated by a tensile test. Addition of HA particles improves the corrosion resistance of Mg97Zn1Y2 alloy without sacrificing tensile strength. The improved corrosion resistance is due to the formation of a compact Ca-P surface layer and a decrease of the volume fraction of the LPSO phase, both resulting from the addition of HA. After solution-treatment, the corrosion resistance of the composite decreases. This is due to the formation of a more extended LPSO phase, which weakens its role as a corrosion barrier in protecting the Mg matrix. PMID:28773216

  19. In vitro corrosion resistance of Lotus-type porous Ni-free stainless steels.

    PubMed

    Alvarez, Kelly; Hyun, Soong-Keun; Fujimoto, Shinji; Nakajima, Hideo

    2008-11-01

    The corrosion behavior of three kinds of austenitic high nitrogen Lotus-type porous Ni-free stainless steels was examined in acellular simulated body fluid solutions and compared with type AISI 316L stainless steel. The corrosion resistance was evaluated by electrochemical techniques, the analysis of released metal ions was performed by inductively coupled plasma mass spectrometry (ICP-MS) and the cytotoxicity was investigated in a culture of murine osteoblasts cells. Total immunity to localized corrosion in simulated body fluid (SBF) solutions was exhibited by Lotus-type porous Ni-free stainless steels, while Lotus-type porous AISI 316L showed very low pitting corrosion resistance evidenced by pitting corrosion at a very low breakdown potential. Additionally, Lotus-type porous Ni-free stainless steels showed a quite low metal ion release in SBF solutions. Furthermore, cell culture studies showed that the fabricated materials were non-cytotoxic to mouse osteoblasts cell line. On the basis of these results, it can be concluded that the investigated alloys are biocompatible and corrosion resistant and a promising material for biomedical applications.

  20. Laser Surface Alloying of Aluminum for Improving Acid Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Jiru, Woldetinsay Gutu; Sankar, Mamilla Ravi; Dixit, Uday Shanker

    2018-04-01

    In the present study, laser surface alloying of aluminum with magnesium, manganese, titanium and zinc, respectively, was carried out to improve acid corrosion resistance. Laser surface alloying was conducted using 1600 and 1800 W power source using CO2 laser. Acid corrosion resistance was tested by dipping the samples in a solution of 2.5% H2SO4 for 200 h. The weight loss due to acid corrosion was reduced by 55% for AlTi, 41% for AlMg alloy, 36% for AlZn and 22% for AlMn alloy. Laser surface alloyed samples offered greater corrosion resistance than the aluminum substrate. It was observed that localized pitting corrosion was the major factor to damage the surface when exposed for a long time. The hardness after laser surface alloying was increased by a factor of 8.7, 3.4, 2.7 and 2 by alloying with Mn, Mg, Ti and Zn, respectively. After corrosion test, hardness was reduced by 51% for AlTi sample, 40% for AlMg sample, 41.4% for AlMn sample and 33% for AlZn sample.

  1. Corrosion Properties of Cryorolled AA2219 Friction Stir Welded Joints Using Different Tool Pin Profiles

    NASA Astrophysics Data System (ADS)

    Kamal Babu, K.; Panneerselvam, K.; Sathiya, P.; Noorul Haq, A.; Sundarrajan, S.; Mastanaiah, P.; Srinivasa Murthy, C. V.

    The purpose of this paper is to present the corrosion behavior of the Cryorolled (CR) material and its Friction Stir Welded joints. Due to the thermal cycles of Friction Stir Welding (FSW) process, the corrosion behavior of the material gets affected. Here, the cryorolling process was carried out on AA2219 alloy and CR material was joined by FSW process using four different pin tool profiles such as cylindrical, threaded cylindrical, square and hexagonal pin. The FSW joints were analyzed by corrosion resistance with the help of potentiodynamic polarization test with 3.5% NaCl solution. From the analysis, it is found that CR AA2219 material exhibits good corrosion resistance compared to the base AA2219 material, and also a hexagonal pin profile FSW joint exhibits high corrosion resistance. Among the weld joints created by four different tools, the lowest corrosion resistance was found in the cylindrical pin tool FSW welds. Further, the corroded samples were investigated through metallurgical investigations like OM, Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDX) and X-Ray Diffraction (XRD). It was found that the amount of dissolution of Al2Cu precipitate was present in the weld nugget. The amount of dissolution of Al2Cu precipitate is higher in the weld nugget produced by hexagonal pin tool. This is due to the enhancement of the corrosion resistance.

  2. 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.

  3. Corrosion of titanium: Part 1: aggressive environments and main forms of degradation.

    PubMed

    Prando, Davide; Brenna, Andrea; Diamanti, Maria Vittoria; Beretta, Silvia; Bolzoni, Fabio; Ormellese, Marco; Pedeferri, MariaPia

    2017-11-11

    Titanium has outstanding corrosion resistance due to the external natural oxide protective layer formed when it is exposed to an aerated environment. Despite this, titanium may suffer different forms of corrosion in severe environments: uniform corrosion, pitting and crevice corrosion, hydrogen embrittlement, stress-corrosion cracking, fretting corrosion and erosion. In this first review, forms of corrosion affecting titanium are analyzed based on a wide literature review. For each form of corrosion, the mechanism and most severe environment are reported according to the current understanding.In the second part, this review will address the possible surface treatments that can increase corrosion resistance on commercially pure titanium: Electrochemical anodizing, thermal oxidation, chemical oxidation and bulk treatments such as alloying will be considered, highlighting the advantages of each technique.

  4. Optimization of cladding parameters for resisting corrosion on low carbon steels using simulated annealing algorithm

    NASA Astrophysics Data System (ADS)

    Balan, A. V.; Shivasankaran, N.; Magibalan, S.

    2018-04-01

    Low carbon steels used in chemical industries are frequently affected by corrosion. Cladding is a surfacing process used for depositing a thick layer of filler metal in a highly corrosive materials to achieve corrosion resistance. Flux cored arc welding (FCAW) is preferred in cladding process due to its augmented efficiency and higher deposition rate. In this cladding process, the effect of corrosion can be minimized by controlling the output responses such as minimizing dilution, penetration and maximizing bead width, reinforcement and ferrite number. This paper deals with the multi-objective optimization of flux cored arc welding responses by controlling the process parameters such as wire feed rate, welding speed, Nozzle to plate distance, welding gun angle for super duplex stainless steel material using simulated annealing technique. Regression equation has been developed and validated using ANOVA technique. The multi-objective optimization of weld bead parameters was carried out using simulated annealing to obtain optimum bead geometry for reducing corrosion. The potentiodynamic polarization test reveals the balanced formation of fine particles of ferrite and autenite content with desensitized nature of the microstructure in the optimized clad bead.

  5. Formulation and Assessment of a Wash-Primer Containing Lanthanum "Tannate" for Steel Temporary Protection

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Oriana; Selmi, Gonzalo J.; Deyá, Cecilia; Di Sarli, Alejandro; Romagnoli, Roberto

    2018-02-01

    Tannins are polyphenols synthesized by plants and useful for the coating industry as corrosion inhibitors. In addition, lanthanum salts have a great inhibitory effect on steel corrosion. The aim of this study was to obtain lanthanum "tannate" with adequate solubility to be incorporated as the corrosion inhibitor in a wash-primer. The "tannate" was obtained from commercial "Quebracho" tannin and 0.1 M La(NO3)3. The soluble tannin was determined by the Folin-Denis reagent, while the concentration of Lanthanum was obtained by a gravimetric procedure. The protective action of "tannate" on SAE 1010 steel was evaluated by linear polarization curves and corrosion potential measurements. Lanthanum "tannate" was incorporated in a wash-primer formulation and tested by corrosion potential and ionic resistance measurements. The corrosion rate was also determined by the polarization resistance technique. Besides, the primer was incorporated in an alkyd paint system and its anticorrosion performance assessed in the salt spray cabinet and by electrochemical impedance spectroscopy. Results showed that lanthanum "tannate" primer inhibits the development of deleterious iron oxyhydroxides on the steel substrate and incorporated into a paint system had a similar behavior to the primer formulated with zinc tetroxychromate.

  6. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study

    PubMed Central

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-01-01

    An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography. PMID:28626241

  7. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study.

    PubMed

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-03-01

    An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography.

  8. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    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.

  9. 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.

  10. Durable Corrosion and Ultraviolet-Resistant Silver Mirror

    DOEpatents

    Jorgensen, G. J.; Gee, R.

    2006-01-24

    A corrosion and ultra violet-resistant silver mirror for use in solar reflectors; the silver layer having a film-forming protective polymer bonded thereto, and a protective shield overlay comprising a transparent multipolymer film that incorporates a UV absorber. The corrosion and ultraviolet resistant silver mirror retains spectral hemispherical reflectance and high optical clarity throughout the UV and visible spectrum when used in solar reflectors.

  11. 76 FR 45773 - Antidumping or Countervailing Duty Order, Finding, or Suspended Investigation; Opportunity To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

    ... Proceedings Germany: Corrosion-Resistant Carbon Steel Flat Products, A- 8/1/10-7/31/11 428-815 Certain Small... (Under 4\\1/2\\ Inches), A-485-805.. South Korea: Corrosion-Resistant Carbon Steel Flat Products, A- 8/1/10... Korea: Corrosion-Resistant Carbon Steel Flat Products, C- 1/1/10-12/31/10 580-818 Stainless Steel Sheet...

  12. Experimental investigation of microbiologically influenced corrosion of selected steels in sugarcane juice environment.

    PubMed

    Wesley, Sunil Bala; Maurya, Devendra Prasad; Goyal, Hari Sharan; Negi, Sangeeta

    2013-12-01

    In the current study, ferritic stainless grades AISI 439 and AISI 444 were investigated as possible construction materials for machinery and equipment in the cane-sugar industry. Their performance in corrosive cane-sugar juice environment was compared with the presently used low carbon steel AISI 1010 and austenitic stainless steel AISI 304. The Tafel plot electrochemical technique was used to evaluate general corrosion performance. Microbiologically influenced corrosion (MIC) behaviour in sugarcane juice environment was studied. Four microbial colonies were isolated from the biofilms on the metal coupon surfaces on the basis of their different morphology. These were characterized as Brevibacillus parabrevis, Bacillus azotoformans, Paenibacillus lautus and Micrococcus sp. The results of SEM micrographs showed that AISI 439 and AISI 304 grades had suffered maximum localized corrosion. MIC investigations revealed that AISI 444 steel had the best corrosion resistance among the tested materials. However from the Tafel plots it was evident that AISI 1010 had the least corrosion resistance and AISI 439 the best corrosion resistance.

  13. Sulfide stress corrosion study of a super martensitic stainless steel in H2S sour environments: Metallic sulfides formation and hydrogen embrittlement

    NASA Astrophysics Data System (ADS)

    Monnot, Martin; Nogueira, Ricardo P.; Roche, Virginie; Berthomé, Grégory; Chauveau, Eric; Estevez, Rafael; Mantel, Marc

    2017-02-01

    Thanks to their high corrosion resistance, super martensitic stainless steels are commonly used in the oil and gas industry, particularly in sour environments. Some grades are however susceptible to undergo hydrogen and mechanically-assisted corrosion processes in the presence of H2S, depending on the pH. The martensitic stainless steel EN 1.4418 grade exhibits a clear protective passive behavior with no sulfide stress corrosion cracking when exposed to sour environments of pH ≥ 4, but undergoes a steep decrease in its corrosion resistance at lower pH conditions. The present paper investigated this abrupt loss of corrosion resistance with electrochemical measurements as well as different physicochemical characterization techniques. Results indicated that below pH 4.0 the metal surface is covered by a thick (ca 40 μm) porous and defect-full sulfide-rich corrosion products layer shown to be straightforwardly related to the onset of hydrogen and sulfide mechanically-assisted corrosion phenomena.

  14. Towards lightweight nanocomposite coatings for corrosion inhibition: Graphene, carbon nanotubes, and nanostructured magnesium as case studies

    NASA Astrophysics Data System (ADS)

    Dennis, Robert Vincent, III

    The field of nanocomposites is a burgeoning area of research due to the interest in the remarkable properties which can be achieved through their use in a variety of applications, including corrosion resistant coatings. Lightweighting is of increasing importance in the world today due to the ever growing push towards energy efficiency and the green movement and in recent years there has been a vast amount of research performed in the area of developing lightweight nanocomposites for corrosion inhibition. Many new composite materials have been developed through the use of newly developed nanomaterials (including carbonaceous and metallic constituents) and their specialized incorporation in the coating matrix materials. We start with a general review on the development of hybrid nanostructured composites for corrosion protection of base metals from a sustainability perspective in Chapter 1. This review demonstrates the ever swelling requirements for a paradigm shift in the way that we protect metals against corrosion due to the costs and environmental concerns that exist with currently used technology. In Chapter 2, we delve into the much required understanding of graphene oxide and reduced graphene oxide through near-edge X-ray absorption fine structure (NEXAFS) spectroscopy measurements to elucidate information about the electronic structure upon incorporation of nitrogen within the structure. For successful integration of the carbonaceous nanomaterials into a composite coating, a full swath of knowledge is necessary. Within this work we have shown that upon chemical defunctionalization of graphene oxide to reduced graphene oxide by means of hydrazine treatment, nitrogen is incorporated into the structure in the form of a pyrazole ring. In Chapter 3, we demonstrate that by way of in situ polymerization, graphene and multiwalled carbon nanotubes can be incorporated within a polymer (polyetherimide, PEI) matrix. Two systems have been developed including graphene and multiwalled carbon nanotubes that act synergistically at a concentration of 2 wt.% each along with graphene at 20 wt.%. The in situ polymerization technique allows for well dispersed carbon nanomaterials within the polymer matrix, which is always a necessary requirement for success as a multifunctional composite coating. After testing in harsh corrosive brine environments these coatings outperformed the polymer by itself and even Zn galvanized steel, lowering the estimated corrosion rate by several orders of magnitude. Chapter 4 displays the possible uses of functionalized carbon nanomaterials in the design of a nanocomposite for corrosion resistance. In this work we establish a method of crosslinking and curing of the polymer matrix using the carbon nanofiller materials as a curing agent through the knowledge partially developed from work outlined in Chapter 2. Here we have used the native functional groups (hydroxyls and carboxylic acids) on graphene oxide and oxidized multiwalled carbon nanotubes to initiate the curing reaction with a well-known commercially available and commonly used epoxy resin. This technology allows for the chemical integration of the nanofiller within the polymer matrix, ensuring excellent dispersion, and also removing the need for often toxic curing agents. The nanocomposites created here have also been tested for their corrosion resistant properties. Concluding with Chapter 5, we exploit some of our previous work on the development of nanostructured magnesium for use in corrosion resistant coatings based on Mg-rich primer technology. It was shown that Mg nanoplatelets allow for a much increased surface area for interaction with the polymer matrix, leading to excellent property enhancement at a significantly reduced pigment volume concentration and coating thickness. These enhancements lead to less material being used, lighter/thinner coatings, and improved performance. These nano Mg-rich primer formulations were shown to protect the underlying steel substrates from corrosion upon breakdown, in the form of a scratch to the metal surface, of the coating; preferentially oxidizing before the iron in steel. The coatings also were found to reduce the corrosion rate by up to 4 orders of magnitude.

  15. A study on corrosion resistance of dissimilar welds between Monel 400 and 316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Mani, Cherish; Karthikeyan, R.; Vincent, S.

    2018-04-01

    An attempt has been made to study the corrosion resistance of bi-metal weld joints of Monel 400 tube to stainless steel 316 tube by GTAW process. The present research paper contributes to the ongoing research work on the use of Monel400 and 316L austenitic stainless steel in industrial environments. Potentiodynamic method is used to investigate the corrosion behavior of Monel 400 and 316L austenitic stainless steel welded joints. The analysis has been performed on the base metal, heat affected zone and weld zone after post weld heat treatment. Optical microscopy was also performed to correlate the results. The heat affected zone of Monel 400 alloy seems to have the lowest corrosion resistance whereas 316L stainless steel base metal has the highest corrosion resistance.

  16. Improvement of diamond-like carbon electrochemical corrosion resistance by addition of nanocrystalline diamond.

    PubMed

    Marciano, F R; Almeida, E C; Bonetti, L F; Corat, E J; Trava-Airoldi, V J

    2010-02-15

    Nanocrystalline diamond (NCD) particles were incorporated into diamond-like carbon (DLC) films in order to investigate NCD-DLC electrochemical corrosion resistance. The films were grown over 304 stainless steel using plasma-enhanced chemical vapor deposition. NCD particles were incorporated into DLC during the deposition process. The investigation of NCD-DLC electrochemical corrosion behavior was performed using potentiodynamic polarization against NaCl. NCD-DLC films presented more negative corrosion potential and lower anodic and cathodic current densities. The electrochemical analysis indicated that NCD-DLC films present superior impedance and polarization resistance compared to the pure DLC, which indicate that they are promising corrosion protective coatings in aggressive solutions. Copyright 2009 Elsevier Inc. All rights reserved.

  17. Corrosion Resistance of Laser Clads of Inconel 625 and Metco 41C

    NASA Astrophysics Data System (ADS)

    Němeček, Stanislav; Fidler, Lukáš; Fišerová, Pavla

    The present paper explores the impact of laser cladding parameters on the corrosion behaviour of the resulting surface. Powders of Inconel 625 and austenitic Metco 41C steel were deposited on steel substrate. It was confirmed that the level of dilution has profound impact on the corrosion resistance and that dilution has to be minimized. However, the chemical composition of the cladding is altered even in the course of the cladding process, a fact which is related to the increase in the substrate temperature. The cladding process was optimized to achieve maximum corrosion resistance. The results were verified and validated using microscopic observation, chemical analysis and corrosion testing.

  18. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    PubMed

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

  19. Novel Corrosion Sensor for Vision 21 Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 indicationmore » 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.« less

  20. 77 FR 13093 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ...-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or iron-based alloys, whether or not... Special Taxation Act (RSTA) Article 26 II. Programs That Provided No Benefits During the POR A. Research and Development Grants Under the Industrial Development Act (IDA) B. Research and Development Grants...

  1. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    NASA Astrophysics Data System (ADS)

    Niroumandrad, S.; Rostami, M.; Ramezanzadeh, B.

    2015-12-01

    The objective of this study was to enhance the corrosion resistance of lamellar aluminum pigment through surface treatment by cerium oxides/hydroxides. The surface composition of the pigments was studied by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the pigment was evaluated by conventional hydrogen evolution measurements in acidic solution and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. Results showed that the Ce-rich coating composed of Ce2O3 and CeO2 was precipitated on the pigment surface after immersion in the cerium solution. The corrosion resistance of pigment was significantly enhanced after modification with cerium layer.

  2. Development of AC impedance methods for evaluating corroding metal surfaces and coatings

    NASA Technical Reports Server (NTRS)

    Knockemus, Ward

    1986-01-01

    In an effort to investigate metal surface corrosion and the breakdown of metal protective coatings the AC Impedance Method was applied to zinc chromate primer coated 2219-T87 aluminum. The model 368-1 AC Impedance Measurement System recently acquired by the MSFC Corrosion Research Branch was used to monitor changing properties of coated aluminum disks immersed in 3.5% NaCl buffered at ph 5.5 over three to four weeks. The DC polarization resistance runs were performed on the same samples. The corrosion system can be represented by an electronic analog called an equivalent circuit that consists of transistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for resistances and capacities that can be assigned in the equivalent circuit following a least squares analysis of the data describe changes that occur on the corroding metal surface and in the protective coating. A suitable equivalent circuit was determined that predicts the correct Bode phase and magnitude for the experimental sample. The DC corrosion current density data are related to equivalent circuit element parameters.

  3. Effect of fibre laser marking on surface properties and corrosion resistance of a Fe-Ni-Cr alloy

    NASA Astrophysics Data System (ADS)

    Astarita, Antonello; Mandolfino, Chiara; Lertora, Enrico; Gambaro, Carla; Squillace, Antonino; Scherillo, Fabio

    2017-10-01

    Fiber laser techniques are increasing their use in many applications, including modification of material surface properties. In particular they are often used for materials' marking as a non-contact processing. In spite of this, the impact of the laser beam on the surface causes metallurgical and morphological changes. The developments during the laser-material interaction can also affect other surface properties, especially corrosion properties which are crucial in the case of Iron-Nickel alloys. Effect of laser marking on a Fe-Cr-Ni alloy using a Tm-fibre laser (IPG Photonics TRL1904; maximum power: 50W, wavelength: 1904 nm), is described in this paper. In order to evaluate the effect of the laser on corrosion properties a specific ageing test in salt spray has been performed. Moreover, superficial morphology analyses have been performed on samples before and after corrosion tests. Possibilities and limitations of laser marking on these alloys have been discussed, in particular from the point of view of the marked surface corrosion resistance preservation.

  4. Microstructure and hydrothermal corrosion behavior of NITE-SiC with various sintering additives in LWR coolant environments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parish, Chad M.; Terrani, Kurt A.; Kim, Young -Jin

    Nano-infiltration and transient eutectic phase (NITE) sintering was developed for fabrication of nuclear grade SiC composites. We produced monolithic SiC ceramics using NITE sintering, as candidates for accident-tolerant fuels in light-water reactors (LWRs). In this work, we exposed three different NITE chemistries (yttria-alumina [YA], ceria-zirconia-alumina [CZA], and yttria-zirconia-alumina [YZA]) to autoclave conditions simulating LWR coolant loops. The YZA was most corrosion resistant, followed by CZA, with YA being worst. High-resolution elemental analysis using scanning transmission electron microscopy (STEM) X-ray mapping combined with multivariate statistical analysis (MVSA) datamining helped explain the differences in corrosion. YA-NITE lost all Al from the corrodedmore » region and the ytttria reformed into blocky precipitates. The CZA material lost all Al from the corroded area, and the YZA – which suffered the least corrosion –retained some Al in the corroded region. Lastly, the results indicate that the YZA-NITE SiC is most resistant to hydrothermal corrosion in the LWR environment.« less

  5. The chemical durability of tektites - A laboratory study and correlation with long-term corrosion behavior

    NASA Technical Reports Server (NTRS)

    Barkatt, A.; Boulos, M. S.; Barkatt, A.; Sousanpour, W.; Boroomand, M. A.; Macedo, P. B.; Okeefe, J. A.

    1984-01-01

    Leach tests carried out on tektite specimens (indochinites and australites) under high-dilution conditions show a common behavior characterized by low leach rates (0.00018 g/sq m per d, or 7.2 x 10 to the -12th m/d at 23 C) and an activation energy of (79,600 + or - 700 J/mol). The extent of selective leaching is very small, of the order of 10 to the -8th m. Extrapolation of test results over the lifetime of the tektites gives an excellent agreement with field observations on the extent of corrosion, and this is an important step in establishing the validity of laboratory tests as a basis for the development of models and predictions concerning long-term durabilities at least in the limiting case of high dilution or rapid flow. The results are also shown to be in agreement with various previous observations on the corrosion resistance of tektites. The chemical durability of tektites is observed to be consistent with their composition, highlighting requirements of high corrosion resistance in glasses; these requirements include a silica content in excess of 67 mol percent, an extremely low water content, and an alkali content which is low both absolutely and relative to the di- and poly-valent metal oxide levels. It is shown that artificial glasses which fulfil these criteria are no less corrosion-resistant than the corresponding natural glasses. These conclusions have bearing on the development, as well as on the evaluation, of glasses intended for very long service, such as radioactive waste vitrification media.

  6. Conjoint corrosion and wear in titanium alloys.

    PubMed

    Khan, M A; Williams, R L; Williams, D F

    1999-04-01

    When considering titanium alloys for orthopaedic applications it is important to examine the conjoint action of corrosion and wear. In this study we investigate the corrosion and wear behaviour of Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr in phosphate buffered saline (PBS), bovine albumin solutions in PBS and 10% foetal calf serum solutions in PBS. The tests were performed under four different conditions to evaluate the influence of wear on the corrosion and corrosion on the wear behaviour as follows: corrosion without wear, wear-accelerated corrosion, wear in a non-corrosive environment and wear in a corrosive environment. The corrosion behaviour was investigated using cyclic polarisation studies to measure the ability of the surface to repassivate following breakdown of the passive layer. The properties of the repassivated layer were evaluated by measuring changes in the surface hardness of the alloys. The amount of wear that had occurred was assessed from weight changes and measurement of the depth of the wear scar. It was found that in the presence of wear without corrosion the wear behaviour of Ti-13Nb-13Zr was greater than that of Ti-6Al-7Nb or Ti-6Al-4V and that in the presence of proteins the wear of all three alloys is reduced. In the presence of corrosion without wear Ti-13Nb-13Zr was more corrosion resistant than Ti-6Al-7Nb which was more corrosion resistant than Ti-6Al-4V without proteins whereas in the presence of protein the corrosion resistance of Ti-13Nb-13Zr and Ti-6Al-7Nb was reduced and that of Ti-6Al-4V increased. In the presence of corrosion and wear the corrosion resistance of Ti-13Nb-13Zr is higher than that of Ti-6Al-7Nb or Ti-6Al-4V in PBS but in the presence of proteins the corrosion resistance of Ti-13Nb-13Zr and Ti-6Al-7Nb are very similar but higher than that of Ti-6Al-4V. The wear of Ti-13Nb-13Zr is lower than that of Ti-6Al-7Nb and Ti-6Al-4V with or without the presence of proteins in a corrosive environment. Therefore the overall degradation when both corrosion and wear processes are occurring is lowest for Ti-13Nb-13Zr and highest for Ti-6Al-4V and the presence of proteins reduces the degradation of all three alloys.

  7. Effect of Annealing Temperature on the Mechanical and Corrosion Behavior of a Newly Developed Novel Lean Duplex Stainless Steel.

    PubMed

    Guo, Yanjun; Hu, Jincheng; Li, Jin; Jiang, Laizhu; Liu, Tianwei; Wu, Yanping

    2014-09-12

    The effect of annealing temperature (1000-1150 °C) on the microstructure evolution, mechanical properties, and pitting corrosion behavior of a newly developed novel lean duplex stainless steel with 20.53Cr-3.45Mn-2.08Ni-0.17N-0.31Mo was studied by means of optical metallographic microscopy (OMM), scanning electron microscopy (SEM), magnetic force microscopy (MFM), scanning Kelvin probe force microscopy (SKPFM), energy dispersive X-ray spectroscopy (EDS), uniaxial tensile tests (UTT), and potentiostatic critical pitting temperature (CPT). The results showed that tensile and yield strength, as well as the pitting corrosion resistance, could be degraded with annealing temperature increasing from 1000 up to 1150 °C. Meanwhile, the elongation at break reached the maximum of 52.7% after annealing at 1050 °C due to the effect of martensite transformation induced plasticity (TRIP). The localized pitting attack preferentially occurred at ferrite phase, indicating that the ferrite phase had inferior pitting corrosion resistance as compared to the austenite phase. With increasing annealing temperature, the pitting resistance equivalent number (PREN) of ferrite phase dropped, while that of the austenite phase rose. Additionally, it was found that ferrite possessed a lower Volta potential than austenite phase. Moreover, the Volta potential difference between ferrite and austenite increased with the annealing temperature, which was well consistent with the difference of PREN.

  8. Effect of Annealing Temperature on the Mechanical and Corrosion Behavior of a Newly Developed Novel Lean Duplex Stainless Steel

    PubMed Central

    Guo, Yanjun; Hu, Jincheng; Li, Jin; Jiang, Laizhu; Liu, Tianwei; Wu, Yanping

    2014-01-01

    The effect of annealing temperature (1000–1150 °C) on the microstructure evolution, mechanical properties, and pitting corrosion behavior of a newly developed novel lean duplex stainless steel with 20.53Cr-3.45Mn-2.08Ni-0.17N-0.31Mo was studied by means of optical metallographic microscopy (OMM), scanning electron microscopy (SEM), magnetic force microscopy (MFM), scanning Kelvin probe force microscopy (SKPFM), energy dispersive X-ray spectroscopy (EDS), uniaxial tensile tests (UTT), and potentiostatic critical pitting temperature (CPT). The results showed that tensile and yield strength, as well as the pitting corrosion resistance, could be degraded with annealing temperature increasing from 1000 up to 1150 °C. Meanwhile, the elongation at break reached the maximum of 52.7% after annealing at 1050 °C due to the effect of martensite transformation induced plasticity (TRIP). The localized pitting attack preferentially occurred at ferrite phase, indicating that the ferrite phase had inferior pitting corrosion resistance as compared to the austenite phase. With increasing annealing temperature, the pitting resistance equivalent number (PREN) of ferrite phase dropped, while that of the austenite phase rose. Additionally, it was found that ferrite possessed a lower Volta potential than austenite phase. Moreover, the Volta potential difference between ferrite and austenite increased with the annealing temperature, which was well consistent with the difference of PREN. PMID:28788201

  9. 46 CFR 160.044-3 - General requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... used shall be of good quality and suitable for the purpose intended, and shall be corrosion-resistant or protected against corrosion by acceptable means, except that parts subject to wear shall not depend upon coatings for corrosion resistance. (b) Bilge pumps covered by this subpart shall be capable...

  10. 46 CFR 160.044-3 - General requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... used shall be of good quality and suitable for the purpose intended, and shall be corrosion-resistant or protected against corrosion by acceptable means, except that parts subject to wear shall not depend upon coatings for corrosion resistance. (b) Bilge pumps covered by this subpart shall be capable...

  11. Development of improved high temperature coatings for IN-792 + HF

    NASA Technical Reports Server (NTRS)

    Profant, D. D.; Naik, S. K.

    1981-01-01

    The development for t-55 l712 engine of high temperature for integral turbine nozzles with improved thermal fatigue resistance without sacrificing oxidation/corrosion protection is discussed. The program evaluated to coating systems which comprised one baseline plasma spray coating (12% Al-NiCoCrALY), three aluminide coatings including the baseline aluminide (701), two CoNiCrAly (6% Al) + aluminide systems and four NiCoCrY + aluminide coating were evaluated. The two-step coating processes were investigated since it offered the advantage of tailoring the composition as well as properly coating surfaces of an integral or segmented nozzle. Cyclic burner rig thermal fatigue and oxidation/corrosion tests were used to evaluate the candidate coating systems. The plasma sprayed 12% Al-NiCoCrAlY was rated the best coating in thermal fatigue resistance and outperformed all coatings by a factor between 1.4 to 2.5 in cycles to crack initiation. However, this coatings is not applicable to integral or segmented nozzles due to the line of sight limitation of the plasma spray process. The 6% Al-CoNiCrAlY + Mod. 701 aluminide (32 w/o Al) was rated the best coating in oxidation/corrosion resistance and was rated the second best in thermal fatigue resistance.

  12. Performance of ferritic stainless steels for automobile muffler corrosion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tarutani, Y.; Hashizume, T.

    1995-11-01

    Corrosion behavior of ferritic stainless steels was studied in artificial exhaust gas condensates containing corrosive ions such as Cl{sup {minus}} and SO{sub 3}{sup 2{minus}}. Continuous immersion tests in flasks and Dip and Dry tests by using the alternate corrosion tester with a heating system clarified the effects of chromium and molybdenum additions on the corrosion resistance of a ferritic stainless steel in the artificial exhaust gas condensates. Effects of surface oxidation on the corrosion behavior were investigated in a temperature range of 573K to 673K. Oxidation of 673K reduced the corrosion resistance of the ferritic stainless steels in the artificialmore » environment of the automobile muffler. Particulate matter deposited on the muffler inner shell from the automobile exhaust gas was also examined. Deposited particulate matter increased the corrosion rate of the ferritic stainless steel. Finally, the authors also investigated the corrosion of the automobile mufflers made of Type 436L ferritic stainless steel with 18% chromium-1.2% molybdenum after 24 months, in Japan. The sets of results clarified that Type 436L ferritic stainless steel as the material for the automobile muffler exhibited acceptable corrosion resistance.« less

  13. Physical Metallurgy, Weldability, and in-Service Performance of Nickel-Chromium Filler Metals Used in Nuclear Power Systems

    NASA Astrophysics Data System (ADS)

    Young, George A.; Etien, Robert A.; Hackett, Micah J.; Tucker, Julie D.; Capobianco, Thomas E.

    Wrought Alloy 690 is well established for corrosion resistant nuclear applications but development continues to improve the weldability of a filler metal that retains the corrosion resistance and phase stability of the base metal. High alloy Ni-Cr filler metals are prone to several types of welding defects and new alloys are emerging for commercial use. This paper uses experimental and computational methods to illustrate key differences among welding consumables. Results show that solidification segregation is critical to understanding the weldability and environmentally-assisted cracking resistance of these alloys. Primary water stress corrosion cracking tests show a marked decrease in crack growth rates near 21 wt. % Cr at the grain boundary. While filler metals with 21-29 wt.% grain boundary Cr show similar PWSCC resistance, the higher alloyed grades are more prone to solidification cracking. Modeling and aging studies indicate that in some filler metals minor phase formation (e.g., Laves and σ) and long range order (LRO) must be assessed to ensure adequate weldability and inservice performance.

  14. Investigation of Corrosion Behavior of Ti/TiN Multilayers on Al7075 Deposited by High-Vacuum Magnetron Sputtering in 3.5% NaCl Solution

    NASA Astrophysics Data System (ADS)

    Molavi, Esfandiar; Shanaghi, Ali; Chu, Paul K.

    2018-05-01

    Although Al 7075 has many favorable mechanical properties such as the large strength-to-weight ratio, the relatively poor corrosion resistance has restricted industrial applications. In this work, Ti/TiN as hard multilayered and nanostructured coatings are deposited on the relatively soft Al 7075 structure by high-vacuum radio-frequency magnetron sputtering and the phase, structure, and morphology are investigated in details. The corrosion behavior is evaluated by electrochemical impedance spectroscopy in 3.5% NaCl at a pH of 7.5 for 1, 6, 12, 24, 36, 48, 60, and 72 h. At time points of 1, 6, 12, and 24 h, primary oxide layers and double layers are formed, but the corrosive medium penetrates the primary titanium nitride columnar structure. At longer time points of 24, 36, 48, 60, and 72 h, formation of stronger oxide and double layers leads to better corrosion resistance which is 14.8 times better than that observed from the uncoated substrate after immersion for 36 h. According to R ct, the corrosion resistances of the short and long immersion groups are 808.5-1984 and 808.5-1248 kΩ cm2, respectively, thereby confirming the effectiveness of the Ti/TiN coating against corrosion in comparison with the corrosion resistance of 84.3 kΩ cm2 observed from the uncoated Al 7075. The smallest corrosion resistance of 808.5 kΩ cm2 observed at the time point of 24 h is 9.6 times that of the uncoated substrate.

  15. Increased corrosion resistance of the AZ80 magnesium alloy by rapid solidification.

    PubMed

    Aghion, E; Jan, L; Meshi, L; Goldman, J

    2015-11-01

    Magnesium (Mg) and Mg-alloys are being considered as implantable biometals. Despite their excellent biocompatibility and good mechanical properties, their rapid corrosion is a major impediment precluding their widespread acceptance as implantable biomaterials. Here, we investigate the potential for rapid solidification to increase the corrosion resistance of Mg alloys. To this end, the effect of rapid solidification on the environmental and stress corrosion behavior of the AZ80 Mg alloy vs. its conventionally cast counterpart was evaluated in simulated physiological electrolytes. The microstructural characteristics were examined by optical microscopy, SEM, TEM, and X-ray diffraction analysis. The corrosion behavior was evaluated by immersion, salt spraying, and potentiodynamic polarization. Stress corrosion resistance was assessed by Slow Strain Rate Testing. The results indicate that the corrosion resistance of rapidly solidified ribbons is significantly improved relative to the conventional cast alloy due to the increased Al content dissolved in the α-Mg matrix and the correspondingly reduced presence of the β-phase (Mg17 Al12 ). Unfortunately, extrusion consolidated solidified ribbons exhibited a substantial reduction in the environmental performance and stress corrosion resistance. This was mainly attributed to the detrimental effect of the extrusion process, which enriched the iron impurities and increased the internal stresses by imposing a higher dislocation density. In terms of immersion tests, the average corrosion rate of the rapidly solidified ribbons was <0.4 mm/year compared with ∼2 mm/year for the conventionally cast alloy and 26 mm/year for the rapidly solidified extruded ribbons. © 2014 Wiley Periodicals, Inc.

  16. On the properties of two binary NiTi shape memory alloys. Effects of surface finish on the corrosion behaviour and in vitro biocompatibility.

    PubMed

    Es-Souni, Mohammed; Es-Souni, Martha; Fischer-Brandies, Helge

    2002-07-01

    The present paper compares the transformation behaviour and mechanical properties of two orthodontic wires of close chemical compositions. The effects of surface topography and surface finish residues on the potentiodynamic corrosion behaviour and biocompatibility are also reported. The cytotoxicity tests were performed on both alloys in fibroblast cell cultures from human gingiva using the MTT test. It is shown that the surface finish and the amounts of surface finish residues affect dramatically the corrosion resistance. Bad surface finish results in lower corrosion resistance. The in vitro biocompatibility, though not affected to the extent of corrosion resistance, is also reduced as the surface roughness and the amounts of residues increase. This is thought to be due to surface effects on corrosion and metallic ions release.

  17. Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

    NASA Technical Reports Server (NTRS)

    Pearman, Benjamin Pieter; Calle, Luz M.

    2015-01-01

    This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

  18. Effects of Laser Re-melting on the Corrosion Properties of HVOF Coatings

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Toor, I. H.; Patel, F.; Baig, M. A.

    2013-05-01

    HVOF coating of Inconel 625 powder on carbon steel is carried out. Laser melting of the resulting coating is realized to improve coating structural integrity. Morphological and microstructural changes are examined in the coating prior and after laser treatment process using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction (XRD). The residual stress developed is measured on the surface vicinity of the laser-treated coating using the XRD technique. The corrosion resistance of the laser-treated and untreated coating surfaces is measured, incorporating the potentiodynamic tests in 0.5 M NaCl aqueous solution. It is found that laser treatment reduces the pores and produces cellular structures with different sizes and orientations in the coating. Laser-controlled melting improves the corrosion resistance of the coating surface.

  19. Role of microstructure in caustic stress corrosion cracking of Alloy 690

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mertz, D.A.; Duda, P.T.; Pica, P.N.

    1995-12-31

    Alloy 690 has been selected for nuclear heat transport system tubing application in recent commercial reactor plants due to its resistance to multiple types of corrosion attack. Typical corn final heat treatments for this material are a mill-anneal (MA, approximately 1,070 C) to completely dissolve the carbides and develop the final grain structure plus a thermal treatment (TT, approximately 700 C) to precipitate carbides at the grain boundaries. Tubing with grain boundary carbides and no or few intragranular carbides has been found resistant to intergranular stress corrosion cracking (IGSCC) in caustic environments. In this work, first, Alloy 690 plate wasmore » subjected to a variety of MA and MA-TT heat treatments to create microstructures of carbide-decorated grain boundaries and undecorated boundaries. Caustic IGSCC test results were consistent with tubing data. Second, experiments were conducted to understand the mechanism by which caustic-corrosion resistance is imparted to Alloy 690 by grain boundary carbides. Tubing with a fully-developed MA-TT carbide microstructure was strained and heat-treated to create a mixed microstructure of new grain boundaries with no carbide precipitate decoration, intermixed with intragranular carbide strings from prior grain boundaries. Caustic SCC performance of this material was identical to that of material with the MA-TT carbide-decorated grain boundaries. This work suggests that the fundamental cause of good IGSCC resistance of MA-TT Alloy 690 in caustic does not derive solely from grain boundary carbides. It is suggested that matrix strength, as measured by yield stress, could be a controlling factor.« less

  20. Corrosion resistance and mechanical properties of titanium nitride plating on orthodontic wires.

    PubMed

    Sugisawa, Haruki; Kitaura, Hideki; Ueda, Kyosuke; Kimura, Keisuke; Ishida, Masahiko; Ochi, Yumiko; Kishikawa, Akiko; Ogawa, Saika; Takano-Yamamoto, Teruko

    2018-03-30

    Titanium nitride (TiN) coating by ion plating has properties such as high hardness, wear resistance, corrosion resistance, and surface lubricity, therefore TiN coating is often used in various dental appliances and materials. In this study, we evaluated the corrosion behaviors and mechanical properties of TiN coated stainless steel (SS) and nickel titanium (Ni-Ti) orthodontic wires prepared by ion plating. TiN coating by ion plating improves the corrosion resistance of orthodontic wires. The corrosion pitting of the TiN coated wire surface become small. The tensile strength and stiffness of SS wire were increased after TiN coating. In contrast, its elastic force, which is a property for Ni-Ti wire, was decreased. In addition, TiN coating provided small friction forces. The low level of friction may increase tooth movement efficiently. Therefore, TiN coated SS wire could be useful for orthodontics treatment.

  1. 46 CFR 160.022-3 - Materials, workmanship, construction, and performance requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... be protected with a watertight cover having a finish which is corrosion-resistant to salt water and... when presented with supporting data. Igniter systems shall be corrosion-resistant metal. The... rusting or corrosion and will not back off and loosen under shipboard vibration. (d) Performance. Signals...

  2. 46 CFR 160.022-3 - Materials, workmanship, construction, and performance requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... be protected with a watertight cover having a finish which is corrosion-resistant to salt water and... when presented with supporting data. Igniter systems shall be corrosion-resistant metal. The... rusting or corrosion and will not back off and loosen under shipboard vibration. (d) Performance. Signals...

  3. 46 CFR 160.022-3 - Materials, workmanship, construction, and performance requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... be protected with a watertight cover having a finish which is corrosion-resistant to salt water and... when presented with supporting data. Igniter systems shall be corrosion-resistant metal. The... rusting or corrosion and will not back off and loosen under shipboard vibration. (d) Performance. Signals...

  4. 46 CFR 160.022-3 - Materials, workmanship, construction, and performance requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... be protected with a watertight cover having a finish which is corrosion-resistant to salt water and... when presented with supporting data. Igniter systems shall be corrosion-resistant metal. The... rusting or corrosion and will not back off and loosen under shipboard vibration. (d) Performance. Signals...

  5. Effects of annealing heat treatment on the corrosion resistance of Zn/Mg/Zn multilayer coatings

    NASA Astrophysics Data System (ADS)

    Bae, KiTae; La, JoungHyun; Lee, InGyu; Lee, SangYul; Nam, KyungHoon

    2017-05-01

    Zn coatings alloyed with magnesium offer superior corrosion resistance compared to pure Zn or other Zn-based alloy coatings. In this study, Zn/Mg/Zn multilayer coatings with various Mg layer thicknesses were synthesized using an unbalanced magnetron sputtering process and were annealed to form Zn-Mg intermetallic phases. The effects of the annealing heat treatment on the corrosion resistance of the Zn/Mg/Zn multilayer coatings were evaluated using electrochemical measurements. The extensive diffusion of magnesium species into the upper and lower zinc layer from the magnesium layer in the middle of the coating was observed after the heat treatment. This phenomenon caused (a) the porous microstructure to transition into a dense structure and (b) the formation of a MgZn2 intermetallic phase. The results of the electrochemical measurements demonstrated that the heat treated Zn/Mg/Zn multilayer coatings possessed higher levels of corrosion resistance than the non-heat treated coatings. A Zn/Mg/Zn multilayer coating with MgZn2 and (Zn) phases showed the best corrosion resistance among the heat treated coatings, which could be attributed to the reduced galvanic corrosion effects due to a small potential gradient between the MgZn2 and zinc.

  6. Corrosion Finishing/Coating Systems for DoD Metallic Substrates Based on Non-Chromate Inhibitors and UV Curable, Zero VOC Materials

    DTIC Science & Technology

    2010-08-01

    Corrosion resistant coatings containing non-chromate inhibitors and no volatile organic compounds were developed and evaluated for DoD applications...Transmission Electron Microscopy TRI – Toxic Release Inventory UV – Ultraviolet UVAs – Ultraviolet Absorbers VOCs – Volatile Organic Compounds XPS – X...containing non-chromate inhibitors and no volatile organic compounds were developed and evaluated for DoD applications. The technical effort

  7. Studies of new perfluoroether elastomeric sealants. [for aircraft fuel tanks

    NASA Technical Reports Server (NTRS)

    Basiulis, D. I.; Salisbury, D. P.

    1981-01-01

    Channel and filleting sealants were developed successfully from cyano and diamidoxime terminated perfluoro alkylene ether prepolymers. The prepolymers were polymerized, formulated and tested. The polymers and/or formulations therefrom were evaluated as to their physical, mechanical and chemical properties (i.e., specific gravity, hardness, nonvolatile content, corrosion resistance, stress corrosion, pressure rupture resistance, low temperature flexibility, gap sealing efficiency, tensile strength and elongation, dynamic mechanical behavior, compression set, fuel resistance, thermal properties and processability). Other applications of the formulated polymrs and incorporation of the basic prepolymers into other polymeric systems were investigated. A cyano terminated perfluoro alkylene oxide triazine was formulated and partially evaluated. The channel sealant in its present formulation has excellent pressure rupture resistance and surpasses present MIL specifications before and after fuel and heat aging.

  8. In-vitro long term and electrochemical corrosion resistance of cold deformed nitrogen containing austenitic stainless steels in simulated body fluid.

    PubMed

    Talha, Mohd; Behera, C K; Sinha, O P

    2014-07-01

    This work was focused on the evaluation of the corrosion behavior of deformed (10% and 20% cold work) and annealed (at 1050 °C for 15 min followed by water quenching) Ni-free high nitrogen austenitic stainless steels (HNSs) in simulated body fluid at 37°C using weight loss method (long term), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. Scanning electron microscopy (SEM) was used to understand the surface morphology of the alloys after polarization test. It has been observed that cold working had a significant influence on the corrosion resistant properties of these alloys. The weight loss and corrosion rates were observed to decrease with increasing degree of cold working and nitrogen content in the alloy. The corrosion resistance of the material is directly related to the resistance of the passive oxide film formed on its surface which was enhanced with cold working and nitrogen content. It was also observed that corrosion current densities were decreased and corrosion potentials were shifted to more positive values. By seeing pit morphology under SEM, shallower and smaller pits were associated with HNSs and cold worked samples, indicating that corrosion resistance increases with increasing nitrogen content and degree of cold deformation. X-ray diffraction profiles of annealed as well as deformed alloys were revealed and there is no evidence for formation of martensite or any other secondary phases. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. A Simple and Reliable Setup for Monitoring Corrosion Rate of Steel Rebars in Concrete

    PubMed Central

    Jibran, Mohammed Abdul Azeem; Azad, Abul Kalam

    2014-01-01

    The accuracy in the measurement of the rate of corrosion of steel in concrete depends on many factors. The high resistivity of concrete makes the polarization data erroneous due to the Ohmic drop. The other source of error is the use of an arbitrarily assumed value of the Stern-Geary constant for calculating corrosion current density. This paper presents the outcomes of a research work conducted to develop a reliable and low-cost experimental setup and a simple calculation procedure that can be utilised to calculate the corrosion current density considering the Ohmic drop compensation and the actual value of the Stern-Geary constants calculated using the polarization data. The measurements conducted on specimens corroded to different levels indicate the usefulness of the developed setup to determine the corrosion current density with and without Ohmic drop compensation. PMID:24526907

  10. Effect of Fly-Ash on Corrosion Resistance Characteristics of Rebar Embedded in Recycled Aggregate Concrete

    NASA Astrophysics Data System (ADS)

    Revathi, Purushothaman; Nikesh, P.

    2018-04-01

    In the frame of an extended research programme dealing with the utilization of recycled aggregate in concrete, the corrosion resistance characteristics of rebars embedded in recycled aggregate concrete is studied. Totally five series of concrete mixtures were prepared with fly-ash as replacement for cement in the levels of 10-30% by weight of cement. Corrosion studies by 90 days ponding test, linear polarization test and impressed voltage tests were carried out, in order to investigate whether corrosion behaviour of the rebars has improved due to the replacement of cement with fly-ash. Results showed that the replacement of cement with fly-ash in the range of 20-30% improves the corrosion resistance characteristics of recycled aggregate concrete.

  11. A study of the effect of clinical washing decontamination process on corrosion resistance of Martensitic Stainless Steel 420.

    PubMed

    Xu, Yunwei; Huang, Zhihong; Corner, George

    2016-09-28

    Corrosion of surgical instruments provides a seat for contamination and prevents proper sterilisation, placing both patients and medical staff at risk of infection. Corrosion can also compromise the structural integrity of instruments and lead to mechanical failure in use. It is essential to understand the various factors affecting corrosion resistance of surgical instruments and how it can be minimised.This paper investigates the effect on corrosion resistance from the clinical washing decontamination (WD) process, specifically by studying the changes in surface roughness and Cr/Fe ratio. Results indicate that the WD process provides a positive effect on smooth polished samples, while a lesser positive effect was observed on rough reflection reduced samples.

  12. 40 CFR 60.759 - Specifications for active collection systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... generation rates and flow characteristics, cover properties, gas system expandibility, leachate and..., air intrusion control, corrosion resistance, fill settlement, and resistance to the refuse..., fiberglass, stainless steel, or other nonporous corrosion resistant material of suitable dimensions to...

  13. Corrosion Behavior and Strength of Dissimilar Bonding Material between Ti and Mg Alloys Fabricated by Spark Plasma Sintering

    PubMed Central

    Pripanapong, Patchara; Kariya, Shota; Luangvaranunt, Tachai; Umeda, Junko; Tsutsumi, Seiichiro; Takahashi, Makoto; Kondoh, Katsuyoshi

    2016-01-01

    Ti and solution treated Mg alloys such as AZ31B (ST), AZ61 (ST), AZ80 (ST) and AZ91 (ST) were successfully bonded at 475 °C by spark plasma sintering, which is a promising new method in welding field. The formation of Ti3Al intermetallic compound was found to be an important factor in controlling the bonding strength and galvanic corrosion resistance of dissimilar materials. The maximum bonding strength and bonding efficiency at 193 MPa and 96% were obtained from Ti/AZ91 (ST), in which a thick and uniform nano-level Ti3Al layer was observed. This sample also shows the highest galvanic corrosion resistance with a measured galvanic width and depth of 281 and 19 µm, respectively. The corrosion resistance of the matrix on Mg alloy side was controlled by its Al content. AZ91 (ST) exhibited the highest corrosion resistance considered from its corrode surface after corrosion test in Kroll’s etchant. The effect of Al content in Mg alloy on bonding strength and corrosion behavior of Ti/Mg alloy (ST) dissimilar materials is discussed in this work. PMID:28773788

  14. Improve sensitization and corrosion resistance of an Al-Mg alloy by optimization of grain boundaries

    NASA Astrophysics Data System (ADS)

    Yan, Jianfeng; Heckman, Nathan M.; Velasco, Leonardo; Hodge, Andrea M.

    2016-05-01

    The sensitization and subsequent intergranular corrosion of Al-5.3 wt.% Mg alloy has been shown to be an important factor in stress corrosion cracking of Al-Mg alloys. Understanding sensitization requires the review of grain boundary character on the precipitation process which can assist in developing and designing alloys with improved corrosion resistance. This study shows that the degree of precipitation in Al-Mg alloy is dependent on grain boundary misorientation angle, adjacent grain boundary planes and grain boundary types. The results show that the misorientation angle is the most important factor influencing precipitation in grain boundaries of the Al-Mg alloy. Low angle grain boundaries (≤15°) have better immunity to precipitation and grain boundary acid attack. High angle grain boundaries (>15°) are vulnerable to grain boundary acid attack. Grain boundaries with adjacent plane orientations near to {100} have potential for immunity to precipitation and grain boundary acid attack. This work shows that low Σ (Σ ≤ 29) coincident site lattice (CSL) grain boundaries have thinner β precipitates. Modified nitric acid mass loss test and polarization test demonstrated that the global corrosion resistance of sputtered Al-Mg alloy is enhanced. This may be attributed to the increased fractions of low Σ (Σ ≤ 29) CSL grain boundaries after sputtering.

  15. Organosilane self-assembled layers (SAMs) and hybrid silicate magnesium-rich primers for the corrosion protection of aluminum alloy 2024 T3

    NASA Astrophysics Data System (ADS)

    Wang, Duhua

    Although current chromate coatings function very well in corrosion protection for aircraft alloys, such as aluminum alloy 2024 T3, the U.S. Environmental Protection Agency is planning to totally ban the use of chromates as coating materials in the next decade or so because of their extremely toxic effect. For this purpose, both self-assembled layers and silicate magnesium-rich primers were tested to provide the corrosion protection for aluminum alloy. The long-term goal of this research is to develop a coating system to replace the current chromate coating for aircraft corrosion protection. Aluminum alloy 2024 T3 substrates were modified with self-assembled monolayer or multilayer thin films from different alkylsilane compounds. Mono-functional silanes, such as octadecyltrichlorosilane (C18SiCl3), can form a mixed hydrophobic monolayer or multilayer thin film on the aluminum oxide surface to provide a barrier to water and other electrolytes, so the corrosion resistance of the SAMs modified surface was increased significantly. On the other hand, the bi-functional silane self-assembly could attach the aluminum surface through the silicon headgroup while using its functional tailgroup to chemically bond the polymer coating, thus improving the adhesion between the aluminum substrate and coating substantially, and seems to contribute more to corrosion protection of aluminum substrate. Organosilanes were also combined with tetraethyl orthosilicate (TEOS) in propel ratios to form a sol-gel binder to make silicate magnesium-rich primers. Analogue to the inorganic zinc-rich coatings, the silicate magnesium-rich primers also showed excellent adhesion and solvent resistance. The sacrificial magnesium pigments and the chemically inert silicate binder both contribute to the anti-corrosion properties. Future studies will be focused on the formula optimization for better toughness, chemical resistance and anticorrosion performance.

  16. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    NASA Astrophysics Data System (ADS)

    García-Rentería, M. A.; López-Morelos, V. H.; González-Sánchez, J.; García-Hernández, R.; Dzib-Pérez, L.; Curiel-López, F. F.

    2017-02-01

    The effect of electromagnetic interaction of low intensity (EMILI) applied during fusion welding of AISI 2205 duplex stainless steel on the resistance to localised corrosion in natural seawater was investigated. The heat affected zone (HAZ) of samples welded under EMILI showed a higher temperature for pitting initiation and lower dissolution under anodic polarisation in chloride containing solutions than samples welded without EMILI. The EMILI assisted welding process developed in the present work enhanced the resistance to localised corrosion due to a modification on the microstructural evolution in the HAZ and the fusion zone during the thermal cycle involved in fusion welding. The application of EMILI reduced the size of the HAZ, limited coarsening of the ferrite grains and promoted regeneration of austenite in this zone, inducing a homogeneous passive condition of the surface. EMILI can be applied during fusion welding of structural or functional components of diverse size manufactured with duplex stainless steel designed to withstand aggressive environments such as natural seawater or marine atmospheres.

  17. Layer-by-Layer Assembly of a Self-Healing Anticorrosion Coating on Magnesium Alloys.

    PubMed

    Fan, Fan; Zhou, Chunyu; Wang, Xu; Szpunar, Jerzy

    2015-12-16

    Fabrication of self-healing anticorrosion coatings has attracted attention as it has the ability to extend the service life and prevent the substrate from corrosive attack. However, a coating system with a rapid self-healing ability and an improved corrosion resistance is rarely reported. In this work, we developed a self-healing anticorrosion coating on a magnesium alloy (AZ31). The coating comprises a cerium-based conversion layer, a graphene oxide layer, and a branched poly(ethylene imine) (PEI)/poly(acrylic acid) (PAA) multilayer. We incorporated the graphene oxide as corrosion inhibitors and used the PEI/PAA multilayers to provide the self-healing ability to the coating systems. X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the composition of the multilayers, and scanning electron microscopy (SEM) was used to analyze the surface morphology. The electrochemical impedance spectroscopy (EIS) results illustrate the improved corrosion resistance of the coating. The proposed coating also has a rapid self-healing ability in the presence of water.

  18. Effect of immersion time in a modified green death solution on the rust layer of Cu-containing low-alloy steel

    NASA Astrophysics Data System (ADS)

    Kim, Seon-Hong; Kwon, Min-Seok; Kim, Jung-Gu

    2017-01-01

    The corrosion resistance of low-alloy steel containing 0.35 wt% copper, as a function of immersion time in a modified green death solution, was investigated using electrochemical methods and surface analysis. After 30 min of immersion, the steel surface was covered with a Cu-enriched film. Improvement of the film properties and increases in the corrosion resistance were realized for the immersion time up to 6 h due to the development of the Cu-enriched layer. However, the Cu particle was formed in the Cu-enriched layer for the immersion time beyond 6 h. Since the formation of the Cu particle generated a Cu-depletion region, micro-galvanic corrosion between the Cu particle and the Cu-depletion region lead to the localized film breakdown on the surface film. The localized film breakdown, which decreased the corrosion properties of the Cu-containing steel, was accelerated by the continuous formation of Cu particles in the rust layer.

  19. Improved fracture toughness corrosion-resistant bearing material

    NASA Technical Reports Server (NTRS)

    Bamberger, E. N.; Nahm, A. H.

    1986-01-01

    A development program was performed to establish whether a corrosion-resistant bearing material, such as a 14Cr steel, could be modified to allow carburization, thereby providing the excellent fracture toughness characteristics feasible with this process. The alloy selected for investigation was AMS 5749. Several modifications were made including the addition of a small amount of nickel for austenite stabilization. While some promising results were achieved, the primary objective of an acceptable combination of case hardness and microstructure was not attained. Because the high chromium content presents a serious problem in achieving a viable carburizing cycle, a number of experimental steels having lower chromium contents (8 to 12%) were produced in laboratory quantities and evaluated. The results were basically the same as those initially obtained with the modified AMS 5749. Corrosion tests were performed on AMS 5749, AISI M50, and 52100 bearing steels as well as some of the lower chromium steels. These tests showed that a reduced chromium level (10 to 12%) provided essentially the same corrosion protection as the 14Cr steels.

  20. Mechanical and Microstructural Characterization of a New Corrosion Resistant Stainless Steel

    NASA Astrophysics Data System (ADS)

    Voiculescu, I.; Geantă, V.; Stefănoiu, R.; Cotruţ, C.; Ciocoiu, R.; Ionescu, M.

    2018-06-01

    The paper investigates the manner in which the chemical composition and delivery status of a new type of stainless steel, highly alloyed with Ni and Cr, affect mechanical properties, microstructure and corrosion resistance. The results obtained during the mechanical test (tensile, compression, Charpy test and micro-hardness) have revealed promising values. During the corrosion test, the preferential attack of the reagent (Aqua regia) located on the grain boundaries, inclusions or polyhedral precipitates have been observed. On the corroded surfaces, some localized pitting effects on grain boundaries have been revealed. The analyses of the parameter values recorded during the corrosion test revealed that the corrosion current density had a low value, comparable to that of other specific types of stainless steels. The actual Icorr (1.089 µA/cm2) value measured for the experimental alloy proves good resistance to corrosion in 3% NaCl saline solution. The estimated rate of corrosion presented acceptable values (0.011 mm/year).

  1. Dependence of Crystallographic Orientation on Pitting Corrosion Behavior of Ni-Fe-Cr Alloy 028

    NASA Astrophysics Data System (ADS)

    Zhang, LiNa; Szpunar, Jerzy A.; Dong, JianXin; Ojo, Olanrewaju A.; Wang, Xu

    2018-06-01

    The influence of crystallographic orientation on the pitting corrosion behavior of Ni-Fe-Cr alloy 028 was studied using a combination of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), potentiodynamic polarization technique, and atomic force microscopy (AFM). The results show that there is anisotropy of pitting corrosion that strongly depends on crystallographic orientation of the surface plane. The distribution of pit density in a standard stereographic triangle indicates that the crystallographic planes close to {100} are more prone to pitting corrosion compared to planes {110} and {111}. The surface energy calculation of (001) and (111) shows that the plane with a high atomic packing density has a low surface energy with concomitant strong resistance to pitting corrosion. A correlation function between crystallographic orientation and pitting corrosion susceptibility suggests a method that not only predicts the pitting resistance of known textured materials, but also could help to improve corrosion resistance by controlling material texture.

  2. Geothermal materials development

    NASA Astrophysics Data System (ADS)

    Kukacka, L. E.

    1991-12-01

    Advances in the development of new materials, the commercial availabilities of which are essential for the attainment of Hydrothermal Category Level 1 and 2 Objectives, continue to be made in the Geothermal Materials Development Project. Many successes have already been accrued and the results used commercially. In FY-91, utility company sponsored 'full cost' recovery programs based upon materials technology developed in this project were initiated on topics such as condensing heat exchangers, high temperature composites for utility vaults used in district heating systems, and corrosion resistant coatings for use in oil-fired electric generating processes. In FY-91, the DOE/GD-sponsored R&D project was focused on reducing well drilling, fluid transport and energy conversion costs. Specific activities being performed included lightweight CO2-resistant well cements, chemical systems for lost circulation control, thermally conductive and scale resistant protective linear systems, corrosion mitigation in process components at The Geysers, and elastomer-metal bonding systems needed for use in high temperature well drilling and safety related applications.

  3. Development of rapidly quenched nickel-based non-boron filler metals for brazing corrosion resistant steels

    NASA Astrophysics Data System (ADS)

    Ivannikov, A.; Kalin, B.; Suchkov, A.; Penyaz, M.; Yurlova, M.

    2016-04-01

    Corrosion-resistant steels are stably applied in modern rocket and nuclear technology. Creating of permanent joints of these steels is a difficult task that can be solved by means of welding or brazing. Recently, the use rapidly quenched boron-containing filler metals is perspective. However, the use of such alloys leads to the formation of brittle borides in brazing zone, which degrades the corrosion resistance and mechanical properties of the compounds. Therefore, the development of non-boron alloys for brazing stainless steels is important task. The study of binary systems Ni-Be and Ni-Si revealed the perspective of replacing boron in Ni-based filler metals by beryllium, so there was the objective of studying of phase equilibrium in the system Ni-Be-Si. The alloys of the Ni-Si-Be with different contents of Si and Be are considered in this paper. The presence of two low-melting components is revealed during of their studying by methods of metallography analysis and DTA. Microhardness is measured and X-ray diffraction analysis is conducted for a number of alloys of Ni-Si-Be. The compositions are developed on the basis of these data. Rapidly quenched brazing alloys can be prepared from these compositions, and they are suitable for high temperature brazing of steels.

  4. Validation of External Corrosion Growth-Rate Using Polarization Resistance and Soil Properties

    DOT National Transportation Integrated Search

    2010-08-01

    The research project evaluated the use of the Linear Polarization Resistance (LPR) and the Electric Resistance (ER) technologies in estimating the external corrosion growth rates of buried steel pipelines. This was achieved by performing laboratory a...

  5. Corrosion behavior and microstructures of experimental Ti-Au alloys.

    PubMed

    Takahashi, Masatoshi; Kikuchi, Masafumi; Takada, Yukyo; Okuno, Osamu; Okabe, Toru

    2004-06-01

    Anodic polarization was performed in 0.9% NaCl and 1% lactic acid solutions to characterize the relationship between the corrosion behavior and microstructures of cast Ti-Au (5-40%) alloys. An abrupt increase in the current density occurred at approximately 0.6 V vs. SCE for the 30% and 40% Au alloys in the 0.9% NaCl solution. The microstructures after corrosion testing indicated that this breakdown may have been caused by the preferential dissolution of the Ti3Au. However, the potential for preferential dissolution was higher than the breakdown potential of stainless steel or Co-Cr alloy, which meant that the corrosion resistance of the Ti-Au alloys was superior. In 1% lactic acid solution, the corrosion resistance of the Ti-Au alloys was excellent, with no breakdown at any composition. In the present test solutions, the Ti-Au alloys up to 20% Au had good corrosion resistance comparable to that for pure titanium.

  6. Evaluating the effects of hydroxyapatite coating on the corrosion behavior of severely deformed 316Ti SS for surgical implants.

    PubMed

    Mhaede, Mansour; Ahmed, Aymen; Wollmann, Manfred; Wagner, Lothar

    2015-05-01

    The present work investigates the effects of severe plastic deformation by cold rolling on the microstructure, the mechanical properties and the corrosion behavior of austenitic stainless steel (SS) 316Ti. Hydroxyapatite coating (HA) was applied on the deformed material to improve their corrosion resistance. The martensitic transformation due to cold rolling was recorded by X-ray diffraction spectra. The effects of cold rolling on the corrosion behavior were studied using potentiodynamic polarization. The electrochemical tests were carried out in Ringer's solution at 37±1 °C. Cold rolling markedly enhanced the mechanical properties while the electrochemical tests referred to a lower corrosion resistance of the deformed material. The best combination of both high strength and good corrosion resistance was achieved after applying hydroxyapatite coating. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Active-passive corrosion of iron-chromium-nickel alloys in hot concentrated sulphuric acid solutions

    NASA Astrophysics Data System (ADS)

    Kish, Joseph R.

    1999-11-01

    In the manufacture of sulphuric acid more stringent environmental standards and operation economics have forced the industry to improve product utilization, energy efficiency and reliability. A key to improving both the thermal efficiency and reliability is the use and/or development of more corrosion resistance materials including stainless steels, especially in the parts of the plant that handle the condensed acid. Application of more corrosion resistant material requires a better understanding of the corrosion mechanism involved in concentrated H2SO4-H2O (>90 wt.%) solutions. While corrosion kinetics of carbon steel, the traditional material of construction, are relatively well understood, this is much less true in the case of the cyclic active-passive corrosion of stainless steels. Models proposed to explain the cyclic active-passive corrosion involve a periodic formation of either a protective metal sulphate film or an insoluble sulphur layer. To better understand the reactivity and/or passivity of stainless steel in concentrated H2SO4-H2O solutions a study employing immersion and electrochemical techniques, including rotating electrodes, was conducted in order to clarify the following: (1) The state of stainless steel passivity. (2) The conditions in which passivity is stable. (3) The role played by the major alloying elements in establishing and maintaining the passive state. The study involved evaluating the corrosion behaviour of stainless steels S30403 and S43000 along with iron, chromium and nickel in 93.5 wt.% H2SO4 at temperatures between 25--80°C. Major discoveries of the study include: (1) A content of 17--18 wt.% chromium is sufficient to anodically passivate S43000 as the potential is made more noble. Passivity is not stable and requires anodic polarization. (2) Alloyed nickel plays an active role in improving the corrosion resistance of stainless steel. A content of 8 wt.% nickel is sufficient promote a periodic passivation of the base Fe-(17--18)wt.% Cr stainless steel under open-circuit conditions which reduces the corrosion rate by at least an order of magnitude. (3) The electrolysis of concentrated H2SO4-H 2O solutions involves a potential-dependent reduction of H2SO 4 molecules to sulphur-containing species with an oxidation state lower than six (6). The various reduction products have a significant effect on the stainless steel corrosion resistance. (4) Successful modelling of the corrosion of nickel has been accomplished by using a galvanic interaction between a noncontinuous nickel sulphide (NiS) deposit, formed in situ, and the uncovered nickel metal. (5) Successful modelling of the active-passive corrosion of S30403 has been accomplished using a galvanic interaction between NiS(Ni) and S43000.

  8. Electrochemical corrosion testing of fasteners in extracts of treated wood

    Treesearch

    Samuel L. Zelinka; Douglas R. Rammer; Donald S. Stone

    2008-01-01

    A recent change in wood preservatives has highlighted the need for a rapid, quantitative test to measure the corrosion rates of metals in contact with treated wood that could be used to evaluate new fasteners or new wood preservatives. A new method was developed where polarisation resistance tests were conducted on fasteners exposed to a water extract of wood treated...

  9. Titanium Corrosion: Implications For Dental Implants.

    PubMed

    Shah, Rucha; Penmetsa, Deepika Shree Lakshmi; Thomas, Raison; Mehta, Dhoom Singh

    2016-12-01

    Titanium has been considered as one of the most biocompatible metals. Studies testing its corrosion resistance have proposed that the titanium oxide layer formed on the metal surface is lost under certain unavoidable conditions to which it is exposed in the oral environment. This questions its property of corrosion resistance in the oral cavity. Hence, there is a need to understand the mechanisms of corrosion, which can help in the long-term stability and function of implants. Here, we review the possible pathways of corrosion of titanium in the oral cavity, its implications and proposed methods of prevention of corrosion. Copyright© 2016 Dennis Barber Ltd.

  10. Effect of ageing time and temperature on corrosion behaviour of aluminum alloy 2014

    NASA Astrophysics Data System (ADS)

    Gadpale, Vikas; Banjare, Pragya N.; Manoj, Manoranjan Kumar

    2018-03-01

    In this paper, the effect of corrosion behaviour of aluminium alloy 2014 were studied by potentiodynamic polarization in 1 mole of NaCl solution of aged sample. The experimental testing results concluded that, corrosion resistance of Aluminum alloy 2014 degraded with the increasing the temperature (150°C & 200°C) and time of ageing. Corroded surface of the aged specimens was tested under optical microscopes for microstructures for phase analysis. Optical micrographs of corroded surfaces showed general corrosion and pitting corrosion. The corrosion resistance of lower ageing temperature and lower ageing time is higher because of its fine distribution of precipitates in matrix phase.

  11. Erosion-corrosion resistance properties of 316L austenitic stainless steels after low-temperature liquid nitriding

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Pan, Dong

    2018-05-01

    The low-temperature liquid nitriding of stainless steels can result in the formation of a surface zone of so-called expanded austenite (S-phase) by the dissolution of large amounts of nitrogen in the solid solution and formation of a precipitate-free layer supersaturated with high hardness. Erosion-corrosion measurements were performed on low-temperature nitrided and non-nitrided 316L stainless steels. The total erosion-corrosion, erosion-only, and corrosion-only wastages were measured directly. As expected, it was shown that low-temperature nitriding dramatically reduces the degree of erosion-corrosion in stainless steels, caused by the impingement of particles in a corrosive medium. The nitrided 316L stainless steels exhibited an improvement of almost 84% in the erosion-corrosion resistance compared to their non-nitrided counterparts. The erosion-only rates and synergistic levels showed a general decline after low-temperature nitriding. Low-temperature liquid nitriding can not only reduce the weight loss due to erosion but also significantly reduce the weight loss rate of interactions, so that the total loss of material decreased evidently. Therefore, 316L stainless steels displayed excellent erosion-corrosion behaviors as a consequence of their highly favorable corrosion resistances and superior wear properties.

  12. Effects of hydroxyapatite/Zr and bioglass/Zr coatings on morphology and corrosion behaviour of Rex-734 alloy.

    PubMed

    Say, Y; Aksakal, B

    2016-06-01

    To improve corrosion resistance of metallic implant surfaces, Rex-734 alloy was coated with two different bio-ceramics; single-Hydroxyapatite (HA), double-HA/Zirconia(Zr) and double-Bioglass (BG)/Zr by using sol-gel method. Porous surface morphologies at low crack density were obtained after coating and sintering processes. Corrosion characteristics of coatings were determined by Open circuit potential and Potentiodynamic polarization measurements during corrosion tests. Hardness and adhesion strength of coating layers were measured and their surface morphologies before and after corrosion were characterized by scanning electron microscope (SEM), XRD and EDX. Through the SEM analysis, it was observed that corrosion caused degradation and sphere-like formations appeared with dimples on the coated surfaces. The coated substrates that exhibit high crack density, the corrosion was more effective by disturbing and transmitting through the coating layer, produced CrO3 and Cr3O8 oxide formation. It was found that the addition of Zr provided an increase in adhesion strength and corrosion resistance of the coatings. However, BG/Zr coatings had lower adhesion strength than the HA/Zr coatings, but showed higher corrosion resistance.

  13. Preparation and Corrosion Resistance of Trivalent Chromium-Zirconium Composite Coating

    NASA Astrophysics Data System (ADS)

    Huang, J. Z.

    2018-05-01

    Aluminum alloys are widely used in the various industries because of its superior advantages. However there will be a thin oxide layer on the surface of the pure aluminum to inhibit corrosion, when adding some other elements, the obtained aluminum alloy is easy to be corroded. Surface protection is an important means to improve the corrosion resistance of aluminum alloys. The formal research had already confirmed that the trivalent chromium conversion coating can significantly improve the corrosion resistance, and the usage of the zirconium solution can also protect the aluminum alloy from corrosion. In this study, we constructed the binary conversion coating with the Cr2(SO4)3 and the K2ZrF6. The optimum reaction conditions are as follows: 10g/L H3PO4, 2g/L K2ZrF6, 28g/L Cr2(SO4)3, pH=2.5∼3.5, temperature 40°C, and reaction time 10 min. Copper sulfate titration experiment confirmed that the corrosion resistance was significantly improved.

  14. Enhanced antibacterial properties, biocompatibility, and corrosion resistance of degradable Mg-Nd-Zn-Zr alloy.

    PubMed

    Qin, Hui; Zhao, Yaochao; An, Zhiquan; Cheng, Mengqi; Wang, Qi; Cheng, Tao; Wang, Qiaojie; Wang, Jiaxing; Jiang, Yao; Zhang, Xianlong; Yuan, Guangyin

    2015-06-01

    Magnesium (Mg), a potential biodegradable material, has recently received increasing attention due to its unique antibacterial property. However, rapid corrosion in the physiological environment and potential toxicity limit clinical applications. In order to improve the corrosion resistance meanwhile not compromise the antibacterial activity, a novel Mg alloy, Mg-Nd-Zn-Zr (Hereafter, denoted as JDBM), is fabricated by alloying with neodymium (Nd), zinc (Zn), zirconium (Zr). pH value, Mg ion concentration, corrosion rate and electrochemical test show that the corrosion resistance of JDBM is enhanced. A systematic investigation of the in vitro and in vivo antibacterial capability of JDBM is performed. The results of microbiological counting, CLSM, SEM in vitro, and microbiological cultures, histopathology in vivo consistently show JDBM enhanced the antibacterial activity. In addition, the significantly improved cytocompatibility is observed from JDBM. The results suggest that JDBM effectively enhances the corrosion resistance, biocompatibility and antimicrobial properties of Mg by alloying with the proper amount of Zn, Zr and Nd. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. PEM fuel cell bipolar plate material requirements for transportation applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Borup, R.L.; Stroh, K.R.; Vanderborgh, N.E.

    1996-04-01

    Cost effective bipolar plates are currently under development to help make proton exchange membrane (PEM) fuel cells commercially viable. Bipolar plates separate individual cells of the fuel cell stack, and thus must supply strength, be electrically conductive, provide for thermal control of the fuel stack, be a non-porous materials separating hydrogen and oxygen feed streams, be corrosion resistant, provide gas distribution for the feed streams and meet fuel stack cost targets. Candidate materials include conductive polymers and metal plates with corrosion resistant coatings. Possible metals include aluminium, titanium, iron/stainless steel and nickel.

  16. Mesoporous silica nanoparticles for active corrosion protection.

    PubMed

    Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-03-22

    This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g(-1)), narrow pore size distribution (d∼3 nm), and large pore volume (∼1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect.

  17. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    DOEpatents

    Liu, C.T.; McKamey, C.G.; Tortorelli, P.F.; David, S.A.

    1994-06-14

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium. 9 figs.

  18. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    DOEpatents

    Liu, Chain T.; McKamey, Claudette G.; Tortorelli, Peter F.; David, Stan A.

    1994-01-01

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium.

  19. Study of metal corrosion using ac impedance techniques in the STS launch environment

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.

    1989-01-01

    AC impedance measurements were performed to investigate the corrosion resistance of 19 alloys under conditions similar to the STS launch environment. The alloys were: Zirconium 702, Hastelloy C-22, Inconel 625, Hastelloy C-276, Hastelloy C-4, Inconel 600, 7Mo + N, Ferralium 255, Inco Alloy G-3, 20Cb-3, SS 904L, Inconel 825, SS 304LN, SS 316L, SS 317L, ES 2205, SS 304L, Hastelloy B-2, and Monel 400. AC impedance data were gathered for each alloy after one hour immersion time in each of the following three electrolyte solutions: 3.55 percent NaCl, 3.55 percent NaCl-0.1N HCl, and 3.55 percent NaCl-1.0N HCl. The data were analyzed qualitatively using the Nyquist plot and quantitatively using the Bode plot. Polarization resistance, Rp, values were obtained using the Bode plot. Zirconium 702 was the most corrosion resistant alloy in the three electrolytes. The ordering of the other alloys according the their resistance to corrosion varied as the concentration of hydrochloric acid in the electrolyte increased. The corrosion resistance of Zirconium 702 and Ferralium 255 increased as the concentration of hydrochloric acid in the electrolyte increased. The corrosion resistance of the other 17 alloys decreased as the concentration of the hyrdochloric acid in the electrolyte increased.

  20. Use of cyclic current reversal polarization voltammetry for investigating the relationship between corrosion resistance and heat-treatment induced variations in microstructures of 400 C martensitic stainless steels

    NASA Technical Reports Server (NTRS)

    Ambrose, John R.

    1992-01-01

    Software for running a cyclic current reversal polarization voltammagram has been developed for use with a EG&G Princeton Applied Research Model 273 potentiostat/galvanostat system. The program, which controls the magnitude, direction and duration of an impressed galvanostatic current, will produce data in ASCII spreadsheets (Lotus, Quattro) for graphical representation of CCRPV voltammograms. The program was used to determine differences in corrosion resistance of 440 C martenstic stainless steel produced as a result of changes in microstructure effected by tempering. It was determined that tempering at all temperatures above 400 F resulted in increased polarizability of the material, with the increased likelihood that pitting would be initiated upon exposure to marine environments. These results will be used in development of remedial procedures for lowering the susceptibility of these alloys toward the stress corrosion cracking experienced in bearings used in high pressure oxygen turbopumps used in the main engines of space shuttle orbiters.

  1. Detecting Corrosion Resistance of Coated Steel Rebars by Electrochemical Technique (eis)

    NASA Astrophysics Data System (ADS)

    Ryou, J.; Shah, S.

    Electrochemical impedance spectroscopy (EIS) is one of the electrochemical techniques used in materials science. The present measurements are used to evaluate the corrosion resistance of new types of coated steel rebar used in reinforced concrete. In this study, Si-based coating materials are used and evaluated, because adding Si to metals and alloys, including steel, generally increases their corrosion, oxidation, and erosion resistance. The result suggests that electrochemical impedance spectroscopy may be useful for monitoring corrosion activity on coated steel rebars. Based upon impedance changes, it appears that the silicon powder coating bonds well to the steel, and that the coating has a good performance.

  2. Improved corrosion resistance on biodegradable magnesium by zinc and aluminum ion implantation

    NASA Astrophysics Data System (ADS)

    Xu, Ruizhen; Yang, Xiongbo; Suen, Kai Wong; Wu, Guosong; Li, Penghui; Chu, Paul K.

    2012-12-01

    Magnesium and its alloys have promising applications as biodegradable materials, and plasma ion implantation can enhance the corrosion resistance by modifying the surface composition. In this study, suitable amounts of zinc and aluminum are plasma-implanted into pure magnesium. The surface composition, phases, and chemical states are determined, and electrochemical tests and electrochemical impedance spectroscopy (EIS) are conducted to investigate the surface corrosion behavior and elucidate the mechanism. The corrosion resistance enhancement after ion implantation is believed to stem from the more compact oxide film composed of magnesium oxide and aluminum oxide as well as the appearance of the β-Mg17Al12 phase.

  3. 49 CFR 179.400-23 - Operating instructions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-23 Operating instructions. All valves and gages must be clearly identified with corrosion-resistant nameplates. A plate of corrosion-resistant material bearing precautionary instructions for the safe operation...

  4. 49 CFR 179.400-23 - Operating instructions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-23 Operating instructions. All valves and gages must be clearly identified with corrosion-resistant nameplates. A plate of corrosion-resistant material bearing precautionary instructions for the safe operation...

  5. 49 CFR 179.400-23 - Operating instructions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-23 Operating instructions. All valves and gages must be clearly identified with corrosion-resistant nameplates. A plate of corrosion-resistant material bearing precautionary instructions for the safe operation...

  6. 49 CFR 179.400-23 - Operating instructions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-23 Operating instructions. All valves and gages must be clearly identified with corrosion-resistant nameplates. A plate of corrosion-resistant material bearing precautionary instructions for the safe operation...

  7. Development of hydrogen resistant structural alloy NASA-23

    NASA Technical Reports Server (NTRS)

    Bhat, B. N.; Mcpherson, W. B.; Kuruvilla, A. K.; Chen, P. S.; Panda, B.

    1993-01-01

    Hydrogen-resistant alloy NASA-23 was developed specifically as a structural alloy for application in liquid propulsion systems that use hydrogen fuel. NASA-23 was designed to be similar to Alloy 718 in strength, ductility, and corrosion resistance, but with superior resistance to hydrogen environment embrittlement. The alloy is readily processed; it can be both hot and cold worked and is castable and weldable. A material property data base is being generated for both cast and wrought NASA-23. This paper will present the status of alloy development and discuss potential applications in propulsion systems.

  8. Experimental Study of Laser - enhanced 5A03 Aluminum Alloy and Its Stress Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Wang, Guicheng; Chen, Jing; Pang, Tao

    2018-02-01

    Based on the study of improving the stress corrosion resistance of 5A03 aluminum alloy for ship, this paper mainly studied the tensile test, surface morphology and residual stress under laser shock, high temperature and stress corrosion. It is found that the residual compressive stress and the grain refinement on the surface of the material during the heat strengthening process increase the breaking strength of the sample in the stress corrosion environment. Appropriate high temperature maintenance helps to enhance the effect of deformation strengthening. In the 300°C environment insulation, due to recrystallization of the material, the performance decreased significantly. This study provides an experimental basis for effectively improving the stress corrosion resistance of 5A03 aluminum alloy.

  9. Effect of Ni on the corrosion resistance of bridge steel in a simulated hot and humid coastal-industrial atmosphere

    NASA Astrophysics Data System (ADS)

    Li, Dong-liang; Fu, Gui-qin; Zhu, Miao-yong; Li, Qing; Yin, Cheng-xiang

    2018-03-01

    The corrosion resistance of weathering bridge steels containing conventional contents of Ni (0.20wt%, 0.42wt%, 1.50wt%) and a higher content of Ni (3.55wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy-energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low (≤0.42wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher ( 3.55wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe2O2 were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42wt% to 1.50wt%, the corrosion resistance of the bridge steel increased only slightly.

  10. In vitro corrosion resistance of porous NiTi intervertebral fusion devices

    NASA Astrophysics Data System (ADS)

    Schrooten, Jan; Assad, Michel; Van Humbeeck, Jan; Leroux, Michel A.

    2007-02-01

    Porous titanium-nickel (PTN) intervertebral fusion devices, produced by self-propagating high-temperature synthesis, represent an alternative to traditional long-term implants in the orthopaedic field. PTN promotes tissue ingrowth and has succeeded short-term and long-term biocompatibility in vivo testing. In this in vitro study, the PTN morphology was characterized using microfocus computer tomography (μCT) in order to calculate the active PTN surface. Potentiodynamic polarization testing was then performed to evaluate the in vitro corrosion resistance of PTN devices in Hanks' based salt solution. Direct coupling experiments of PTN with Ti6Al4V were also performed in order to establish the galvanic corrosion resistance of PTN intervertebral implants in the presence of potential Ti6Al4V supplemental fixation devices. Compared to the behaviour of other orthopaedic biomaterials and solid NiTi devices, PTN devices showed a level of corrosion resistance that is comparable to other NiTi devices and acceptable for the intended orthopaedic application. Further improvement of the corrosion resistance is still possible by specific electrochemical surface treatments.

  11. Oxidation and corrosion resistance of candidate Stirling engine heater-head-tube alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Barrett, C. A.

    1984-01-01

    Sixteen candidate iron base Stirling engine heater head tube alloys are evaluated in a diesel fuel fired simulator materials test rig to determine their oxidation and corrosion resistance. Sheet specimens are tested at 820 C for 3500 hr in 5 hr heating cycles. Specific weight change data and an attack parameter are used to categorize the alloys into four groups; 10 alloys show excellent for good oxidation and corrosion resistance and six alloys exhibit poor or catastrophic resistance. Metallographic, X-ray, and electron microprobe analyses aid in further characterizing the oxidation and corrosion behavior of the alloys. Alloy compositions, expecially the reactive elements aluminum, titanium, and chromium, play a major role in the excellent oxidation and corrosion behavior of the alloys. The best oxidation resistance is associated with the formation of an iron nickel aluminum outer oxide scale, an intermediate oxide scale rich in chromium and titanium, and an aluminum outer oxide scale adjacent to the metallic substrate, which exhibits a zone of internal oxidation of aluminum and to some extent titanium.

  12. In-vitro biodegradation and corrosion-assisted cracking of a coated magnesium alloy in modified-simulated body fluid.

    PubMed

    Jafari, Sajjad; Singh Raman, R K

    2017-09-01

    A calcium phosphate coating was directly synthesized on AZ91D magnesium (Mg) alloy. Resistance of this coating to corrosion in a modified-simulated body fluid (m-SBF) was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Mechanical properties of the bare and coated alloy were investigated using slow strain rate tensile (SSRT) and fatigue testing in air and m-SBF. Very little is reported in the literature on human-body-fluid-assisted cracking of Mg alloys, viz., resistance to corrosion fatigue (CF) and stress corrosion cracking (SCC). This study has a particular emphasis on the effect of bio-compatible coatings on mechanical and electrochemical degradations of Mg alloys for their applications as implants. The results suggest the coating to improve the general as well as pitting corrosion resistance of the alloy. The coating also provides visible improvement in resistance to SCC, but little improvement in CF resistance. This is explained on the basis of pitting behaviour in the presence and absence of the coating. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Corrosion resistance of a laser spot-welded joint of NiTi wire in simulated human body fluids.

    PubMed

    Yan, Xiao-Jun; Yang, Da-Zhi

    2006-04-01

    The purpose of this study was to investigate corrosion resistance of a laser spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl- concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a laser spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a laser spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a laser spot-welded joint and base metal decreased with increasing of the Cl- concentration and PH value. The improvement of corrosion resistance of the laser spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio. (c) 2005 Wiley Periodicals, Inc.

  14. Evaluation of coated metallic bipolar plates for polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Yoon, Wonseok; Huang, Xinyu; Fazzino, Paul; Reifsnider, Kenneth L.; Akkaoui, Michael A.

    Metallic bipolar plates for polymer electrolyte membrane (PEM) fuel cells typically require coatings for corrosion protection. Other requirements for the corrosion protective coatings include low electrical contact resistance, good mechanical robustness, low material and fabrication cost. The authors have evaluated a number of protective coatings deposited on stainless steel substrates by electroplating and physical vapor deposition (PVD) methods. The coatings are screened with an electrochemical polarization test for corrosion resistance; then the contact resistance test was performed on selected coatings. The coating investigated include Gold with various thicknesses (2 nm, 10 nm, and 1 μm), Titanium, Zirconium, Zirconium Nitride (ZrN), Zirconium Niobium (ZrNb), and Zirconium Nitride with a Gold top layer (ZrNAu). The substrates include three types of stainless steel: 304, 310, and 316. The results show that Zr-coated samples satisfy the DOE target for corrosion resistance at both anode and cathode sides in typical PEM fuel cell environments in the short-term, but they do not meet the DOE contact resistance goal. Very thin gold coating (2 nm) can significantly decrease the electrical contact resistance, however a relatively thick gold coating (>10 nm) with our deposition method is necessary for adequate corrosion resistance, particularly for the cathode side of the bipolar plate.

  15. Silicon carbide as an oxidation-resistant high-temperature material. 1: Oxidation and heat corrosion behavior

    NASA Technical Reports Server (NTRS)

    Schlichting, J.

    1981-01-01

    The oxidation and corrosion behavior of SiC (in the form of a SiC powder) and hot-pressed and reaction-bound material were studied. The excellent stability of SiC in an oxidizing atmosphere is due to the development of protective SiO2 coatings. Any changes in these protective layers (e.g., due to impurities, reaction with corrosive media, high porosity of SiC, etc.) lead in most cases to increased rates of oxidation and thus restrict the field of SiC application.

  16. Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Charlot, L.A.; Westerman, R.E.

    A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allowsmore » its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.« less

  17. Effects of silicon and titanium on the corrosion of low-alloy steels in a simulated coal gasification environment at 600 C

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Soler, J.L.J.; Baxter, D.J.; Norton, J.F.

    1999-12-01

    Results of corrosion tests carried out on a series of Fe-12% Cr alloys in coal gasification environments t 600 C were studied. Effects of Si and Ti on corrosion resistance were assessed using data obtained from a commercial 12% Cr alloy, type 410 (UNS S41000), three specially cast model 12% Cr alloys containing 2.7% Si with Ti levels of 0%, 0.4% and 0.7%, respectively, and a higher alloy (type 28 [UNS N08028]) heat exchanger steel. Corrosion tests were carried out using simulated dry-feed entrained slagging gasifier gas The gas (64% carbon monoxide [CO], 3.8% carbon dioxide [CO{sub 2}], 0.8% hydrogenmore » sulfide [H{sub 2}S], and balance H{sub 2} [in vol%]) was premixed and passed over the test pieces at a rate high enough to prevent thermodynamic equilibrium achievement. Results showed that Si had a strongly beneficial influence on corrosion resistance. Ti, depending upon the amount added, exerted a positive or negative influence on corrosion resistance and reduced problems associated with workability. The kinetics of corrosion were presented in terms of weight-change and metal-loss measurements, the synergistic influences of Si and Ti were discussed, and corrosion resistance was compared with that exhibited by a commercial 12% Cr steel and type 28, the higher alloy material.« less

  18. The influence of external factors on the corrosion resistance of high temperature superconductor thin films against moisture

    NASA Astrophysics Data System (ADS)

    Murugesan, M.; Obara, H.; Yamasaki, H.; Kosaka, S.

    2006-12-01

    High temperature superconductor (HTS) thin films have been systematically investigated for their corrosion resistance against moisture by studying the role of external factors such as temperature (T), relative humidity (RH), and the type of substrates in the corrosion. In general, (i) the corrosion is progressed monotonously with increasing T as well as RH, (ii) a threshold level of water vapor is needed to cause degradation, and (iii) between T and RH, the influence of T is more dominant. HTS films on SrTiO3 and CeO2 buffered sapphire (cbs) substrates showed better corrosion stability and a low rate of degradation in the critical current density as compared to that of the film grown on MgO substrate. Between DyBa2Cu3Oz (DBCO) and YBa2Cu3Oz, the former is reproducibly found to have many fold higher corrosion resistance against moisture. This observed enhancement in the corrosion resistance in DBCO could be explained by the improved microstructure in the films and the better lattice matching with the substrate. Thus, the dual advantage of DBCO/cbs films, i.e., the enhanced corrosion stability of DBCO and the appropriate dielectric properties of sapphire, can be readily exploited for the use of DBCO/cbs films in the microwave and power devices.

  19. Corrosion resistance evaluation of Pd-free Ag-Au-Pt-Cu dental alloys.

    PubMed

    Fujita, Takeshi; Shiraishi, Takanobu; Takuma, Yasuko; Hisatsune, Kunihiro

    2011-01-01

    The corrosion resistance of nine experimental Pd-free Ag-Au-Pt-Cu dental alloys in a 0.9% NaCl solution was investigated using cyclic voltammetry (CV), optical microscopy, and scanning electron microscopy (SEM). CV measurements revealed that the breakdown potential (E(bd)) and zero current potential (E(zc)) increased with increasing Au/(Au+Ag) atomic ratio. Thus, the Au/(Au+Ag) atomic ratio, but not the Cu content, influenced the corrosion resistance of Ag-Au-Pt-Cu alloys. After the forward scan of CV, both optical and scanning electron microscope images showed that in all the experimental alloys, the matrix phase was corroded but not the second phase. From corrosion resistance viewpoint, the Ag-Au-Pt-Cu alloys seemed to be suitable for clinical application.

  20. Microstructure characterization and corrosion resistance properties of Pb-Sb alloys for lead acid battery spine produced by different casting methods.

    PubMed

    Seikh, Asiful H; Sherif, El-Sayed M; Khan Mohammed, Sohail M A; Baig, Muneer; Alam, Mohammad Asif; Alharthi, Nabeel

    2018-01-01

    The aim of this study is to find out the microstructure, hardness, and corrosion resistance of Pb-5%Sb spine alloy. The alloy has been produced by high pressure die casting (HPDC), medium pressure die casting (AS) and low pressure die casting (GS) methods, respectively. The microstructure was characterized by using optical microscopy and scanning electron microscopy (SEM). The hardness was also reported. The corrosion resistance of the spines in 0.5M H2SO4 solution has been analyzed by measuring the weight loss, impedance spectroscopy and the potentiodynamic polarization techniques. It has been found that the spine produced by HPDC has defect-free fine grain structure resulting improvement in hardness and excellent corrosion resistance.

  1. Oxidation and corrosion behavior of modified-composition, low-chromium 304 stainless steel alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Barrett, C. A.

    1977-01-01

    The effects of substituting less strategic elements than Cr on the oxidation and corrosion resistance of AISI 304 stainless steel were investigated. Cyclic oxidation resistance was evaluated at 870 C. Corrosion resistance was determined by exposure of specimens to a boiling copper-rich solution of copper sulfate and sulfuric acid. Alloy substitutes for Cr included Al, Mn, Mo, Si, Ti, V, Y, and misch metal. A level of about 12% Cr was the minimum amount of Cr required for adequate oxidation and corrosion resistance in the modified composition 304 stainless steels. This represents a Cr saving of at least 33%. Two alloys containing 12% Cr and 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified as most promising for more detailed evaluation.

  2. Microstructure characterization and corrosion resistance properties of Pb-Sb alloys for lead acid battery spine produced by different casting methods

    PubMed Central

    Baig, Muneer; Alam, Mohammad Asif; Alharthi, Nabeel

    2018-01-01

    The aim of this study is to find out the microstructure, hardness, and corrosion resistance of Pb-5%Sb spine alloy. The alloy has been produced by high pressure die casting (HPDC), medium pressure die casting (AS) and low pressure die casting (GS) methods, respectively. The microstructure was characterized by using optical microscopy and scanning electron microscopy (SEM). The hardness was also reported. The corrosion resistance of the spines in 0.5M H2SO4 solution has been analyzed by measuring the weight loss, impedance spectroscopy and the potentiodynamic polarization techniques. It has been found that the spine produced by HPDC has defect-free fine grain structure resulting improvement in hardness and excellent corrosion resistance. PMID:29668709

  3. Pitting corrosion resistance of a novel duplex alloy steel in alkali-activated slag extract in the presence of chloride ions

    NASA Astrophysics Data System (ADS)

    Shi, Jin-jie; Ming, Jing; Liu, Xin

    2017-10-01

    In this study, two types of reinforcing steels (conventional low-carbon steel and a novel duplex alloy steel with Cr and Mo) were exposed to chloride-contaminated extract solutions (ordinary Portland cement (OPC) extract and alkali-activated slag (AAS) extract) to investigate their pitting corrosion resistance. The results confirm that the pitting corrosion resistance of the alloy steel is much higher than that of the low-carbon steel in both extract solutions with various NaCl concentrations. Moreover, for each type of steel, the AAS extract contributes to a higher pitting corrosion resistance compared with the OPC extract in the presence of chloride ions, likely because of the formation of flocculent precipitates on the steel surface.

  4. Optimization of Oxidation Temperature for Commercially Pure Titanium to Achieve Improved Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Bansal, Rajesh; Singh, J. K.; Singh, Vakil; Singh, D. D. N.; Das, Parimal

    2017-03-01

    Thermal oxidation of commercially pure titanium (cp-Ti) was carried out at different temperatures, ranging from 200 to 900 °C to achieve optimum corrosion resistance of the thermally treated surface in simulated body fluid. Scanning electron microscopy, x-ray diffraction, Raman spectroscopy and electrochemical impedance spectroscopy techniques were used to characterize the oxides and assess their protective properties exposed in the test electrolyte. Maximum resistance toward corrosion was observed for samples oxidized at 500 °C. This was attributed to the formation of a composite layer of oxides at this temperature comprising Ti2O3 (titanium sesquioxide), anatase and rutile phases of TiO2 on the surface of cp-Ti. Formation of an intact and pore-free oxide-substrate interface also improved its corrosion resistance.

  5. The Performance of Dammar-based Paint System Evaluated by Electrochemical Impedance Spectroscopy (EIS) and Potential Time Measurement (PTM)

    NASA Astrophysics Data System (ADS)

    Omar, N. M.; Ahmad, A. Hanom

    2009-06-01

    The coating resistance of the Dammar-based paint system was determined by using Electrochemical Impedance Spectroscopy (EIS), whereas, the corrosion potential analysis was determined by using potential time measurement (PTM) method. Carotenoid pigment obtained from Capsicum Annum (dried chili pepper) was added into the mixture of dammar and acrylic polyol resin and the paint systems were proofed on Aluminium steel Q-panels as a substrate. Result shows that the paint system with a composition of 35% dammar (CD35%) possessed the higher corrosion resistance after 30 days of exposure in 3% NaCl solution for electrochemical impedance spectroscopy and also can withstand the longest time for delimitation protection in PTM analysis. The results prove that the developed organic paint system can improve the electrochemical and corrosion protection properties of a paint system.

  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. Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part 1: The Protective Scale

    NASA Astrophysics Data System (ADS)

    Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

    2015-09-01

    Coarse-grained Fe-based oxide dispersion-strengthened (ODS) steels are a class of advanced materials for combined cycle gas turbine systems to deal with operating temperatures and pressures of around 1100°C and 15-30 bar in aggressive environments, which would increase biomass energy conversion efficiencies up to 45% and above. This two-part paper reports the possibility of the development of simultaneous corrosion barrier and optimized microstructure in a FeCrAl heat-resistant alloy for energy applications. The first part reports the mechanism of generating a dense, self-healing α-alumina layer by thermal oxidation, during a heat treatment that leads to a coarse-grained microstructure with a potential value for high-temperature creep resistance in a FeCrAl ODS ferritic alloy, which will be described in more detail in the second part.

  8. The Effect of Homogenization on the Corrosion Behavior of Al-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Li, Yin; Hung, Yuanchun; Du, Zhiyong; Xiao, Zhengbing; Jia, Guangze

    2018-04-01

    The effect of homogenization on the corrosion behavior of 5083-O aluminum alloy is presented in this paper. The intergranular corrosion and exfoliation corrosion were used to characterize the discussed corrosion behavior of 5083-O aluminum alloy. The variations in the morphology, the kind and distribution of the precipitates, and the dislocation configurations in the samples after the homogenization were evaluated using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The effects of the highly active grain boundary character distribution and the types of constituent particles on the corrosion are discussed on the basis of experimental observations. The results indicated that the corrosion behavior of 5083-O alloy was closely related to the microstructure obtained by the heat treatment. Homogenization carried out after casting had the optimal effect on the overall corrosion resistance of the material. Nevertheless, all samples could satisfy the requirements of corrosion resistance in marine applications.

  9. Corrosion resistance and in-vitro bioactivity of BaO containing Na2O-CaO-P2O5 phosphate glass-ceramic coating prepared on 316 L, duplex stainless steel 2205 and Ti6Al4V

    NASA Astrophysics Data System (ADS)

    Edathazhe, Akhila B.; Shashikala, H. D.

    2018-03-01

    The phosphate glass with composition 11Na2O-15BaO-29CaO-45P2O5 was coated on biomedical implant materials such as stainless steel 316 L, duplex stainless steel (DSS) 2205 and Ti6Al4V alloy by thermal enamelling method. The structural properties and composition of glass coated substrates were studied by x-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive x-ray spectroscopy (EDS) analysis. The coatings were partially crystalline in nature with porous structure and pore size varied from micro to nanometer range. The polarization curve was obtained for uncoated and coated substrates from electrochemical corrosion test which was conducted at 37 °C in Hank’s balanced salt solution (HBSS). The corrosion resistance of 316 L substrate increased after coating, whereas it decreased in case of DSS 2205 and Ti6Al4V. The XRD and SEM/EDS studies indicated the bioactive hydroxyapatite (HAp) layer formation on all the coated surfaces after electrochemical corrosion test, which improved the corrosion resistance. The observed electrochemical corrosion behavior can be explained based on protective HAp layer formation, composition and diffusion of ions on glass coated surfaces. The in-vitro bioactivity test was carried out at 37 °C in HBS solution for 14 days under static conditions for uncoated and coated substrates. pH and ion release rate measurements from the coated samples were conducted to substantiate the electrochemical corrosion test. The lower ion release rates of Na+ and Ca2+ from coated 316 L supported its higher electrochemical corrosion resistance among coated samples. Among the uncoated substrates, DSS showed higher electrochemical corrosion resistance. Amorphous calcium-phosphate (ACP) layer formation on all the coated substrates after in-vitro bioactivity test was confirmed by XRD, SEM/EDS and ion release measurements. The present work is a comparative study of corrosion resistance and bioactivity of glass coated and uncoated biomedical implants such as 316 L, DSS and Ti6Al4V.

  10. Surface modification of a biodegradable magnesium alloy with phosphorylcholine (PC) and sulfobetaine (SB) functional macromolecules for reduced thrombogenicity and acute corrosion resistance.

    PubMed

    Ye, Sang-Ho; Jang, Yong-Seok; Yun, Yeo-Heung; Shankarraman, Venkat; Woolley, Joshua R; Hong, Yi; Gamble, Lara J; Ishihara, Kazuhiko; Wagner, William R

    2013-07-02

    Siloxane functionalized phosphorylcholine (PC) or sulfobetaine (SB) macromolecules (PCSSi or SBSSi) were synthesized to act as surface modifying agents for degradable metallic surfaces to improve acute blood compatibility and slow initial corrosion rates. The macromolecules were synthesized using a thiol-ene radical photopolymerization technique and then utilized to modify magnesium (Mg) alloy (AZ31) surfaces via an anhydrous phase deposition of the silane functional groups. X-ray photoelectron spectroscopy surface analysis results indicated successful surface modification based on increased nitrogen and phosphorus or sulfur composition on the modified surfaces relative to unmodified AZ31. In vitro acute thrombogenicity assessment after ovine blood contact with the PCSSi and SBSSi modified surfaces showed a significant decrease in platelet deposition and bulk phase platelet activation compared with the control alloy surfaces. Potentiodynamic polarization and electrochemical impedance spectroscopy data obtained from electrochemical corrosion testing demonstrated increased corrosion resistance for PCSSi- and SBSSi-modified AZ31 versus unmodified surfaces. The developed coating technique using PCSSi or SBSSi showed promise in acutely reducing both the corrosion and thrombotic processes, which would be attractive for application to blood contacting devices, such as vascular stents, made from degradable Mg alloys.

  11. Effect of thermal treatment on the bio-corrosion and mechanical properties of ultrafine-grained ZK60 magnesium alloy.

    PubMed

    Choi, H Y; Kim, W J

    2015-11-01

    The combination of solid solution heat treatments and severe plastic deformation by high-ratio differential speed rolling (HRDSR) resulted in the formation of an ultrafine-grained microstructure with high thermal stability in a Mg-5Zn-0.5Zr (ZK60) alloy. When the precipitate particle distribution was uniform in the matrix, the internal stresses and dislocation density could be effectively removed without significant grain growth during the annealing treatment (after HRDSR), leading to enhancement of corrosion resistance. When the particle distribution was non-uniform, rapid grain growth occurred in local areas where the particle density was low during annealing, leading to development of a bimodal grain size distribution. The bimodal grain size distribution accelerated corrosion by forming a galvanic corrosion couple between the fine-grained and coarse-grained regions. The HRDSR-processed ZK60 alloy with high thermal stability exhibited high corrosion resistance, high strength and high ductility, and excellent superplasticity, which allow the fabrication of biodegradable magnesium devices with complicated designs that have a high mechanical integrity throughout the service life in the human body. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. The effects of different bending techniques on corrosion resistance and nickel release of superelastic orthodontic NiTi archwires

    NASA Astrophysics Data System (ADS)

    Rujeerapaiboon, N.; Anuwongnukroh, N.; Dechkunakorn, S.; Jariyaboon, M.

    2017-04-01

    Bending superelastic NiTi archwire is indicated in some stages of orthodontic treatment. The difference in bending techniques may affect corrosion resistance and nickel release. The purpose of this study was to investigate the corrosion resistance and nickel release after different bending techniques of NiTi archwires. Preform-curved NiTi archwires were used as a template for bending and used as a control group. 0.016×0.022 inches superelastic NiTi archwires were bent to curve-shape by cold bending, DERHT bending and cold bending then DERHT technique. Potentiodynamic polarization technique was used to measure corrosion behavior of the wires. Corrosion potential (ECORR), corrosion density (ICORR), and breakdown potential of each wire were determined. In addition, the amount of nickel release in the solution after the test was inductively coupled plasma mass spectrometry (ICP-MS). Although, the results showed that ECORR and ICORR were not statistically significantly different among all groups, the difference in breakdown potential and nickel release were observed. Similar corrosion resistance and nickel release were presented in the preform-curved NiTi archwires, cold bending, and cold bending then DERHT group. The DERHT bending group showed the lowest breakdown potential and highest nickel release.

  13. Effect of Annealing on the Passive Film Stability and Corrosion Resistance of New Families of Iron-Based Amorphous Metals

    DTIC Science & Technology

    2011-06-01

    metallic glass easier to create and more stable once formed, thus improving the corrosion resistance. Adding titanium will enable the formation of...glass easier to create and more stable once formed, thus improving the corrosion resistance. Adding titanium will enable the formation of an extremely...research, it was hypothesized that additions of titanium could enable the formation of a protective titanium oxide film on the surface of the alloy

  14. Corrosion resistance of NiTi in fluoride and acid environments.

    PubMed

    Benyahia, Hicham; Ebntouhami, Mohamed; Forsal, Issam; Zaoui, Fatima; Aalloula, Elhoussine

    2009-12-01

    The aim of our study was to assess in the laboratory the electrochemical behavior of nickel-titanium alloy (NiTi) by simulating the aggressive conditions found in the mouth (notably fluoride and acidity) in order to determine its biocompatibility. The impact of fluoride and pH acid on the corrosion resistance of orthodontic NiTi was studied using classic electrochemical measurement techniques including follow-up over time of the corrosion potential, polarization measurements and impedance spectroscopy. In addition, scanning electron microscopy was used to evaluate the status of the alloy surface before and after immersion in the different media. The results demonstrated the particularly low corrosion resistance of NiTi alloy in the presence of fluorides. In an acidic environment, the alloy showed greater resistance thanks to the passivation phenomenon. The synergistic action of fluoride and ph Acid on NiTi corrosion was not clearly demonstrated. Copyright 2009 Collège Européen d'Orthodontie. Published by Elsevier Masson SAS.. All rights reserved.

  15. Electrochemical behavior and corrosion resistance of Ti-15Mo alloy in naturally-aerated solutions, containing chloride and fluoride ions.

    PubMed

    Rodrigues, A V; Oliveira, N T C; dos Santos, M L; Guastaldi, A C

    2015-01-01

    The electrochemical behavior and corrosion resistance of Ti-15Mo alloy to applications as biomaterials in solutions 0.15 mol L(-1) Ringer, 0.15 mol L(-1) Ringer plus 0.036 mol L(-1) NaF and 0.036 mol L(-1) NaF (containing 1,500 ppm of fluoride ions, F(-)) were investigated using open-circuit potential, cyclic voltammetry, and electrochemical impedance spectroscopy techniques, X-ray photoelectron spectroscopy and scanning electron microscope. Corrosion resistance and electrochemical stability of the Ti-15Mo alloy decreased in solutions containing F(-) ions. In all cases, there were formation and growth of TiO2 and MoO3 (a protector film), not being observed pitting corrosion, which might enable Ti-15Mo alloys to be used as biomedical implant, at least in the studied conditions, since the electrochemical stability and corrosion resistance of the passive films formed are necessary conditions for osseointegration.

  16. Study on the corrosion properties of nanocrystalline nickel electrodepositied by reverse pulse current

    NASA Astrophysics Data System (ADS)

    Cheng, Wen; Ge, Wen; Yang, Qian; Qu, Xinxin

    2013-07-01

    Nanocrystalline nickel coatings were produced by the method of reverse pulse electrodepositing on the surface of steel sheets. The crystallite size of nanocrystalline nickel coatings was determined by X-ray diffraction (XRD). The effect of saccharin concentration on the crystallite size of the coatings was studied. The average crystallite sizes were diminished as a result of increasing saccharin concentration. CHI660C electrochemical workstation was used to determine the Tafel polarization curves and electrochemical impedance spectroscopy (EIS) of the coatings. The value of corrosion potential, natural corrosion current density, polarizaiton resistance and impedance was calculated, the results suggested that smaller grain size led to higher polarization resistance. EIS gave the charge transfer resistance Rct and pore resistance Rpo variation trend from beginning to 30 min. Scanning electron microscopy (SEM) examination showed the surface morphology of the nickel coatings after the neutral salt spray (NSS) test or bathing in 10% HCl. The images indicated that the corrosion behavior of nanocrystalline nickel coatings was pitting corrosion, the mechanism was also discussed.

  17. An evaluation of carbon steel corrosion under stagnant seawater conditions.

    PubMed

    Lee, Jason S; Ray, Richard I; Lemieux, Edward J; Falster, Alexander U; Little, Brenda J

    2004-01-01

    Corrosion of 1020 carbon steel coupons in natural seawater over a 1-year period was more aggressive under strictly anaerobic stagnant conditions than under aerobic stagnant conditions as measured by weight loss and instantaneous corrosion rate (polarization resistance). Under oxygenated conditions, a two-tiered oxide layer of lepidocrocite/goethite formed. The inner layer was extremely tenacious and resistant to acid cleaning. Under anaerobic conditions, the corrosion product was initially a non-tenacious sulphur-rich corrosion product, mackinawite, with enmeshed bacteria. As more sulphide was produced the mackinawite was transformed to pyrrhotite. In both aerobic and anaerobic exposures, corrosion was more aggressive on horizontally oriented coupons compared to vertically oriented samples.

  18. Wear and corrosion resistance of electroforming layer after WEDM for 7075 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Xu, Jinkai; Qiu, Rongxian; Lian, Zhongxu; Yu, Zhanjiang; Yu, Peng; Ren, Wanfei; Yu, Huadong

    2018-06-01

    In order to investigate the influence of the recast layer obtained by wire electrical discharge machining (WEDM) for 7075 aluminum alloy on the mechanical physical properties of the workpiece, we carried out research on the geometry parameters, microstructure, adhesion, wear resistance and corrosion resistance of the recast layer. The results show that the unit thermal power density decreases, the surface roughness Ra value increases, and the amount of the electric erosion craters and the micro/nano pits decrease with the increase of current and voltage. In the meantime, the thickness and hardness of the recast layer are increased, so the wear resistance and corrosion resistance are significantly improved. In addition, the surface hardness plays a major role in increasing wear resistance.

  19. 46 CFR 162.028-3 - Requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... a normal fashion; (ii) Any coating required in this section to be corrosion resistant must remain... hours. The gauge shall be constructed of corrosion-resistant materials, so that the pointer or face...

  20. 46 CFR 162.028-3 - Requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... a normal fashion; (ii) Any coating required in this section to be corrosion resistant must remain... hours. The gauge shall be constructed of corrosion-resistant materials, so that the pointer or face...

  1. Stress corrosion cracking of several high strength ferrous and nickel alloys

    NASA Technical Reports Server (NTRS)

    Nelson, E. E.

    1971-01-01

    The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

  2. Composite polymer-containing coatings on Mg alloys perspective for industry and implant surgery

    NASA Astrophysics Data System (ADS)

    Gnedenkov, S. V.; Sinebryukhov, S. L.; Mashtalyar, D. V.; Imshinetskiy, I. M.; Gnedenkov, A. S.; Minaev, A. N.

    2017-09-01

    In order to improve the corrosion resistance of magnesium alloys the ways of composite protective coating formation were developed by means of plasma electrolytic oxidation (PEO) as well as electrophoretic deposition methods. Electrochemical, corrosion, tribological, and morphological properties of the MAS magnesium alloy composite coatings were studied. The composite polymer-containing coating decrease the corrosion current density values by three orders of magnitude (Ic = 2.0 . 10-10 A/cm2), in comparison with the base PEO-layer. These polymer-containing layers enable one to expand the practical usage area of Mg alloys. The application of such coatings provides the increasing the bioactivity and regulate the corrosion rate of resorbable magnesium implants.

  3. In vitro studying corrosion behavior of porous titanium coating in dynamic electrolyte.

    PubMed

    Chen, Xuedan; Fu, Qingshan; Jin, Yongzhong; Li, Mingtian; Yang, Ruisong; Cui, Xuejun; Gong, Min

    2017-01-01

    Porous titanium (PT) is considered as a promising biomaterials for orthopedic implants. Besides biocompatibility and mechanical properties, corrosion resistance in physiological environment is the other important factor affecting the long stability of an implant. In order to investigate the corrosion behavior of porous titanium implants in a dynamic physiological environment, a dynamic circle system was designed in this study. Then a titanium-based implant with PT coating was fabricated by plasma spraying. The corrosion resistance of PT samples in flowing 0.9% NaCl solution was evaluated by electrochemical measurements. Commercial pure solid titanium (ST) disc was used as a control. The studies of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) show that the pores in the PT play a negetive part in corrosion resistance and the flowing electrolyte can increase the corrosive rate of all titanium samples. The results suggest that pore design of titanium implants should pay attention to the effect of dynamic process of a physiological environment on the corrosion behavior of implants. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. 49 CFR 193.2627 - Atmospheric corrosion control.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Atmospheric corrosion control. 193.2627 Section... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2627 Atmospheric corrosion... atmospheric corrosion by— (a) Material that has been designed and selected to resist the corrosive atmosphere...

  5. An electrochemical approach to development of a method for accele strength evaluation of hard tissue replacement materials

    NASA Astrophysics Data System (ADS)

    Lee, Byung Jun; Kim, Min Gun

    2003-04-01

    To develop a method of accelerating the strength evaluation of hard tissue replacement materials (Ti-6Al-4V alloy) with an electrochemical approach in the short term, corrosion tests were carried out on Ti-6Al-4V alloy) by means of applying a uniform current to a simulated physiological environment and the potental difference was scanned to check the variations in the resistance of the specimens. As a result, the corrosion behavior was monitored by scanning the potential difference and an empirical formula for controlling the corrosion behavior of the Ti-6Al-4V alloy in the simulated physiological environment was proposed.

  6. PPM-based System for Guided Waves Communication Through Corrosion Resistant Multi-wire Cables

    NASA Astrophysics Data System (ADS)

    Trane, G.; Mijarez, R.; Guevara, R.; Pascacio, D.

    Novel wireless communication channels are a necessity in applications surrounded by harsh environments, for instance down-hole oil reservoirs. Traditional radio frequency (RF) communication schemes are not capable of transmitting signals through metal enclosures surrounded by corrosive gases and liquids. As an alternative to RF, a pulse position modulation (PPM) guided waves communication system has been developed and evaluated using a corrosion resistant 4H18 multi-wire cable, commonly used to descend electronic gauges in down-hole oil applications, as the communication medium. The system consists of a transmitter and a receiver that utilizes a PZT crystal, for electrical/mechanical coupling, attached to each extreme of the multi-wire cable. The modulator is based on a microcontroller, which transmits60 kHz guided wave pulses, and the demodulator is based on a commercial digital signal processor (DSP) module that performs real time DSP algorithms. Experimental results are presented, which were obtained using a 1m corrosion resistant 4H18multi-wire cable, commonly used with downhole electronic gauges in the oil sector. Although there was significant dispersion and multiple mode excitations of the transmitted guided wave energy pulses, the results show that data rates on the order of 500 bits per second are readily available employing PPM and simple communications techniques.

  7. Preparation and corrosion resistance of electroless Ni-P/SiC functionally gradient coatings on AZ91D magnesium alloy

    NASA Astrophysics Data System (ADS)

    Wang, Hui-Long; Liu, Ling-Yun; Dou, Yong; Zhang, Wen-Zhu; Jiang, Wen-Feng

    2013-12-01

    In this paper, the protective electroless Ni-P/SiC gradient coatings on AZ91D magnesium alloy substrate were successfully prepared. The prepared Ni-P/SiC gradient coatings were characterized for its microstructure, morphology, microhardness and adhesion to the substrate. The deposition reaction kinetics was investigated and an empirical rate equation for electroless Ni-P/SiC plating on AZ91D magnesium alloy was developed. The anticorrosion properties of the Ni-P/SiC gradient coatings in 3.5 wt.% NaCl solution were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies. The potentiodynamic polarization measurements revealed that the SiC concentration in the bath and heat treatment can influence the corrosion protection performance of electroless deposited Ni-P/SiC gradient coatings. EIS studies indicated that higher charge transfer resistance and slightly lower capacitance values were obtained for Ni-P/SiC gradient coatings compared to Ni-P coatings. The corrosion resistance of the Ni-P/SiC gradient coatings increases initially and decreases afterwards with the sustained increasing of immersion time in the aggressive medium. The electroless Ni-P/SiC gradient coatings can afford better corrosion protection for magnesium alloy substrate compared with Ni-P coatings.

  8. Corrosion Resistance of a Cast-Iron Material Coated With a Ceramic Layer Using Thermal Spray Method

    NASA Astrophysics Data System (ADS)

    Florea, C. D.; Bejinariu, C.; Munteanu, C.; Istrate, B.; Toma, S. L.; Alexandru, A.; Cimpoesu, R.

    2018-06-01

    Cast-iron 250 used for breake systems present many corrosion signs after a mean usage time based on the environment conditions they work. In order to improve them corrosion resistance we propose to cover the active part of the material using a ceramic material. The deposition process is an industrial deposition system based on thermal spraying that can cover high surfaces in low time. In this articol we analyze the influence of a ceramic layer (40-50 µm) on the corrosion resistance of FC250 cast iron. The results were analyzed using scanning electron microscopy (SEM), X-ray energy dispersive (EDS) and linear and cyclic potentiometry.

  9. Advanced heat exchanger development for molten salts

    DOE PAGES

    Sabharwall, Piyush; Clark, Denis; Glazoff, Michael; ...

    2014-12-01

    This study addresses present work concerned with advanced heat exchanger development for molten salt in nuclear and non nuclear thermal systems. The molten salt systems discussed herein use alloys, such as Hastelloy N and 242, which show corrosion resistance to molten salt at nominal operating temperatures up to 700°C. These alloys were diffusion welded, and the corresponding information is presented. Test specimens were prepared for exposing diffusion welds to molten salt environments. Hastelloy N and 242 were found to be weldable by diffusion welding, with ultimate tensile strengths about 90% of base metal values. Both diffusion welds and sheet materialmore » in Hastelloy N were corrosion tested in?58 mol% KF and 42 mol% ZrF4 at 650, 700, and 850°C for 200, 500, and 1,000 hours. Corrosion rates found were similar between welded and nonwelded materials, typically <10 mils per year. For materials of construction, nickel and alloys with dense nickel coatings are effectively inert to corrosion in fluorides, but not so in chlorides. Hence, additional testing of selected alloys for resistance to intergranular corrosion is needed, as is a determination of corrosion rate as a function of contaminant type and alloy composition with respect to chromium and carbon to better define the optimal chromium and carbon composition, independent of galvanic or differential solubility effects. Also presented is the division of the nuclear reactor and high temperature components per ASME standards, along with design requirements for a subcritical Rankine power cycle heat exchanger that has to overcome pressure difference of about 17 MPa.« less

  10. Electrochemical Corrosion Properties of Commercial Ultra-Thin Copper Foils

    NASA Astrophysics Data System (ADS)

    Yen, Ming-Hsuan; Liu, Jen-Hsiang; Song, Jenn-Ming; Lin, Shih-Ching

    2017-08-01

    Ultra-thin electrodeposited Cu foils have been developed for substrate thinning for mobile devices. Considering the corrosion by residual etchants from the lithography process for high-density circuit wiring, this study investigates the microstructural features of ultra-thin electrodeposited Cu foils with a thickness of 3 μm and their electrochemical corrosion performance in CuCl2-based etching solution. X-ray diffraction and electron backscatter diffraction analyses verify that ultra-thin Cu foils exhibit a random texture and equi-axed grains. Polarization curves show that ultra-thin foils exhibit a higher corrosion potential and a lower corrosion current density compared with conventional (220)-oriented foils with fan-like distributed fine-elongated columnar grains. Chronoamperometric results also suggest that ultra-thin foils possess superior corrosion resistance. The passive layer, mainly composed of CuCl and Cu2O, forms and dissolves in sequence during polarization.

  11. Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium

    NASA Astrophysics Data System (ADS)

    Ravi Shankar, A.; Mathiya, S.; Thyagarajan, K.; Kamachi Mudali, U.

    2010-07-01

    Pyrochemical reprocessing in molten chloride salt medium has been considered as one of the best options for the reprocessing of spent metallic fuels of future fast breeder reactors. The unit operations such as salt preparation, electrorefining, and cathode processing involve the presence of molten LiCl-KCl eutectic salt from 673 to 1373 K (400 to 1100 °C). The present work discusses the corrosion behavior of electroformed nickel (EF Ni) without and with nickel-tungsten (Ni-W) coating, 316L SS, and INCONEL 625 alloy in molten LiCl-KCl eutectic salt at 673 K, 773 K, and 873 K (400 °C, 500 °C, and 600 °C) in the presence of air. The weight percent loss of the exposed samples was determined by the weight loss method and surface morphology of the salt exposed, and product layers were examined by scanning electron microscopy (SEM). X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were also carried out on the exposed and corrosion product layers to understand the phases present and the corrosion mechanism involved. The results of the present study indicated that INCONEL 625 alloy showed superior corrosion resistance compared to electroformed nickel (EF Ni), EF Ni with nickel-tungsten (Ni-W) coating (EF Ni-W), and 316L SS. The EF Ni with Ni-W coating exhibits better corrosion resistance than EF Ni without tungsten coating. Based on the surface morphology, XRD, and EDX analysis of corrosion product layers, the mechanism of corrosion of INCONEL 625 and 316L involves formation of chromium-rich compound at the surface and subsequent spallation. For the EF Ni, the porous thick NiO corrosion product allows the penetration of salt, thus accelerating the corrosion. Improved corrosion resistance of EF Ni-W was attributed to the W-rich NiO layer, while for INCONEL 625, the adherent and protective NiO layer improved the corrosion resistance. The article highlights the results of the present investigation.

  12. Effect of the layer of anodized 7075-T6 aluminium corrosion properties

    NASA Astrophysics Data System (ADS)

    Montoya Z, R. D.; L, E. Vera; Pineda T, Y.; Cedeño, M. L.

    2017-01-01

    Aluminium alloys are widely used in various sectors of industry. The 7075-T6 alloy corresponding to an Al-Zn T6, is mostly used as structural component in the aviation industry, due to the good relationship between weight and mechanical properties. However, the negative point of this alloys is the resistance to corrosion, which is why they need to be coated with an anodic film. Different surface treatments, such as anodizing, are used to improve corrosion resistance. Anodizing is an electrolytic process by which a protective layer on aluminium known as “alumina” is formed, this is formed by the passage of an electric current in an acidic electrolyte. This investigation presents a study of the effect of the thickness of layers of alumina deposited by anodized method, in the corrosion resistance of 7075-T6 aluminium. This study was performed by using in a solution of tartaric acid - sulfuric acid and an inorganic salt. To evaluate the influence alumina layer thickness on the corrosion properties some tests were carried out by using the electrochemical spectroscopy impedances (EIS) technique and Tafel polarization curves. It was found that the grown of the thickness of film favourably influences in the corrosion resistance.

  13. Wear and corrosion resistance of laser-cladded Fe-based composite coatings on AISI 4130 steel

    NASA Astrophysics Data System (ADS)

    Fan, Li; Chen, Hai-yan; Dong, Yao-hua; Dong, Li-hua; Yin, Yan-sheng

    2018-06-01

    The wear and corrosion resistance of Fe72.2Cr16.8Ni7.3Mo1.6Mn0.7C0.2Si1.2 and Fe77.3Cr15.8Ni3.9Mo1.1Mn0.5C0.2Si1.2 coatings laser-cladded on AISI 4130 steel were studied. The coatings possess excellent wear and corrosion resistance despite the absence of expensive yttrium, tungsten, and cobalt and very little molybdenum. The microstructure mainly consists of dendrites and eutectic phases, such as duplex (γ+α)-Fe and the Fe-Cr (Ni) solid solution, confirmed via energy dispersive spectrometry and X-ray diffraction. The cladded Fe-based coatings have lower coefficients of friction, and narrower and shallower wear tracks than the substrate without the cladding, and the main wear mechanism is mild abrasive wear. Electrochemical test results suggest that the soft Fe72.2Cr16.8Ni7.3Mo1.6Mn0.7C0.2Si1.2 coating with high Cr and Ni concentrations has high passivation resistance, low corrosion current, and positive corrosion potential, providing a better protective barrier layer to the AISI 4130 steel against corrosion.

  14. Evaluation of corrosion resistance of microalloyed reinforcing steel

    DOT National Transportation Integrated Search

    2004-02-01

    The corrosion resistance of three microalloyed steels and two conventional reinforcing steels in concrete was evaluated. The microalloyed steels contain concentrations of chromium, copper, and phosphorus that, while low, are significantly higher than...

  15. Passivation Behavior of Fe-Based Amorphous Coatings Prepared by High-Velocity Air/Oxygen Fuel Processes

    NASA Astrophysics Data System (ADS)

    Ma, H. R.; Li, J. W.; Chang, C. T.; Wang, X. M.; Li, R. W.

    2017-12-01

    Corrosion resistance and passivation behavior of Fe63Cr8Mo3.5Ni5P10B4C4Si2.5 amorphous coatings prepared by the activated combustion high-velocity air fuel (AC-HVAF) and high-velocity oxygen fuel (HVOF) processes have been studied in detail by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, cathodic polarization and Mott-Schottky approach. The AC-HVAF coating shows higher corrosion resistance than the HVOF coating in 3.5 wt.% NaCl solution, as evidenced by its lower corrosion current density and passive current density. It is found that the superior corrosion resistance of the AC-HVAF coating is attributed to the enhanced formation of a dense passive film with less defective structure, higher pitting resistance and passivity stability, as well as stronger repassivity.

  16. Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel.

    PubMed

    Song, Sol-Ji; Kim, Jung-Gu

    2018-01-20

    This study examined the synergic effect of alloying the element Cr and the environmental element Mg 2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) tests and weight-loss tests. The Mg 2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg 2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe₂O₄ and a mixed layer (Cr oxide + FeCr₂O₄ + MgCr₂O₄) improved the corrosion resistance of the low-alloy steel in the seawater.

  17. Corrosion sealing of amalgam restorations in vitro.

    PubMed

    Mahler, David B; Pham, Bao V; Adey, Jerry D

    2009-01-01

    Amalgam restorations, when first placed, have been shown to exhibit a gap at the amalgam/tooth interface. With time in service, this gap fills with corrosion products that have the potential to "seal" the restoration. With the advent of high-copper, more corrosion-resistant amalgams, there has been concern that the time required to create this seal would be increased significantly when compared with low-copper traditional amalgams. The current study was designed to address this concern. Amalgam was condensed into a MACOR mold, simulating a Class I cavity form and then immersed into a 1.0% NaCl solution to simulate oral conditions. Using an air pressure test, the sealing was monitored over time. The results showed that the sealing was influenced by the size of the initial gap prior to immersion as well as corrosion resistance of the amalgam and that a corrosion-resistant amalgam with a small initial gap size can seal as quickly as a corrosion-prone amalgam. Therefore, it is not possible to predict sealing behavior based on corrosion resistance, alone. Furthermore, the presence of zinc in the amalgam alloy has been shown to result in the formation of zinc corrosion products in the amalgam/mold margin, which contributes to more rapid sealing. Analysis of a tooth extracted after 16 years of clinical service that had been restored with an amalgam-containing zinc was also shown to contain zinc corrosion products in the occlusal marginal area. This could explain the reported reduction in marginal fracture of clinically placed amalgam restorations made from zinc-containing alloys.

  18. Effect of Different Cooling Rates on the Corrosion Behavior of High-Carbon Pearlitic Steel

    NASA Astrophysics Data System (ADS)

    Katiyar, Prvan Kumar; Misra, Sudhir; Mondal, K.

    2018-03-01

    The present work discusses the effect of pearlitic morphology on the corrosion behavior of high-carbon fully pearlitic steel in 3.5% NaCl solution. Four different types of pearlitic steels (furnace-cooled, as-received, air-cooled and forced-air-cooled) consisting of coarse, medium, fine and very fine microstructures, respectively, were tested. Electrochemical behavior of these steels was studied with the help of dynamic and linear polarization and AC impedance spectroscopic tests. The corrosion resistance improved with fineness of the microstructure in general. However, with further reduction in interlamellar spacing beyond a limit, the corrosion resistance reduced slightly. Formation of homogeneous distribution of microgalvanic cells between cementite and ferrite lamellae of fine pearlitic steel improved the corrosion resistance. However, entanglement of the lamellae of pearlite in very fine pearlitic structure as well as breaking of cementite lamellae due to finer pearlitic colonies was attributed to the higher corrosion of the forced-air-cooled steel as compared to the air-cooled steel.

  19. Electrochemical Behavior of Al-B4C Metal Matrix Composites in NaCl Solution

    PubMed Central

    Han, Yu-Mei; Chen, X.-Grant

    2015-01-01

    Aluminum based metal matrix composites (MMCs) have received considerable attention in the automotive, aerospace and nuclear industries. One of the main challenges using Al-based MMCs is the influence of the reinforcement particles on the corrosion resistance. In the present study, the corrosion behavior of Al-B4C MMCs in a 3.5 wt.% NaCl solution were investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. Results indicated that the corrosion resistance of the composites decreased when increasing the B4C volume fraction. Al-B4C composite was susceptible to pitting corrosion and two types of pits were observed on the composite surface. The corrosion mechanism of the composite in the NaCl solution was primarily controlled by oxygen diffusion in the solution. In addition, the galvanic couples that formed between Al matrix and B4C particles could also be responsible for the lower corrosion resistance of the composites. PMID:28793574

  20. Controlling the corrosion and cathodic activation of magnesium via microalloying additions of Ge

    PubMed Central

    Liu, R. L.; Hurley, M. F.; Kvryan, A.; Williams, G.; Scully, J. R.; Birbilis, N.

    2016-01-01

    The evolution of corrosion morphology and kinetics for magnesium (Mg) have been demonstrated to be influenced by cathodic activation, which implies that the rate of the cathodic partial reaction is enhanced as a result of anodic dissolution. This phenomenon was recently demonstrated to be moderated by the use of arsenic (As) alloying as a poison for the cathodic reaction, leading to significantly improved corrosion resistance. The pursuit of alternatives to toxic As is important as a means to imparting a technologically safe and effective corrosion control method for Mg (and its alloys). In this work, Mg was microalloyed with germanium (Ge), with the aim of improving corrosion resistance by retarding cathodic activation. Based on a combined analysis herein, we report that Ge is potent in supressing the cathodic hydrogen evolution reaction (reduction of water) upon Mg, improving corrosion resistance. With the addition of Ge, cathodic activation of Mg subject to cyclic polarisation was also hindered, with beneficial implications for future Mg electrodes. PMID:27350286

  1. Alloy Corrosion Considerations in Low-Cost, Clean Biomass Cookstoves for the Developing World

    DOE PAGES

    Brady, Michael P.; Banta, Kelly; Mizia, John; ...

    2017-04-01

    In nearly 40% of the world cooks on open fires or inefficient biomass-fueled cookstoves. The resulting smoke is a health hazard, contributing to an estimated 4 million premature deaths per year, as well as a major source of black carbon emissions. One solution is the introduction of improved, clean-burning biomass cookstoves. One of the most challenging components is the combustor, which must operate at high temperatures (often ≥ 600 °C) in the presence of highly corrosive species released from biomass fuel combustion, yet be sufficiently low cost to permit widespread adoption. In our present work we report the development ofmore » accelerated corrosion test screening protocols employing highly corrosive salt and water vapor species, specifically designed to evaluate alloys for clean biomass cookstove combustors, and corrosion findings for a range of commercial and developmental alloys. Lastly, a new Fe-Cr-Si base alloy that offers promise for improved corrosion resistance at lower cost than state-of the art FeCrAl and stainless steel alloys is also reported.« less

  2. Alloy Corrosion Considerations in Low-Cost, Clean Biomass Cookstoves for the Developing World

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brady, Michael P.; Banta, Kelly; Mizia, John

    In nearly 40% of the world cooks on open fires or inefficient biomass-fueled cookstoves. The resulting smoke is a health hazard, contributing to an estimated 4 million premature deaths per year, as well as a major source of black carbon emissions. One solution is the introduction of improved, clean-burning biomass cookstoves. One of the most challenging components is the combustor, which must operate at high temperatures (often ≥ 600 °C) in the presence of highly corrosive species released from biomass fuel combustion, yet be sufficiently low cost to permit widespread adoption. In our present work we report the development ofmore » accelerated corrosion test screening protocols employing highly corrosive salt and water vapor species, specifically designed to evaluate alloys for clean biomass cookstove combustors, and corrosion findings for a range of commercial and developmental alloys. Lastly, a new Fe-Cr-Si base alloy that offers promise for improved corrosion resistance at lower cost than state-of the art FeCrAl and stainless steel alloys is also reported.« less

  3. The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Sapiro, David O.

    This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron, while insulating substrates supported only localized corrosion.

  4. Corrosion Behavior and Durability of Low-Alloy Steel Rebars in Marine Environment

    NASA Astrophysics Data System (ADS)

    Liu, Ming; Cheng, Xuequn; Li, Xiaogang; Yue, Pan; Li, Jun

    2016-11-01

    The corrosion resistance of Cr-modified low-alloy steels and HRB400 carbon steel was estimated using the open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopic, and weight loss methods in simulated concrete pore solution. Results show that Cr-modified steels exhibit a higher corrosion resistance with a higher critical chloride level (CTL), lower corrosion current density, and higher impedance than carbon steel. The CTL of the steels significantly reduces with increasing temperature. Weight loss measurement shows that the Cr-modified steels exhibit low corrosion rates and small corrosion pitting. The primary constituents of the corrosion scales are Fe2O3, Fe3O4, β-FeOOH, γ-FeOOH, and α-FeOOH. A large amount of α-FeOOH could be detected in the Cr-modified steel corrosion products. Moreover, the Cr-modified steels demonstrate a higher durability than HRB400 carbon steel.

  5. The effect of heat treatment on the corrosion resistance of 440C stainless steel in 20% HNO3 + 2.5% Na2Cr2O7 solution

    NASA Astrophysics Data System (ADS)

    Savas, Terence P.; Wang, Allen Yi-Lan; Earthman, James C.

    2003-04-01

    The effect of heat treatment on the corrosion resistance of 440C stainless steel was investigated in a 20% HNO3 + 2.5% Na2Cr2O7 solution using electrochemical noise (ECN) measurements, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) examinations. The noise resistance ( Rn), which has been found to be inversely related to the localized corrosion rate, was measured to be 5.7E + 08 Ω-cm2, 4.2E + 08 Ω-cm2, and 3.7E + 04 Ω-cm2 for the oil-quenched, air-quenched, and vacuum furnace cooled (VFC) samples, respectively, after 1200 s exposures. The Rn for all heat treat conditions stabilized within a range of 1.0E + 07 Ω-cm2 to 3.2E + 08 Ω-cm2 after 2 h exposures. The EIS response showed a polarization resistance ( R p) on the order of 6.6E + 04 Ω-cm2, 5.3E + 04 Ω-cm2, and 1.1E + 04 Ω-cm2 for the oil-quenched, air-quenched, and VFC samples, respectively, after 2 h exposures. The EIS data are in good agreement with ECN data and indicate that after longer exposures, general corrosion mechanisms dominate and the corrosion rates are comparable. SEM examinations of specimens subjected to 1200 s exposures revealed that severity of pitting and intergranular corrosion damage was consistent with trends in the Rn data. Specifically, the electrochemical noise data as well as SEM examinations of specimens revealed a higher localized corrosion resistance of the hardened specimens during the early stages of passivation. This greater resistance to localized corrosion can be attributed to an increased stability of the natural passive film resulting from a higher concentration of chromium atoms in solution for the martensite phase.

  6. The effect of heat treatment simulating porcelain firing processes on titanium corrosion resistance.

    PubMed

    Sokołowski, Grzegorz; Rylska, Dorota; Sokołowski, Jerzy

    2016-01-01

    Corrosion resistance of titanium used in metal-ceramic restorations in manufacturing is based on the presence of oxide layer on the metal surface. The procedures used during combining metallic material with porcelain may affect the changes in oxide layers structure, and thus anticorrosive properties of metallic material. The aim of the study was an evaluation of potential changes in the structure and selected corrosion properties of titanium after sandblasting and thermal treatment applicable to the processes of ceramics fusion. Milled titanium elements were subjected to a few variants of the processes typical of ceramics fusion and studied in terms of resistance to electrochemical corrosion. The study included the OCP changes over time, measurements of Icorr, Ecorr and Rp as well as potentiodynamic examinations. Surface microstructure and chemical composition were analyzed using SEM and EDS methods. The results obtained allow us to conclude that the processes corresponding to ceramic oxidation and fusion on titanium in the variants used in the study do not cause deterioration of its anticorrosive properties, and partially enhance the resistance. This depends on the quality of oxide layers structure. Titanium elements treated by porcelain firing processes do not lose their corrosion resistance.

  7. Improved corrosion inspection procedures for reinforced concrete bridges : electrical resistivity of concrete.

    DOT National Transportation Integrated Search

    2015-07-01

    The effects of steel reinforcement and chloride-induced corrosion initiation on the electrical resistivity measurements using the Wenner : probe technique were studied experimentally on custom-designed reinforced concrete slabs. Investigation paramet...

  8. ZIRCONIUM ALLOY

    DOEpatents

    Wilhelm, H.A.; Ames, D.P.

    1959-02-01

    A binary zirconiuin--antimony alloy is presented which is corrosion resistant and hard containing from 0.07% to 1.6% by weight of Sb. The alloys have good corrosion resistance and are useful in building equipment for the chemical industry.

  9. 46 CFR 163.002-11 - Materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... hoist must be made of machine cut steel or machine cut bronze, or must be of a design of equivalent... hoist must be a corrosion-resistant wire rope other than galvanized wire rope. (c) Corrosion-resistant...

  10. 46 CFR 163.002-11 - Materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... hoist must be made of machine cut steel or machine cut bronze, or must be of a design of equivalent... hoist must be a corrosion-resistant wire rope other than galvanized wire rope. (c) Corrosion-resistant...

  11. Enhanced Corrosion Resistance and Interfacial Conductivity of TiC x/a-C Nanolayered Coatings via Synergy of Substrate Bias Voltage for Bipolar Plates Applications in PEMFCs.

    PubMed

    Yi, Peiyun; Zhang, Weixin; Bi, Feifei; Peng, Linfa; Lai, Xinmin

    2018-06-06

    Proton-exchange membrane fuel cells are one kind of renewable and clean energy conversion device, whose metallic bipolar plates are one of the key components. However, high interfacial contact resistance and poor corrosion resistance are still great challenges for the commercialization of metallic bipolar plates. In this study, we demonstrated a novel strategy for depositing TiC x /amorphous carbon (a-C) nanolayered coatings by synergy of 60 and 300 V bias voltage to enhance corrosion resistance and interfacial conductivity. The synergistic effects of bias voltage on the composition, microstructure, surface roughness, electrochemical corrosion behaviors, and interfacial conductivity of TiC x /a-C coatings were explored. The results revealed that the columnar structures in the inner layer were suppressed and the surface became rougher with the 300 V a-C layer outside. The composition analysis indicated that the sp 2 content increased with an increase of 300 V sputtering time. Due to the synergy strategy of bias voltage, lower corrosion current densities were achieved both in potentiostatic polarization (1.6 V vs standard hydrogen electrode) and potentiodynamic polarization. With the increase of 300 V sputtering time, the interfacial conductivity was improved. The enhanced corrosion resistance and interfacial conductivity of the TiC x /a-C coatings would provide new opportunities for commercial bipolar plates.

  12. Moessbauer spectroscopy study on the corrosion resistance of plasma nitrided ASTM F138 stainless steel in chloride solution

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Souza, S.D. de; Olzon-Dionysio, M., E-mail: dmod@df.ufscar.br; Basso, R.L.O.

    2010-10-15

    Plasma nitriding of ASTM F138 stainless steel samples has been carried out using dc glow discharge under 80% H{sub 2}-20% N{sub 2} gas mixture, at 673 K, and 2, 4, and 7 h time intervals, in order to investigate the influence of treatment time on the microstructure and the corrosion resistance properties. The samples were characterized by scanning electron microscopy, glancing angle X-ray diffraction and conversion electron Moessbauer spectroscopy, besides electrochemical tests in NaCl aerated solution. A modified layer of about 6 {mu}m was observed for all the nitrided samples, independent of nitriding time. The X-ray diffraction analysis shows broadmore » {gamma}{sub N} phase peaks, signifying a great degree of nitrogen supersaturation. Besides {gamma}{sub N,} the Moessbauer spectroscopy results indicated the occurrence of {gamma}' and {epsilon} phases, as well as some other less important phases. Corrosion measurements demonstrate that the plasma nitriding time affects the corrosion resistance and the best performance is reached at 4 h treatment. It seems that the {epsilon}/{gamma}' fraction ratio plays an important role on the resistance corrosion. Additionally, the Moessbauer spectroscopy was decisive in this study, since it was able to identify and quantify the iron phases that influence the corrosion resistance of plasma nitrided ASTM F138 samples.« less

  13. Influence of Applied Voltage and Film-Formation Time on Microstructure and Corrosion Resistance of Coatings Formed on Mg-Zn-Zr-Ca Bio-magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Yandong, Yu; Shuzhen, Kuang; Jie, Li

    2015-09-01

    The influence of applied voltage and film-formation time on the microstructure and corrosion resistance of coatings formed on a Mg-Zn-Zr-Ca novel bio-magnesium alloy has been investigated by micro-arc oxidation (MAO) treatment. Phase composition and microstructure of as-coated samples were analyzed by the x-ray diffraction, energy dispersive x-ray spectroscopy and scanning electron microscopy. And the porosity and average of micro-pore aperture of the surface on ceramic coatings were analyzed by general image software. Corrosion microstructure of as-coated samples was caught by a microscope digital camera. The long-term corrosion resistance of as-coated samples was tested in simulated body fluid for 30 days. The results showed that the milky white smooth ceramic coating formed on the Mg-Zn-Zr-Ca novel bio-magnesium alloy was a compound of MgO, Mg2SiO4 and MgSiO3, and its corrosion resistance was significantly improved compared with that of the magnesium substrate. In addition, when the MAO applied voltage were 450 V and 500 V and film-formation time were 9 min and 11 min, the surface micro-morphology and the corrosion resistance of as-coated samples were relatively improved. The results provided a theoretical foundation for the application of the Mg-Zn-Zr-Ca novel bio-magnesium alloy in biomedicine.

  14. Effect of mechanical treatment on intergranular corrosion of 6064 alloy bars

    NASA Astrophysics Data System (ADS)

    Sláma, P.; Nacházel, J.

    2017-02-01

    Aluminium Al-Mg-Si-type alloys (6xxx-series) exhibit good mechanical properties, formability, weldability and good corrosion resistance in various environments. They often find use in automotive industry and other applications. Some alloys, however, particularly those with higher copper levels, show increased susceptibility to intergranular corrosion. Intergranular corrosion (IGC) is typically related to the formation of microgalvanic cells between cathodic, more noble phases and depleted (precipitate-free) zones along grain boundaries. It is encountered mainly in AlMgSi alloys containing Cu, where it is thought to be related to the formation Q-phase precipitates (Al4Mg8Si7Cu2) along grain boundaries. The present paper describes the effects of mechanical working (extrusion, drawing and straightening) and artificial aging on intergranular corrosion in rods of the 6064 alloy. The resistance to intergranular corrosion was mapped using corrosion tests according to EN ISO 11846, method B. Corrosion tests showed dependence of corrosion type on mechanical processing of the material. Intergranular, pitting and transgranular corrosion was observed. Artificial ageing influenced mainly the depth of the corrosion.

  15. Comparative Stress Corrosion Cracking and General Corrosion Resistance of Annealed and Hardened 440 C Stainless Steel - New Techniques in Stress Corrosion Testing

    NASA Technical Reports Server (NTRS)

    Mendreck, M. J.; Hurless, B. E.; Torres, P. D.; Danford, M. D.

    1998-01-01

    The corrosion and stress corrosion cracking (SCC) characteristics of annealed and hardened 440C stainless steel were evaluated in high humidity and 3.5-percent NaCl solution. Corrosion testing consisted of an evaluation of flat plates, with and without grease, in high humidity, as well as electrochemical testing in 3.5-percent NaCl. Stress corrosion testing consisted of conventional, constant strain, smooth bar testing in high humidity in addition to two relatively new techniques under evaluation at MSFC. These techniques involve either incremental or constant rate increases in the load applied to a precracked SE(B) specimen, monitoring the crack-opening-displacement response for indications of crack growth. The electrochemical corrosion testing demonstrated an order of magnitude greater general corrosion rate in the annealed 440C. All techniques for stress corrosion testing showed substantially better SCC resistance in the annealed material. The efficacy of the new techniques for stress corrosion testing was demonstrated both by the savings in time and the ability to better quantify SCC data.

  16. Review of Thermal Spray Coating Applications in the Steel Industry: Part 2—Zinc Pot Hardware in the Continuous Galvanizing Line

    NASA Astrophysics Data System (ADS)

    Matthews, S.; James, B.

    2010-12-01

    This two-part article series reviews the application of thermal spray coating technology in the production of steel and steel sheet products. Part 2 of this article series is dedicated to coating solutions in the continuous galvanizing line. The corrosion mechanisms of Fe- and Co-based bulk materials are briefly reviewed as a basis for the development of thermal spray coating solutions. WC-Co thermal spray coatings are commonly applied to low Al-content galvanizing hardware due to their superior corrosion resistance compared to Fe and Co alloys. The effect of phase degradation, carbon content, and WC grain size are discussed. At high Al concentrations, the properties of WC-Co coatings degrade significantly, leading to the application of oxide-based coatings and corrosion-resistant boride containing coatings. The latest results of testing are summarized, highlighting the critical coating parameters.

  17. Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

    NASA Astrophysics Data System (ADS)

    Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.

    2017-06-01

    An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

  18. Corrosion-resistant catalyst supports for phosphoric acid fuel cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kosek, J.A.; Cropley, C.C.; LaConti, A.B.

    High-surface-area carbon blacks such as Vulcan XC-72 (Cabot Corp.) and graphitized carbon blacks such as 2700{degree}C heat-treated Black Pearls 2000 (HTBP) (Cabot Corp.) have found widespread applications as catalyst supports in phosphoric acid fuel cells (PAFCs). However, due to the operating temperatures and pressures being utilized in PAFCs currently under development, the carbon-based cathode catalyst supports suffer from corrosion, which decreases the performance and life span of a PAFC stack. The feasibility of using alternative, low-cost, corrosion-resistant catalyst support (CRCS) materials as replacements for the cathode carbon support materials was investigated. The objectives of the program were to prepare high-surface-areamore » alternative supports and to evaluate the physical characteristics and the electrochemical stability of these materials. The O{sub 2} reduction activity of the platinized CRCS materials was also evaluated. 2 refs., 3 figs.« less

  19. Electrochemical Testing of Ni-Cr-Mo-Gd Alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    T. E. Lister; R. E. Mizia; H. Tian

    2005-10-01

    The waste package site recommendation design specified a boron-containing stainless steel, Neutronit 976/978, for fabrication of the internal baskets that will be used as a corrosion-resistant neutron-absorbing material. Recent corrosion test results gave higher-than-expected corrosion rates for this material. The material callout for these components has been changed to a Ni-Cr-Mo-Gd alloy (ASTM-B 932-04, UNS N06464) that is being developed at the Idaho National Laboratory. This report discusses the results of initial corrosion testing of this material in simulated in-package environments that could contact the fuel baskets after breach of the waste package outer barrier. The corrosion test matrix wasmore » executed using the potentiodynamic and potentiostatic electrochemical test techniques. The alloy performance shows low rates of general corrosion after initial removal of a gadolinium-rich second phase that intersects the surface. The high halide-containing test solutions exhibited greater tendencies toward initiation of crevice corrosion.« less

  20. 46 CFR 129.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Protection from wet and corrosive environments. 129.210... ELECTRICAL INSTALLATIONS General Requirements § 129.210 Protection from wet and corrosive environments. (a... exposed to corrosive environments must be of suitable construction and must be resistant to corrosion. ...

  1. 46 CFR 129.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Protection from wet and corrosive environments. 129.210... ELECTRICAL INSTALLATIONS General Requirements § 129.210 Protection from wet and corrosive environments. (a... exposed to corrosive environments must be of suitable construction and must be resistant to corrosion. ...

  2. 46 CFR 129.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Protection from wet and corrosive environments. 129.210... ELECTRICAL INSTALLATIONS General Requirements § 129.210 Protection from wet and corrosive environments. (a... exposed to corrosive environments must be of suitable construction and must be resistant to corrosion. ...

  3. 46 CFR 129.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Protection from wet and corrosive environments. 129.210... ELECTRICAL INSTALLATIONS General Requirements § 129.210 Protection from wet and corrosive environments. (a... exposed to corrosive environments must be of suitable construction and must be resistant to corrosion. ...

  4. 46 CFR 129.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 129.210... ELECTRICAL INSTALLATIONS General Requirements § 129.210 Protection from wet and corrosive environments. (a... exposed to corrosive environments must be of suitable construction and must be resistant to corrosion. ...

  5. 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.

  6. Microhardness and In Vitro Corrosion of Heat-Treated Mg–Y–Ag Biodegradable Alloy

    PubMed Central

    Vlček, Marián; Lukáč, František; Kudrnová, Hana; Smola, Bohumil; Stulíková, Ivana; Luczak, Monika; Szakács, Gábor; Hort, Norbert; Willumeit-Römer, Regine

    2017-01-01

    Magnesium alloys are promising candidates for biodegradable medical implants which reduce the necessity of second surgery to remove the implants. Yttrium in solid solution is an attractive alloying element because it improves mechanical properties and exhibits suitable corrosion properties. Silver was shown to have an antibacterial effect and can also enhance the mechanical properties of magnesium alloys. Measurements of microhardness and electrical resistivity were used to study the response of Mg–4Y and Mg–4Y–1Ag alloys to isochronal or isothermal heat treatments. Hardening response and electrical resistivity annealing curves in these alloys were compared in order to investigate the effect of silver addition. Procedures for solid solution annealing and artificial aging of the Mg–4Y–1Ag alloy were developed. The corrosion rate of the as-cast and heat-treated Mg–4Y–1Ag alloy was measured by the mass loss method. It was found out that solid solution heat treatment, as well artificial aging to peak hardness, lead to substantial improvement in the corrosion properties of the Mg–4Y–1Ag alloy. PMID:28772414

  7. Surface properties of AZ91 magnesium alloy after PEO treatment using molybdate salts and low current densities

    NASA Astrophysics Data System (ADS)

    Pezzato, Luca; Brunelli, Katya; Napolitani, Enrico; Magrini, Maurizio; Dabalà, Manuele

    2015-12-01

    Plasma electrolytic oxidation (PEO) process is a recently developed electrochemical method used to produce on the surface of various metals oxide ceramic coatings that improve corrosion and wear properties of the substrate. In this work, PEO process was applied on AZ91 magnesium alloy using low current densities (0.05 A/cm2) and an alkaline solution of silicates with different concentrations of sodium molybdate (0.3-3 g/l). The effect of the low current densities of process and of molybdate salts on the corrosion resistance of the coatings was studied with potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) in chloride and sulfate environment. The morphology, the phases and the chemical composition of the coatings were examined using a scanning electron microscope equipped with EDS, X-ray diffraction, secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The corrosion properties of the PEO coated samples were remarkably improved if compared with the uncoated samples. The addition of sodium molybdate, in determinate conditions, had a positive effect on the characteristics of the coatings in terms of corrosion resistance.

  8. Development of Electrodeposited Zn/nano-TiO2 Composite Coatings with Enhanced Corrosion Performance

    NASA Astrophysics Data System (ADS)

    Benea, L.; Dănăilă, E.

    2017-06-01

    Pure zinc coatings have been found ineffective when are used in aggressive environments such as those which contain chlorides or industrial pollutants [1]. In this paper, Zn/nano-TiO2 composite coatings with various contents of TiO2 nanoparticles (diameter size of 10 nm) were prepared on low-carbon steel by electro-codeposition technique. The deposition was carried out at different cathodic potentials ranging from -1600 mV to -2100 mV for different deposition times between 5-15 min. Pure Zn coatings were also produced under the same experimental conditions for comparison. Present work aims to investigate the effects of selected electrodeposition parameters (cathodic potential, TiO2 nanoparticle concentration in the plating bath and electrodeposition time) on the corrosion behavior of electrodeposited Zn/nano-TiO2 composite obtained. The corrosion experiments were performed in natural seawater, using electrochemical methods such as open circuit potential, potentiodynamic polarization and linear polarization resistance. The results showed that the inclusion of TiO2 nanoparticles into zinc matrix lead to an improved corrosion resistance comparatively with pure zinc coatings obtained under similar conditions.

  9. "Electroless" E-Coating for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Song, Guang-Ling

    By utilizing the unique electrochemistry of Mg, a thin organic film can rapidly be deposited on the surface of a Mg alloy by dipping the Mg alloy in a cathodic E-coating bath solution without applying a current or potential. The self-deposited coating is selectively formed on Mg alloy surfaces. Although the "electroless" E-coating pre-film is relatively thin, it can offer sufficient corrosion protection for Mg alloys in a chloride-containing environment. The stability of the film can be significantly improved after curing. The corrosion resistance of the substrate Mg alloy has an important effect on the corrosion protection performance of the coating. The coating is more protective on a corrosion resistant Mg alloy than on a non-corrosion resistant Mg substrate. The coating protection performance is also influenced by the substrate surface condition or pre-treatment process. Wet cleaning + heat-treatment may be a cost-effective surface preparation/treatment for the "electroless" E-coating in industrial applications.

  10. In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films

    PubMed Central

    Wu, Junsheng; Peng, Dongdong; He, Yuntao; Du, Xiaoqiong; Zhang, Zhan; Zhang, Bowei; Li, Xiaogang; Huang, Yizhong

    2017-01-01

    A layered double hydroxide (LDH) film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V) film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM). The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS), scanning electrochemical microscopy (SECM), and a salt-spray test (SST).The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film. PMID:28772785

  11. Improvement of Adhesion Properties and Corrosion Resistance of Sol-Gel Coating on Zinc.

    PubMed

    Savignac, Pauline; Menu, Marie-Joëlle; Gressier, Marie; Denat, Bastien; Khadir, Yacine El; Manov, Stephan; Ansart, Florence

    2018-05-03

    Corrosion is a major problem for durability of many metals and alloys. Among the efficient classical surface treatments, chromate-based treatments must be banished from industrial use due to their toxicity. At the same time, sol-gel routes have demonstrated high potential to develop an efficient barrier effect against aggressive environments. By this process, the anti-corrosion property can be also associated to others in the case of the development of multi-functional hybrid coatings. In this paper, the main goal is precisely to improve both the corrosion resistance and the adhesion properties of phosphated zinc substrates by the deposition of a hybrid (organic-inorganic) sol-gel layer. To reach this double objective, a choice between two formulations 3-glycidoxypropyltrimethoxysilane (GPTMS)/aluminum-tri-sec-butoxide (ASB) and 3-(trimethoxysilyl)propylmethacrylate (MAP)/tetraethylorthosilicate (TEOS) was firstly made based on the results obtained by microstructural characterizations using SEM, optical analysis, and mechanical characterization such as shock and/or scratch tests (coupled to climatic chamber and salt spray exposure). Several investigations were performed in this study, and the best formulation and performances of the system were obtained by adding a new precursor (1-[3-(trimethoxysilyl)propyl]ureido-UPS) under controlled conditions, as detailed in this paper.

  12. Gas-deposit-alloy corrosion interactions in simulated combustion environments

    NASA Astrophysics Data System (ADS)

    Luer, Kevin Raymond

    High temperature corrosion in aggressive coal combustion environments involves simultaneous corrosion reactions between combustion gases, ash deposits, and alloys. This research investigated the behavior of a ferritic steel (SA387-Gr11) and three weld claddings (309L SS, Alloy 72, and Alloy 622) in five combustion environments beneath solid deposits at 500°C for up to 1000 hours. The synthetic gases consisted of N2-CO-CO-H2-H2O-H 2S-SO2 mixtures that simulated a range of fuel-rich or fuel-lean combustion environments with a constant sulfur content. The synthetic deposits contained FeS2, FeS, Fe3O4 and/or carbon. Reaction kinetics was studied in individual gas-metal, gas deposit, and deposit-alloy systems. A test method was developed to investigate simultaneous gas-deposit-metal corrosion reactions. The results showed reaction kinetics varied widely, depending on the gas-alloy system and followed linear, parabolic, and logarithmic rate laws. Under reducing conditions, the alloys exhibited a range of corrosion mechanisms including carburization-sulfidation, sulfidation, and sulfidation-oxidation. Most alloys were not resistant to the highly reducing gases but offered moderate resistance to mixed oxidation-sulfidation by demonstrating parabolic or logarithmic behavior. Under oxidizing conditions, all of the alloys were resistant. Under oxidizing-sulfating conditions, alloys with high Fe or Cr contents sulfated whereas an alloy containing Mo and W was resistant. In the gas-deposit-metal tests, FeS2-bearing deposits were extremely corrosive to low alloy steel under both reducing and oxidizing conditions but they had little influence on the weld claddings. Accelerated corrosion was attributed to rapid decomposition or oxidation of FeS2 particles that generated sulfur-rich gases above the alloy surface. In contrast, FeS-type deposits had no influence under reducing conditions but they were aggressive to low alloy steel under oxidizing conditions. The extent of damage correlated with the initial sulfur content in the deposit. Fe3O4 in the deposit was beneficial because it acted as a sulfur getter or oxygen source. Carbon had a mixed effect. The reaction behavior was modeled using computational thermochemistry based on Gibbs free energy minimization. A calculation method was introduced to predict equilibrium corrosion microstructures and trace reaction paths in complex gas-deposit-metal environments. Kinetic factors were identified where equilibrium reaction products were not experimentally observed.

  13. Effect of Waterproofing Admixtures on the Flexural Strength and Corrosion Resistance of Concrete

    NASA Astrophysics Data System (ADS)

    Geetha, A.; Perumal, P.

    2012-02-01

    This paper deals about the flexural strength and corrosion behaviour of concrete using waterproofing admixtures. The effect of waterproofing admixtures on the corrosion behaviour of RCC specimen has been studied by conducting accelerated corrosion test. To identify the effect of corrosion in pull out strength, corrosion process was induced by means of accelerated corrosion procedure. To accelerate the reinforcement corrosion, direct electric current was impressed on the rebar embedded in the specimen using a DC power supply system that has a facility to adjust voltage. The addition of waterproofing admixtures also shows the improvement in the flexural strength of concrete has been studied by conducting flexural strength tests on the concrete prism specimen of size 100 × 100 × 500 mm with and without admixtures for various dosages and various curing periods of 7 and 28 days. The results showed that the presence of waterproofing admixtures always improves the corrosion resistance and thus increases the strength of concrete due to the hydrophobic action of waterproofing admixtures.

  14. Environmental protection of titanium alloys at high temperatures

    NASA Technical Reports Server (NTRS)

    Wright, I. G.; Wood, R. A.; Seltzer, M. S.

    1974-01-01

    Various concepts were evaluated for protecting titanium alloys from oxygen contamination at 922 K (1200 F) and from hot-salt stress-corrosion at 755 K (900 F). It is indicated that oxygen-contamination resistance can be provided by a number of systems, but for hot-salt stress-corrosion resistance, factors such as coating integrity become very important. Titanium aluminides resist oxygen ingress at 922 K through the formation of alumina (on TiAl3) or modified TiO2 (on Ti3Al, TiAl) scales. TiAl has some resistance to attack by hot salt, but has limited ductility. Ductile Ti-Ni and Ti-Nb-Cr-Al alloys provide limited resistance to oxygen ingress, but are not greatly susceptible to hot-salt stress-corrosion cracking.

  15. 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.

  16. 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.

  17. Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farmer, J C

    2003-04-15

    DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption inmore » crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with temperature controlled cells for potentiostatic and potentiodynamic testing (Figure 2).« less

  18. White primer permits a corrosion-resistant coating of minimum weight

    NASA Technical Reports Server (NTRS)

    Albrecht, R. H.; Jensen, D. P.; Schnake, P.

    1966-01-01

    White primer for coating 2219 aluminum alloy supplies a base for a top coating of enamel. A formulation of pigments and vehicle results in a primer with high corrosion resistance and minimum film thickness.

  19. Influence of Hydrostatic Pressure on the Corrosion Behavior of Superhydrophobic Surfaces on Bare and Oxidized Aluminum Substrates.

    PubMed

    Ou, J F; Fang, X Z; Zhao, W J; Lei, S; Xue, M S; Wang, F J; Li, C Q; Lu, Y L; Li, W

    2018-05-22

    It is generally recognized that superhydrophobic surfaces in water may be used for corrosion resistance due to the entrapped air in the solid/liquid interface and could find potential applications in the protection of ship hull. For a superhydrophobic surface, as its immersion depth into water increases, the resultant hydrostatic pressure is also increased, and the entrapped air can be squeezed out much more easily. It is therefore predicted that high hydrostatic pressure would cause an unexpected decrease in corrosion resistance for the vessels in deep water (e.g., submarines) because of the unstable entrapped air. In this work, in order to clarify the role of hydrostatic pressure in the corrosion behavior of superhydrophobic surfaces, two typical superhydrophobic surfaces (SHSs) were prepared on bare and oxidized aluminum substrates, respectively, and then were immersed into the NaCl aqueous solutions with different depths of ∼0 cm (hydrostatic pressure ∼0 kPa), 10 cm (1 kPa), and 150 cm (15 kPa). It was found out for the SHSs on the oxidized Al, as the hydrostatic pressure increased, the corrosion behavior became severe. However, for the SHSs on the bare Al, their corrosion behavior was complex due to hydrostatic pressure. It was found that the corrosion resistance under 1 kPa was the highest. Further mechanism analysis revealed that this alleviated corrosion behavior under 1 kPa resulted from suppressing the oxygen diffusion through the liquid and reducing the subsequent corrosion rate as compared with 0 kPa, whereas the relatively low hydrostatic pressure (HP) could stabilize the entrapped air and hence enhance the corrosion resistance, compared with 15 kPa. The present study therefore provided a fundamental understanding for the applications of SHSs to prevent the corrosion, especially for various vessels in deep water.

  20. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    NASA Astrophysics Data System (ADS)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  1. Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel

    PubMed Central

    Song, Sol-Ji; Kim, Jung-Gu

    2018-01-01

    This study examined the synergic effect of alloying the element Cr and the environmental element Mg2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) tests and weight-loss tests. The Mg2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe2O4 and a mixed layer (Cr oxide + FeCr2O4 + MgCr2O4) improved the corrosion resistance of the low-alloy steel in the seawater. PMID:29361710

  2. Improving the corrosion resistance of Mg-4.0Zn-0.2Ca alloy by micro-arc oxidation.

    PubMed

    Xia, Y H; Zhang, B P; Lu, C X; Geng, L

    2013-12-01

    In this paper, corrosion resistance of the Mg-4.0Zn-0.2Ca alloy was modified by micro-arc oxidation (MAO) process. The microstructure and phase constituents of MAO layer were characterized by SEM, XRD and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of MAO treated Mg-4.0Zn-0.2Ca alloy in the simulated body fluid were characterized by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The microstructure results indicated that a kind of ceramic film was composed by MgO and MgF2 was formed on the surface of Mg-4.0Zn-0.2Ca alloy after MAO treatment. The electrochemical test reveals that the corrosion resistance of MAO treated samples increase 1 order of magnitude. The mechanical intensity test showed that the MAO treated samples has suitable mechanical properties. © 2013.

  3. Microstructure, phase composition and corrosion resistance of Ni2O3 coatings produced using laser alloying method

    NASA Astrophysics Data System (ADS)

    Bartkowska, Aneta; Przestacki, Damian; Chwalczuk, Tadeusz

    2016-12-01

    The paper presents the studies' results of microstructure, microhardness, cohesion, phase composition and the corrosion resistance analysis of C45 steel after laser alloying with nickel oxide (Ni2O3). The aim of the laser alloying was to obtain the surface layer with new properties through covering C45 steel by precoat containing modifying compound, and then remelting this precoat using laser beam. As a result of this process the surface layer consisting of remelted zone and heat affected zone was obtained. In the remelted zone an increased amount of modifying elements was observed. It was also found that the surface layer formed during the laser alloying with Ni2O3 was characterized by good corrosion resistance. This property has changed depending on the thickness of the applied precoat. It was observed that the thickness increase of nickel oxides precoat improves corrosion resistance of produced coatings.

  4. Microstructure, Mechanical Properties, and Corrosion Resistance of Thermomechanically Processed AlZn6Mg0.8Zr Alloy

    PubMed Central

    Kowalski, Aleksander; Ozgowicz, Wojciech; Jurczak, Wojciech; Grajcar, Adam; Boczkal, Sonia; Żelechowski, Janusz

    2018-01-01

    The paper presents results of the investigations on the effect of low-temperature thermomechanical treatment (LTTT) on the microstructure of AlZn6Mg0.8Zr alloy (7000 series) and its mechanical properties as well as electrochemical and stress corrosion resistance. For comparison of the LTTT effect, the alloy was subjected to conventional precipitation hardening. Comparative studies were conducted in the fields of metallographic examinations and static tensile tests. It was found that mechanical properties after the LTTT were better in comparison to after conventional heat treatment (CHT). The tested alloy after low-temperature thermomechanical treatment with increasing plastic deformation shows decreased electrochemical corrosion resistance during potentiodynamic tests. The alloy after low-temperature thermomechanical treatment with deformation degree in the range of 10 to 30% is characterized by a high resistance to stress corrosion specified by the level of PSCC indices. PMID:29642448

  5. Microstructure Characterization and Corrosion Resistance Behavior of New Cobalt-Free Maraging Steel Produced Through ESR Techniques

    NASA Astrophysics Data System (ADS)

    Seikh, Asiful H.; Halfa, Hossam; Baig, Muneer; Khan, Sohail M. A.

    2017-04-01

    In this study, two different grades (M23 and M29) of cobalt-free low nickel maraging steel have been produced through electroslag remelting (ESR) process. The corrosion resistance of these ESR steels was investigated in 1 M H2SO4 solution using linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) techniques. The experiments were performed for different immersion time and solution temperature. To evaluate the corrosion resistance of the ESR steels, some significant characterization parameters from LPP and EIS curves were analyzed and compared with that of conventional C250 maraging steel. Irrespective of measurement techniques used, the results show that the corrosion resistance of the ESR steels was higher than the C250 steel. The microstructure of ESR steels was composed of uniform and well-distributed martensite accompanied with little amount of retained austenite in comparison with C250 steel.

  6. Influence of silica nanospheres on corrosion behavior of magnesium matrix syntactic foam

    NASA Astrophysics Data System (ADS)

    Qureshi, W.; Kannan, S.; Vincent, S.; Eddine, N. N.; Muhammed, A.; Gupta, M.; Karthikeyan, R.; Badari, V.

    2018-04-01

    Over the years, the development of Magnesium alloys as biodegradable implants has seen significant advancements. Magnesium based materials tend to provide numerous advantages in the field of biomedical implants over existing materials such as titanium or stainless steel. The present research focuses on corrosive behavior of Magnesium reinforced with different volume percentages of Hollow Silica Nano Spheres (HSNS). These behaviors were tested in two different simulated body fluids (SBF) namely, Hank’s Buffered Saline Solution (HBSS) and Phosphate Buffered Solution (PBS). This corrosion study was done using the method of electrochemical polarization with a three-electrode configuration. Comparative studies were established by testing pure Mg which provided critical information on the effects of the reinforcing material. The HSNS reinforced Mg displayed desirable characteristics after corrosion experiments; increased corrosion resistance was witnessed with higher volume percentage of HSNS.

  7. Passivation Characteristics of Alloy Corrosion-Resistant Steel Cr10Mo1 in Simulating Concrete Pore Solutions: Combination Effects of pH and Chloride

    PubMed Central

    Ai, Zhiyong; Sun, Wei; Jiang, Jinyang; Song, Dan; Ma, Han; Zhang, Jianchun; Wang, Danqian

    2016-01-01

    The electrochemical behaviour for passivation of new alloy corrosion-resistant steel Cr10Mo1 immersed in alkaline solutions with different pH values (13.3, 12.0, 10.5, and 9.0) and chloride contents (0.2 M and 1.0 M), was investigated by various electrochemical techniques: linear polarization resistance, electrochemical impedance spectroscopy and capacitance measurements. The chemical composition and structure of passive films were determined by XPS. The morphological features and surface composition of the immersed steel were evaluated by SEM together with EDS chemical analysis. The results evidence that pH plays an important role in the passivation of the corrosion-resistant steel and the effect is highly dependent upon the chloride contents. In solutions with low chloride (0.2 M), the corrosion-resistant steel has notably enhanced passivity with pH falling from 13.3 to 9.0, but does conversely when in presence of high chloride (1.0 M). The passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer enriched in Fe oxides and hydroxides, and an inner layer, rich in Cr species. The film composition varies with pH values and chloride contents. As the pH drops, more Cr oxides are enriched in the film while Fe oxides gradually decompose. Increasing chloride promotes Cr oxides and Fe oxides to transform into their hydroxides with little protection, and this is more significant at lower pH (10.5 and 9.0). These changes annotate passivation characteristics of the corrosion-resistant steel in the solutions of different electrolyte. PMID:28773867

  8. Passivation Characteristics of Alloy Corrosion-Resistant Steel Cr10Mo1 in Simulating Concrete Pore Solutions: Combination Effects of pH and Chloride.

    PubMed

    Ai, Zhiyong; Sun, Wei; Jiang, Jinyang; Song, Dan; Ma, Han; Zhang, Jianchun; Wang, Danqian

    2016-09-01

    The electrochemical behaviour for passivation of new alloy corrosion-resistant steel Cr10Mo1 immersed in alkaline solutions with different pH values (13.3, 12.0, 10.5, and 9.0) and chloride contents (0.2 M and 1.0 M), was investigated by various electrochemical techniques: linear polarization resistance, electrochemical impedance spectroscopy and capacitance measurements. The chemical composition and structure of passive films were determined by XPS. The morphological features and surface composition of the immersed steel were evaluated by SEM together with EDS chemical analysis. The results evidence that pH plays an important role in the passivation of the corrosion-resistant steel and the effect is highly dependent upon the chloride contents. In solutions with low chloride (0.2 M), the corrosion-resistant steel has notably enhanced passivity with pH falling from 13.3 to 9.0, but does conversely when in presence of high chloride (1.0 M). The passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer enriched in Fe oxides and hydroxides, and an inner layer, rich in Cr species. The film composition varies with pH values and chloride contents. As the pH drops, more Cr oxides are enriched in the film while Fe oxides gradually decompose. Increasing chloride promotes Cr oxides and Fe oxides to transform into their hydroxides with little protection, and this is more significant at lower pH (10.5 and 9.0). These changes annotate passivation characteristics of the corrosion-resistant steel in the solutions of different electrolyte.

  9. Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

  10. Long-term high-velocity oxidation and hot corrosion testing of several NiCrAl and FeCrAl base oxide dispersion strengthened alloys

    NASA Technical Reports Server (NTRS)

    Lowell, C. E.; Deadmore, D. L.; Whittenberger, J. D.

    1982-01-01

    Several oxide dispersion strengthened (ODS) alloys have been tested for cyclic, long-term, high gas-velocity resistance to oxidation at 1100 C and hot corrosion at 900 C. Both nominally Ni-16Cr-4Al and Fe-20Cr-4.5Al ODS alloys were subjected up to about 2500 cycles, where each cycle consisted of 1 hr in a hot, Mach 0.3 combusted gas stream followed by a 3-min quench in an ambient temperature, Mach 0.3 air blast. For comparison to existing technology, a coated superalloy was simultaneously tested. The ODS iron alloy exhibited clearly superior behavior, surviving 3800 oxidation and 2300 hot corrosion cycles essentially unscathed. While the ODS nickel alloys exhibited adequate oxidation resistance, the long-term hot corrosion resistance could be marginal, since the best life for such alloys under these conditions was only about 1100 cycles. However, the hot corrosion resistance of the ODS Ni-base alloys is excellent in comparison to that of traditional superalloys.

  11. Improving the Corrosion Resistance of Biodegradable Magnesium Alloys by Diffusion Coating Process

    NASA Astrophysics Data System (ADS)

    Levy, Galit Katarivas; Aghion, Eli

    Magnesium alloys suffer from accelerated corrosion in physiological environment and hence their use as a structural material for biodegradable implants is limited. The present study focuses on a diffusion coating treatment that amplifies the beneficial effect of Neodymium on the corrosion resistance of magnesium alloys. The diffusion coating layer was obtained by applying 1 µm Nd coating on EW10X04 magnesium alloy using Electron-gun evaporator and PVD process. The coated alloy was heat treated at 350°C for 3 hours in a protective atmosphere of N2+0.2%SF6. The micro structure characteristics were evaluated by SEM, XRD, and XPS; the corrosion resistance was examined by potentiodynamic polarization and EIS analysis. The corrosion resistance of the diffusion coated alloy was significantly improved compared to the uncoated material. This was related to: (i) formation of Nd2O3 in the outer scale, (ii) integration of Nd in the MgO oxide layer, and (iii) formation of secondary phase Mg41Nd5 along the grain boundaries of α-Mg.

  12. Corrosion resistance of BIS 2062-grade steel coated with nano-metal-oxide mixtures of iron, cerium, and titanium in the marine environment

    NASA Astrophysics Data System (ADS)

    Ashraf, P. Muhamed; Anuradha, R.

    2018-02-01

    BIS 2062-grade carbon steel is extensively used for fishing boat construction. The steel is highly susceptible to corrosion on the hull and welding joints under marine environment. Here, we demonstrate the application of a novel multifunctional nano-metal-oxide mixture comprised of iron, titanium, and cerium as a marine coating to prevent corrosion. The electrochemical performance of nano-metal-oxide mixture coatings, applied over boat-building steel, was evaluated at 3.5% NaCl medium. The nano-mixture surface coatings showed an efficient corrosion resistance with increased polarization resistance of 6043 Ω cm2 and low corrosion current density of 3.53 × 10-6 A cm-2. The electrochemical impedance spectral data exhibited improvement in the polarization resistance of outermost surface and internal layers. The coating responded faster recovery to normal state when subjected to an induced stress over the coating. The nano-material in the coating behaves as a semiconductor; this enhanced electronic activity over the surface of the steel.

  13. High-Performance Polyimide Powder Coatings

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Much of the infrastructure at Kennedy Space Center and other NASA sites has been subjected to outside weathering effects for more than 40 years. Because much of this infrastructure has metallic surfaces, considerable effort is continually devoted to developing methods to minimize the effects of corrosion on these surfaces. These efforts are especially intense at KSC, where offshore salt spray and exhaust from Solid Rocket Boosters accelerate corrosion. Coatings of various types have traditionally been the choice for minimizing corrosion, and improved corrosion control methods are constantly being researched. Recent work at KSC on developing an improved method for repairing Kapton (polyimide)-based electrical wire insulation has identified polyimides with much lower melting points than traditional polyimides used for insulation. These lower melting points and the many other outstanding physical properties of polyimides (thermal stability, chemical resistance, and electrical properties) led us to investigate whether they could be used in powder coatings.

  14. Electrochemical Behavior of Sn-9Zn-xTi Lead-Free Solders in Neutral 0.5M NaCl Solution

    NASA Astrophysics Data System (ADS)

    Wang, Zhenghong; Chen, Chuantong; Jiu, Jinting; Nagao, Shijo; Nogi, Masaya; Koga, Hirotaka; Zhang, Hao; Zhang, Gong; Suganuma, Katsuaki

    2018-03-01

    Electrochemical techniques were employed to study the electrochemical corrosion behavior of Sn-9Zn-xTi (x = 0, 0.05, 0.1, 0.2 wt.%) lead-free solders in neutral 0.5M NaCl solution, aiming to figure out the effect of Ti content on the corrosion properties of Sn-9Zn, providing information for the composition design of Sn-Zn-based lead-free solders from the perspective of corrosion. EIS results reveal that Ti addition was involved in the corrosion product layer and changed electrochemical interface behavior from charge transfer control process to diffusion control process. The trace amount of Ti addition (0.05 wt.%) can refine the microstructure and improve the corrosion resistance of Sn-9Zn solder, evidenced by much lower corrosion current density (i corr) and much higher total resistance (R t). Excess Ti addition (over 0.1 wt.%) led to the formation of Ti-containing IMCs, which were confirmed as Sn3Ti2 and Sn5Ti6, deteriorating the corrosion resistance of Sn-9Zn-xTi solders. The main corrosion products were confirmed as Sn3O(OH)2Cl2 mixed with small amount of chlorine/oxide Sn compounds.

  15. Electrochemical Behavior of Sn-9Zn- xTi Lead-Free Solders in Neutral 0.5M NaCl Solution

    NASA Astrophysics Data System (ADS)

    Wang, Zhenghong; Chen, Chuantong; Jiu, Jinting; Nagao, Shijo; Nogi, Masaya; Koga, Hirotaka; Zhang, Hao; Zhang, Gong; Suganuma, Katsuaki

    2018-05-01

    Electrochemical techniques were employed to study the electrochemical corrosion behavior of Sn-9Zn- xTi ( x = 0, 0.05, 0.1, 0.2 wt.%) lead-free solders in neutral 0.5M NaCl solution, aiming to figure out the effect of Ti content on the corrosion properties of Sn-9Zn, providing information for the composition design of Sn-Zn-based lead-free solders from the perspective of corrosion. EIS results reveal that Ti addition was involved in the corrosion product layer and changed electrochemical interface behavior from charge transfer control process to diffusion control process. The trace amount of Ti addition (0.05 wt.%) can refine the microstructure and improve the corrosion resistance of Sn-9Zn solder, evidenced by much lower corrosion current density ( i corr) and much higher total resistance ( R t). Excess Ti addition (over 0.1 wt.%) led to the formation of Ti-containing IMCs, which were confirmed as Sn3Ti2 and Sn5Ti6, deteriorating the corrosion resistance of Sn-9Zn- xTi solders. The main corrosion products were confirmed as Sn3O(OH)2Cl2 mixed with small amount of chlorine/oxide Sn compounds.

  16. Comparative microstructural and corrosion development of VCrNiCoFeCu equiatomic multicomponent alloy produced by induction melting and spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Fazakas, É.; Heczel, A.; Molnár, D.; Varga, B.; Zadorozhnyy, V.; Vida, Á.

    2018-03-01

    The present study focuses on the corrosion behavior of a single-phase FCC high entropy alloy (VCrNiCoFeCu) casted by two different methods: induction melting and spark plasma sintering. The corrosion resistance has been evaluated using immersion tests in 3.5% NaCl solution, the potentiodynamic polarization measurements and the results are compared how is dependent the corrosion rate as a function of the production methods. Our results show that induction melted sample is stable in salty environment. On the other hand, based on the changes of polarization curves, there must be an evolution of oxide films on the SPSed sample until reaching the stable oxide layer.

  17. Experiments and models of general corrosion and flow-assisted corrosion of materials in nuclear reactor environments

    NASA Astrophysics Data System (ADS)

    Cook, William Gordon

    Corrosion and material degradation issues are of concern to all industries. However, the nuclear power industry must conform to more stringent construction, fabrication and operational guidelines due to the perceived additional risk of operating with radioactive components. Thus corrosion and material integrity are of considerable concern for the operators of nuclear power plants and the bodies that govern their operations. In order to keep corrosion low and maintain adequate material integrity, knowledge of the processes that govern the material's breakdown and failure in a given environment are essential. The work presented here details the current understanding of the general corrosion of stainless steel and carbon steel in nuclear reactor primary heat transport systems (PHTS) and examines the mechanisms and possible mitigation techniques for flow-assisted corrosion (FAC) in CANDU outlet feeder pipes. Mechanistic models have been developed based on first principles and a 'solution-pores' mechanism of metal corrosion. The models predict corrosion rates and material transport in the PHTS of a pressurized water reactor (PWR) and the influence of electrochemistry on the corrosion and flow-assisted corrosion of carbon steel in the CANDU outlet feeders. In-situ probes, based on an electrical resistance technique, were developed to measure the real-time corrosion rate of reactor materials in high-temperature water. The probes were used to evaluate the effects of coolant pH and flow on FAC of carbon steel as well as demonstrate of the use of titanium dioxide as a coolant additive to mitigated FAC in CANDU outlet feeder pipes.

  18. A high-strength silicide phase in a stainless steel alloy designed for wear-resistant applications.

    PubMed

    Bowden, D; Krysiak, Y; Palatinus, L; Tsivoulas, D; Plana-Ruiz, S; Sarakinou, E; Kolb, U; Stewart, D; Preuss, M

    2018-04-10

    Hardfacing alloys provide strong, wear-resistant and corrosion-resistant coatings for extreme environments such as those within nuclear reactors. Here, we report an ultra-high-strength Fe-Cr-Ni silicide phase, named π-ferrosilicide, within a hardfacing Fe-based alloy. Electron diffraction tomography has allowed the determination of the atomic structure of this phase. Nanohardness testing indicates that the π-ferrosilicide phase is up to 2.5 times harder than the surrounding austenite and ferrite phases. The compressive strength of the π-ferrosilicide phase is exceptionally high and does not yield despite loading in excess of 1.6 GPa. Such a high-strength silicide phase could not only provide a new type of strong, wear-resistant and corrosion-resistant Fe-based coating, replacing more costly and hazardous Co-based alloys for nuclear applications, but also lead to the development of a new class of high-performance silicide-strengthened stainless steels, no longer reliant on carbon for strengthening.

  19. Effects of pH Value of the Electrolyte and Glycine Additive on Formation and Properties of Electrodeposited Zn-Fe Coatings

    PubMed Central

    2013-01-01

    Environmentally friendly and cyanide-free sulfate bath under continuous current and the corrosion behavior of electrodeposits of zinc-iron alloys were studied by means of electrochemical tests in a solution of 3.5% NaCl in presence and absence of glycine. The effects of pH on the quality of Zn-Fe coatings were investigated in order to improve uniformity and corrosion protection performance of the coating films. The deposit morphology was analyzed using scanning electron microscopy (SEM), and X-ray diffraction (XRD) was used to determine the preferred crystallographic orientations of the deposits. It was found that the uniformity and corrosion resistance of Zn-Fe coating films were strongly associated with pH of the coating electrolyte. To obtain the effect of pH on the film quality and corrosion performances of the films, the corrosion test was performed with potentiodynamic anodic polarization method. It was also observed that uniformity and corrosion resistivity of the coating films were decreased towards pH = 5 and then improved with increasing pH value of the electrolyte. The presence of glycine in the plating bath decreases the corrosion resistance of Zn-Fe coatings. PMID:23844388

  20. Chromium modified nickel-iron aluminide useful in sulfur bearing environments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cathcart, J.V.; Liu, C.T.

    1989-06-13

    This patent describes an improved nickel-iron aluminide containing chromium and molybdenum additions to improve resistance to sulfur attack. The corrosive effects of sulfur are discussed and the chemical composition of corrosion resistant alloys is illustrated.

  1. Evaluation of corrosion resistance of various concrete reinforcing materials.

    DOT National Transportation Integrated Search

    2013-06-01

    The Vermont Agency of Transportation undertook a simple experiment to determine the corrosion : resistance ability of various reinforcing steels (rebar) that may be used in bridges and other concrete : structures. Eight types of rebar were used in th...

  2. Corrosion resistant metallic bipolar plate

    DOEpatents

    Brady, Michael P [Oak Ridge, TN; Schneibel, Joachim H [Knoxville, TN; Pint, Bruce A [Knoxville, TN; Maziasz, Philip J [Oak Ridge, TN

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  3. A Corrosion Sensor for Monitoring the Early-Stage Environmental Corrosion of A36 Carbon Steel

    PubMed Central

    Chen, Dong; Yen, Max; Lin, Paul; Groff, Steve; Lampo, Richard; McInerney, Michael; Ryan, Jeffrey

    2014-01-01

    An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2 M NaCl solution, the sensor’s normalized electrical resistance (R/R0) decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor’s normalized capacitance (C/C0) increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite. PMID:28788158

  4. Recent advances in the development of aerospace materials

    NASA Astrophysics Data System (ADS)

    Zhang, Xuesong; Chen, Yongjun; Hu, Junling

    2018-02-01

    In recent years, much progress has been made on the development of aerospace materials for structural and engine applications. Alloys, such as Al-based alloys, Mg-based alloys, Ti-based alloys, and Ni-based alloys, are developed for aerospace industry with outstanding advantages. Composite materials, the innovative materials, are taking more and more important roles in aircrafts. However, recent aerospace materials still face some major challenges, such as insufficient mechanical properties, fretting wear, stress corrosion cracking, and corrosion. Consequently, extensive studies have been conducted to develop the next generation aerospace materials with superior mechanical performance and corrosion resistance to achieve improvements in both performance and life cycle cost. This review focuses on the following topics: (1) materials requirements in design of aircraft structures and engines, (2) recent advances in the development of aerospace materials, (3) challenges faced by recent aerospace materials, and (4) future trends in aerospace materials.

  5. Electrochemical Corrosion and In Vitro Bioactivity of SiO2:ZrO2-Coated 316L Stainless Steel in Simulated Body Fluid

    NASA Astrophysics Data System (ADS)

    Srinivasan, A.; Rajendran, N.

    2015-08-01

    The effect of Si:Zr ratio on the in vitro bioactivity and electrochemical corrosion behavior of SiO2:ZrO2-mixed oxide-coated 316L stainless steel (SS) was evaluated in simulated body fluid (SBF) solution for 72, 120, and 168 h. Growth of Hydroxyapatite (HAp) was accelerated when Si content in the coating was increased. The Zr content in the coating improved the corrosion resistance of 316L SS rather than accelerating the HAp growth. When the Si:Zr ratio was 50:50, the coating exhibited significant improvement in corrosion resistance as well as HAp growth. The mechanism of HAp growth was proposed based on the change in surface zeta potential values of the coatings. Potentiodynamic polarization studies revealed about 10 and 5 times reduction in corrosion current density ( i corr) values for SiO2:ZrO2 (50:50)-coated 316L SS after 168 h of immersion compared to SiO2, ZrO2, and Si:Zr (70:30) coatings in SBF solutions thus confirming the superior corrosion resistance. The equivalent circuit parameters derived from electrochemical impedance spectroscopy studies further confirmed significant improvement in charge transfer resistance value even after 168 h of exposure.

  6. Effect of surface nanostructuring on corrosion behavior of Ti–6Al–4V alloy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kumar, Sanjeev, E-mail: sanjeevphy85@gmail.com; Ch

    Surface nanostructure was induced in Ti–6Al–4V alloy by ultrasonic shot peening (USSP) for different durations, from 15 s to 30 min, and the modified surface was characterized by optical, scanning, atomic force and transmission electron microscopy. Nano size grains were observed to form on surface of the USSPed samples and surface roughness was increased with duration of USSP. Polarization study was carried out in Ringer's solution to examine the effect of surface nanostructuring on corrosion resistance of this alloy. Electrochemical corrosion was carried out for all the USSPed specimens as well as the non-USSPed sample in Ringer's solution. Surface morphologymore » of the corroded samples was examined by SEM. In general, corrosion resistance was improved by USSP up to the duration of 15 min and there was maximum improvement in the specimen USSPed for 1 min. However, corrosion resistance was drastically reduced due to USSP for long duration of 30 min. - Highlights: •Nanostructure was induced by USSP on alloy Ti–6Al–4V of about 28 nm. •Grain refinement was confirmed by XRD and TEM. •USSP is an effective technique for the improvement in corrosion resistance. •Nanostructured surface promotes formation of protective surface layer of TiO{sub 2}.« less

  7. Electrochemical Study of Polymer and Ceramic-Based Nanocomposite Coatings for Corrosion Protection of Cast Iron Pipeline

    PubMed Central

    Ammar, Ameen Uddin; Shahid, Muhammad; Ahmed, Muhammad Khitab; Khan, Munawar; Khalid, Amir

    2018-01-01

    Coating is one of the most effective measures to protect metallic materials from corrosion. Various types of coatings such as metallic, ceramic and polymer coatings have been investigated in a quest to find durable coatings to resist electrochemical decay of metals in industrial applications. Many polymeric composite coatings have proved to be resistant against aggressive environments. Two major applications of ferrous materials are in marine environments and in the oil and gas industry. Knowing the corroding behavior of ferrous-based materials during exposure to these aggressive applications, an effort has been made to protect the material by using polymeric and ceramic-based coatings reinforced with nano materials. Uncoated and coated cast iron pipeline material was investigated during corrosion resistance by employing EIS (electrochemical impedance spectroscopy) and electrochemical DC corrosion testing using the “three electrode system”. Cast iron pipeline samples were coated with Polyvinyl Alcohol/Polyaniline/FLG (Few Layers Graphene) and TiO2/GO (graphene oxide) nanocomposite by dip-coating. The EIS data indicated better capacitance and higher impedance values for coated samples compared with the bare metal, depicting enhanced corrosion resistance against seawater and “produce water” of a crude oil sample from a local oil rig; Tafel scans confirmed a significant decrease in corrosion rate of coated samples. PMID:29495339

  8. Electrochemical Study of Polymer and Ceramic-Based Nanocomposite Coatings for Corrosion Protection of Cast Iron Pipeline.

    PubMed

    Ammar, Ameen Uddin; Shahid, Muhammad; Ahmed, Muhammad Khitab; Khan, Munawar; Khalid, Amir; Khan, Zulfiqar Ahmad

    2018-02-25

    Coating is one of the most effective measures to protect metallic materials from corrosion. Various types of coatings such as metallic, ceramic and polymer coatings have been investigated in a quest to find durable coatings to resist electrochemical decay of metals in industrial applications. Many polymeric composite coatings have proved to be resistant against aggressive environments. Two major applications of ferrous materials are in marine environments and in the oil and gas industry. Knowing the corroding behavior of ferrous-based materials during exposure to these aggressive applications, an effort has been made to protect the material by using polymeric and ceramic-based coatings reinforced with nano materials. Uncoated and coated cast iron pipeline material was investigated during corrosion resistance by employing EIS (electrochemical impedance spectroscopy) and electrochemical DC corrosion testing using the "three electrode system". Cast iron pipeline samples were coated with Polyvinyl Alcohol/Polyaniline/FLG (Few Layers Graphene) and TiO₂/GO (graphene oxide) nanocomposite by dip-coating. The EIS data indicated better capacitance and higher impedance values for coated samples compared with the bare metal, depicting enhanced corrosion resistance against seawater and "produce water" of a crude oil sample from a local oil rig; Tafel scans confirmed a significant decrease in corrosion rate of coated samples.

  9. 46 CFR 120.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Protection from wet and corrosive environments. 120.210... INSTALLATION General Requirements § 120.210 Protection from wet and corrosive environments. (a) Electrical... environments must be of suitable construction and corrosion-resistant. ...

  10. 46 CFR 120.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Protection from wet and corrosive environments. 120.210... INSTALLATION General Requirements § 120.210 Protection from wet and corrosive environments. (a) Electrical... environments must be of suitable construction and corrosion-resistant. ...

  11. 46 CFR 120.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Protection from wet and corrosive environments. 120.210... INSTALLATION General Requirements § 120.210 Protection from wet and corrosive environments. (a) Electrical... environments must be of suitable construction and corrosion-resistant. ...

  12. 46 CFR 120.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Protection from wet and corrosive environments. 120.210... INSTALLATION General Requirements § 120.210 Protection from wet and corrosive environments. (a) Electrical... environments must be of suitable construction and corrosion-resistant. ...

  13. 46 CFR 120.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 120.210... INSTALLATION General Requirements § 120.210 Protection from wet and corrosive environments. (a) Electrical... environments must be of suitable construction and corrosion-resistant. ...

  14. Surface modification of a biodegradable magnesium alloy with phosphorylcholine (PC) and sulfobetaine (SB) functional macromolecules for reduced thrombogenicity and acute corrosion resistance

    PubMed Central

    Ye, Sang-Ho; Jang, Yong-Seok; Yun, Yeo-Heung; Shankarraman, Venkat; Woolley, Joshua R.; Hong, Yi; Gamble, Lara J.; Ishihara, Kazuhiko; Wagner, William R.

    2013-01-01

    Siloxane functionalized phosphorylcholine (PC) or sulfobetaine (SB) macromolecules (PCSSi or SBSSi) were synthesized to act as surface modifying agents for degradable metallic surfaces to improve acute blood compatibility and slow initial corrosion rates. The macromolecules were synthesized using a thiol-ene radical photopolymerization technique and then utilized to modify magnesium (Mg) alloy (AZ31) surfaces via an anhydrous phase deposition of the silane functional groups. X-ray photoelectron spectroscopy surface analysis results indicated successful surface modification based on increased nitrogen and phosphorus or sulfur composition on the modified surfaces relative to unmodified AZ31. In vitro acute thrombogenicity assessment after ovine blood contact with the PCSSi and SBSSi modified surfaces showed a significant decrease in platelet deposition and bulk phase platelet activation compared with the control alloy surfaces. Potentiodynamic polarization and electrochemical impedance spectroscopy data obtained from electrochemical corrosion testing demonstrated increased corrosion resistance for PCSSi and SBSSi modified AZ31 versus unmodified surfaces. The developed coating technique using PCSSi or SBSSi showed promise in acutely reducing both the corrosion and thrombotic processes, which would be attractive for application to blood contacting devices, such as vascular stents, made from degradable Mg alloys. PMID:23705967

  15. Corrosion behaviour of electropolished AISI 316L austenitic biomaterial in physiological solution

    NASA Astrophysics Data System (ADS)

    Zatkalíková, V.; Markovičová, L.; Škorvanová, M.

    2017-11-01

    Due to suitable mechanical properties, satisfactory corrosion resistance and relatively low cost, austenitic stainless steels are important biomaterials for manufacture of implants and various medical instruments and devices. Their corrosion properties and biocompatibility are significantly affected by protective passive surface film quality, which depends on used mechanical and chemical surface treatment. This article deals with corrosion resistance of AISI 316L stainless steel, which is the most widely used Cr-Ni-Mo austenitic biomaterial. Corrosion behaviour of five various surfaces (original, electropolished, three surfaces with combined treatment finished by electropolishing) is evaluated on the bases of cyclic potentiodynamic polarization tests performed in physiological solution at the temperature of 37± 0.5 °C.

  16. Corrosion Behavior of Steels in Supercritical CO 2 for Power Cycle Applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Repukaiti, Richard; Teeter, Lucas; Ziomek-Moroz, Margaret

    In order to understand issues with corrosion of heat exchanger materials in direct supercritical carbon dioxide (sCO 2) power cycles, a series of autoclave exposure experiments and electrochemical experiments have been conducted. Corrosion behaviors of 347H stainless steel and P91 martensitic-ferrtic steel in sCO 2 environment have been compared. In autoclave exposure tests performed at 50°C- 245°C and 80 bar. Mass change measurements, surface characterization, and corrosion product analysis have been conducted to understand the corrosion behavior of steels in sCO 2 containing H 2O and O 2. Electrochemical tests performed at room temperature and 50°C, a simulation environment ofmore » water condensation phase with dissolved CO 2 was prepared to evaluate the corrosion resistance of materials. From both types of experiments, generally 347H showed higher corrosion resistance than P91.« less

  17. Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

    NASA Astrophysics Data System (ADS)

    Liu, Min; Zheng, Junyi; Lu, Yanling; Li, Zhijun; Zou, Yang; Yu, Xiaohan; Zhou, Xingtai

    2013-09-01

    Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 °C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (μ-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from μ-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 °C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys.

  18. 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.

  19. The effect of brazing parameters on corrosion behavior of brazed aluminum joints

    NASA Astrophysics Data System (ADS)

    Ghasimakbari, Farzam; Hadian, Ali Mohammad; Ershadrad, Soheil; Omidazad, Amir Mansour

    2018-01-01

    Fluid transmission pipes made of aluminum are widely used in petrochemical industries. For many applications, they have to be brazed to each other. The brazed joints, in many cases, are encountered with corrosive medias. This paper reports a part of a work to investigate the corrosion behavior of brazed AA6061 using AA4047 as filler metal with and without the use of flux under different brazing atmospheres. The samples brazed under air, vacuum, argon, and hydrogen atmospheres. The interfacial area of the joints was examined to ensure being free of any defects. The sides of each test piece were covered with an insulator and the surface of the joint was encountered to polarization test. The results revealed a significant difference of corrosion resistance. The samples that brazed under argon and hydrogen atmospheres had better corrosion resistance than other samples. The microstructure of the corroded joints revealed that the presence of defects, impurities due to use of flux and depth of filter metal penetration in base metal are crucial variables on the corrosion resistance of the joints.

  20. Advanced Materials and Multifunctional Structures for Aerospace Vehicles

    DTIC Science & Technology

    2006-10-01

    environment and sulfur in fuels, leading to deterioration of engine hot section components, including the turbine and combustor. As such, development and...barrier coatings for high temperature turbine components are in high demand. 3.1 Hard Coatings for Erosion, Wear and Corrosion Protection A coating that...C-N coatings showed that increasing carbon content in the coating reduced the corrosion resistance in 1 N H2SO4 solution102; nevertheless, it was

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