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Sample records for actuators corrosion protection

  1. Corrosion protection

    DOEpatents

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

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

  2. Corrosion protection by anaerobiosis.

    PubMed

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

    2001-01-01

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

  3. Smart Coatings for Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  4. CORROSION PROTECTION OF ALUMINUM

    DOEpatents

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

    1963-07-01

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

  5. Corrosion Protection of Aluminum

    DOEpatents

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

    1963-07-01

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

  6. Space Shuttle Corrosion Protection Performance

    NASA Technical Reports Server (NTRS)

    Curtis, Cris E.

    2007-01-01

    The reusable Manned Space Shuttle has been flying into Space and returning to earth for more than 25 years. The launch pad environment can be corrosive to metallic substrates and the Space Shuttles are exposed to this environment when preparing for launch. The Orbiter has been in service well past its design life of 10 years or 100 missions. As part of the aging vehicle assessment one question under evaluation is how the thermal protection system and aging protective coatings are performing to insure structural integrity. The assessment of this cost resources and time. The information is invaluable when minimizing risk to the safety of Astronauts and Vehicle. This paper will outline a strategic sampling plan and some operational improvements made by the Orbiter Structures team and Corrosion Control Review Board.

  7. 49 CFR 193.2625 - Corrosion protection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or...

  8. 49 CFR 193.2625 - Corrosion protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or...

  9. 49 CFR 193.2625 - Corrosion protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or...

  10. 49 CFR 193.2625 - Corrosion protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or...

  11. Migrating corrosion inhibitor protection of concrete

    SciTech Connect

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  12. Corrosion Protection by Calcite-Type Coatings

    DTIC Science & Technology

    1989-10-01

    CORROSION PROTECTION BY CALCITE -TYPE COATINGS OCTOBER, 1989 Prepared by: OCEAN CITY RESEARCH CORPORATION Tennessee Avenue & Beach Thorofare Ocean...REPORT DATE OCT 1989 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Corrosion Protection by Calcite -Type Coatings 5a. CONTRACT... calcite -type coatings to segregated seawater ballast tanks. If perfected, a calcite coating approach could substantially reduce the cost of corrosion

  13. 49 CFR 192.461 - External corrosion control: Protective coating.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion...

  14. 49 CFR 192.461 - External corrosion control: Protective coating.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion...

  15. 49 CFR 192.461 - External corrosion control: Protective coating.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion...

  16. 49 CFR 192.461 - External corrosion control: Protective coating.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion...

  17. 49 CFR 192.461 - External corrosion control: Protective coating.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion...

  18. Silica nanocontainers for active corrosion protection.

    PubMed

    Maia, Frederico; Tedim, João; Lisenkov, Aleksey D; Salak, Andrei N; Zheludkevich, Mikhail L; Ferreira, Mário G S

    2012-02-21

    Novel self-healing protective coatings with nanocontainers of corrosion inhibitors open new opportunities for long-term anticorrosion protection of different metallic materials. In this paper a new type of functional nanoreservoir based on silica nanocapsules (SiNC) synthesized and loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) in a one-stage process is reported for the first time. Unlike conventional mesoporous silica nanoparticles, SiNC possess an empty core and shell with gradual mesoporosity, arising from the particular conditions of the synthetic route adopted, which confers significant loading capacity and allows prolonged and stimuli-triggered release of the inhibiting species. The kinetics of inhibitor release was studied at different pH values and concentrations of NaCl. The results show a clear dependence of the release profiles on corrosion relevant triggers such as pH and Cl(-) concentration. When SiNC loaded with MBT are dispersed in NaCl solution, there is a significant decrease of the corrosion activity on aluminium alloy 2024. More importantly, when SiNC-MBT is added to a conventional water-based coating formulation, the modified coating hampers corrosion activity at the metal interface, better than in the case of direct addition of corrosion inhibitor. Furthermore, self-healing is observed before and after artificially inflicting defects in the modified coatings. As a result, the developed nanocontainers show high potential to be used in new generation of active protective coatings.

  19. Silica nanocontainers for active corrosion protection

    NASA Astrophysics Data System (ADS)

    Maia, Frederico; Tedim, João; Lisenkov, Aleksey D.; Salak, Andrei N.; Zheludkevich, Mikhail L.; Ferreira, Mário G. S.

    2012-02-01

    Novel self-healing protective coatings with nanocontainers of corrosion inhibitors open new opportunities for long-term anticorrosion protection of different metallic materials. In this paper a new type of functional nanoreservoir based on silica nanocapsules (SiNC) synthesized and loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) in a one-stage process is reported for the first time. Unlike conventional mesoporous silica nanoparticles, SiNC possess an empty core and shell with gradual mesoporosity, arising from the particular conditions of the synthetic route adopted, which confers significant loading capacity and allows prolonged and stimuli-triggered release of the inhibiting species. The kinetics of inhibitor release was studied at different pH values and concentrations of NaCl. The results show a clear dependence of the release profiles on corrosion relevant triggers such as pH and Cl- concentration. When SiNC loaded with MBT are dispersed in NaCl solution, there is a significant decrease of the corrosion activity on aluminium alloy 2024. More importantly, when SiNC-MBT is added to a conventional water-based coating formulation, the modified coating hampers corrosion activity at the metal interface, better than in the case of direct addition of corrosion inhibitor. Furthermore, self-healing is observed before and after artificially inflicting defects in the modified coatings. As a result, the developed nanocontainers show high potential to be used in new generation of active protective coatings.

  20. Corrosion protection with eco-friendly inhibitors

    NASA Astrophysics Data System (ADS)

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3-2 and NO-3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10-4 M 93% efficiency was exhibited at this concentration.

  1. Corrosion protection of reusable surgical instruments.

    PubMed

    Shah, Sadiq; Bernardo, Mildred

    2002-01-01

    To understand the corrosion properties of surgical scissors, 416 stainless steel disks and custom electrodes were used as simulated surfaces under various conditions. These simulated surfaces were exposed to tap water and 400-ppm synthetic hard water as Ca2CO3 under different conditions. The samples were evaluated by various techniques for corrosion potential and the impact of environmental conditions on the integrity of the passive film. The electrodes were used to monitor the corrosion behavior by potentiodynamic polarization technique in water both in the presence and absence of a cleaning product. The surface topography of the 416 stainless steel disks was characterized by visual observations and scanning electron microscopy (SEM), and the surface chemistry of the passive film on the surface of the scissors was characterized by x-ray photoelectron spectroscopy (XPS). The results suggest that surgical instruments made from 416 stainless steel are not susceptible to uniform corrosion; however, they do undergo localized corrosion. The use of suitable cleaning products can offer protection against localized corrosion during the cleaning step. More importantly, the use of potentiodynamic polarization techniques allowed for a quick and convenient approach to evaluate the corrosion properties of surgical instruments under a variety of simulated-use environmental conditions.

  2. Corrosion protective coating for metallic materials

    DOEpatents

    Buchheit, Rudolph G.; Martinez, Michael A.

    1998-01-01

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds.

  3. Corrosion protective coating for metallic materials

    DOEpatents

    Buchheit, R.G.; Martinez, M.A.

    1998-05-26

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

  4. 49 CFR 193.2625 - Corrosion protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Corrosion protection. 193.2625 Section 193.2625 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY LIQUEFIED NATURAL GAS...

  5. Corrosion protection for silver reflectors

    DOEpatents

    Arendt, Paul N.; Scott, Marion L.

    1991-12-31

    A method of protecting silver reflectors from damage caused by contact with gaseous substances which are often present in the atmosphere and a silver reflector which is so protected. The inventive method comprises at least partially coating a reflector with a metal oxide such as aluminum oxide to a thickness of 15 .ANG. or less.

  6. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: Cathodic protection. 192.463 Section 192.463 Transportation Other Regulations Relating to Transportation (Continued... for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a) Each...

  7. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: Cathodic protection. 192.463 Section 192.463 Transportation Other Regulations Relating to Transportation (Continued... for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a) Each...

  8. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: Cathodic protection. 192.463 Section 192.463 Transportation Other Regulations Relating to Transportation (Continued... for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a) Each...

  9. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Cathodic protection. 192.463 Section 192.463 Transportation Other Regulations Relating to Transportation (Continued... for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a) Each...

  10. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: Cathodic protection. 192.463 Section 192.463 Transportation Other Regulations Relating to Transportation (Continued... for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a) Each...

  11. Molybdate Coatings for Protecting Aluminum Against Corrosion

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; MacDowell, Louis G.

    2005-01-01

    Conversion coatings that comprise mixtures of molybdates and several additives have been subjected to a variety of tests to evaluate their effectiveness in protecting aluminum and alloys of aluminum against corrosion. Molybdate conversion coatings are under consideration as replacements for chromate conversion coatings, which have been used for more than 70 years. The chromate coatings are highly effective in protecting aluminum and its alloys against corrosion but are also toxic and carcinogenic. Hexavalent molybdenum and, hence, molybdates containing hexavalent molybdenum, have received attention recently as replacements for chromates because molybdates mimic chromates in a variety of applications but exhibit significantly lower toxicity. The tests were performed on six proprietary formulations of molybdate conversion coatings, denoted formulations A through F, on panels of aluminum alloy 2024-T3. A bare alloy panel was also included in the tests. The tests included electrochemical impedance spectroscopy (EIS), measurements of corrosion potentials, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS).

  12. Materials corrosion and protection from first principles

    NASA Astrophysics Data System (ADS)

    Johnson, Donald F.

    Materials erode under environmental stresses such as high temperature, high pressure, and mechanical shock/stress, but erosion is often exacerbated by chemical corrosion. In this dissertation, periodic density functional theory (DFT) is employed to simulate interfacial adhesion, absorption kinetics, bulk diffusion, and other material phenomena (e.g., hydrogen-enhanced decohesion and shock-induced phase changes) with the intention of understanding corrosion and subsequent failure processes and guiding the design of new protective coatings. This work examines corrosion and/or protection of materials ( i.e., Fe, Ni, W) with important applications: structural steel, gun tubes, high-pressure oil recovery vessels, jet engine turbine blades, and fusion reactor walls. We use DFT to model the pressure-induced, bcc-to-hcp phase transformation in Fe, in which a new low energy pathway is predicted exhibiting nonadiabatic behavior coupling magnetic and structural changes. Protection of steel is addressed in two aspects: interfacial adhesion of protective coatings and assessment of corrosion resistance provided by a surface alloy. First, the current chrome-coated steel system is examined where extremely strong adhesion is predicted at the Cr/Fe interface originating in strong spin correlations. A ceramic coating, SiC, is considered as a possible replacement for Cr. Strong adhesion is predicted, especially for C-Fe interfacial bonds. To assess corrosion resistance, we model ingress of two common corrosive elements, H and C, into two Fe alloys, FeAl and Fe3Si. Adsorption and absorption thermodynamics and kinetics, as well as bulk dissolution and diffusion are calculated in order to determine whether these two alloys can inhibit uptake of H and C. Relative to pure Fe, dissolved H and C are less stable in the alloys, as the dissolution enthalpy is predicted to be more endothermic. Overall, the energy barriers and rate constants for adsorbed H/C diffusing into Fe3Si subsurface layers

  13. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  14. Accelerated Test Method for Corrosion Protective Coatings Project

    NASA Technical Reports Server (NTRS)

    Falker, John; Zeitlin, Nancy; Calle, Luz

    2015-01-01

    This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

  15. Electrostatic Discharge (ESD) Protection for a Laser Diode Ignited Actuator

    SciTech Connect

    SALAS, FREDERICK J.; SANCHEZ, DANIEL H.; WEINLEIN, JOHN HARVEY

    2003-06-01

    The use of laser diodes in devices to ignite pyrotechnics provides unique new capabilities including the elimination of electrostatic discharge (ESD) pulses entering the device. The Faraday cage formed by the construction of these devices removes the concern of inadvertent ignition of the energetic material. However, the laser diode itself can be damaged by ESD pulses, therefore, to enhance reliability, some protection of the laser diode is necessary. The development of the MC4612 Optical Actuator has included a circuit to protect the laser diode from ESD pulses including the ''Fisher'' severe human body ESD model. The MC4612 uses a laser diode and is designed to replace existing hot-wire actuators. Optical energy from a laser diode, instead of electrical energy, is used to ignite the pyrotechnic. The protection circuit is described along with a discussion of how the circuit design addresses and circumvents the historic 1Amp/1Watt requirement that has been applicable to hot-wire devices.

  16. Offshore marine structure with corrosion protection

    SciTech Connect

    Rutherford, D.A.; Barr, B.D.; Rommelmann, D.W.

    1986-12-16

    This patent describes a marine structure having a deck and a rotatable drill string for drilling wellbores into the floor of a body of water; a jacket comprised of corrodible metallic members including support legs which are mutually interconnected with cross braces, and which jacket rests on the floor and supports the deck above the water's surface, a drilling template incorporated into the jacket to accommodate drilling conductors for guiding the rotatable drill string which is lowered from the deck to form a vertical wellbore, the drilling template including vertically aligned elongated conductor guides arranged in a horizontal pattern to define a drill conductor array comprised of external conductors, which encompass at least one internal conductor, a cathodic protection system protecting the corrodible metallic members of the marine structure comprising a first sacrificial anode system disposed on discrete submerged jacket members to afford corrosion protection to the jacket members as well as to submerged sections of the drill conductor array, and other sacrificial anodes removably carried on at least one internal conductor to supplement the cathodic protection afforded by the first sacrificial anodes.

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    indicators, inhibitors and self-healing agents. This allows the incorporation of autonomous corrosion control functionalities, such as corrosion detection and inhibition as well as the self-healing of mechanical damage, into coatings. This paper presents technical details on the characterization of inhibitor-containing particles and their corrosion inhibitive effects using electrochemical and mass loss methods.Three organic environmentally friendly corrosion inhibitors were encapsulated in organic microparticles that are compatible with desired coatings. The release of the inhibitors from the microparticles in basic solution was studied. Fast release, for immediate corrosion protection, as well as long-term release for continued protection, was observed.The inhibition efficacy of the inhibitors, incorporated directly and in microparticles, on carbon steel was evaluated. Polarization curves and mass loss measurements showed that, in the case of 2MBT, its corrosion inhibition effectiveness was greater when it was delivered from microparticles.

  18. Smart Coatings for Launch Site Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.

    2014-01-01

    Smart, environmentally friendly paint system for early corrosion detection, mitigation, and healing that will enable supportability in KSC launch facilities and ground systems through their operational life cycles. KSC's Corrosion Technology Laboratory is developing a smart, self-healing coating that can detect and repair corrosion at an early stage. This coating is being developed using microcapsules specifically designed to deliver the contents of their core when corrosion starts.

  19. The Corrosion Protection of Metals by Ion Vapor Deposited Aluminum

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1993-01-01

    A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

  20. The corrosion protection of metals by ion vapor deposited aluminum

    SciTech Connect

    Danford, M.D.

    1993-10-01

    A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

  1. Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.

    PubMed

    Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Séverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

    2012-11-01

    A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films.

  2. Redox-responsive self-healing for corrosion protection.

    PubMed

    Vimalanandan, Ashokanand; Lv, Li-Ping; Tran, The Hai; Landfester, Katharina; Crespy, Daniel; Rohwerder, Michael

    2013-12-23

    Raspberry-shaped redox-responsive capsules for storing corrosion inhibitors are introduced, targeted to solve the drawbacks of conducting-polymer-based coating systems for corrosion protection. These capsules synthesized via the miniemulsion technique have a remarkable release property upon reduction (onset of corrosion) and cease release upon reoxidation (passivation of the defect). The self-healing capability is demonstrated by application of these capsules as part of a composite coating on zinc.

  3. Corrosion Protection for Space and Beyond

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina

    2007-01-01

    Florida is home to NASA's Launch Operations Center. Since its establishment in July 1962, the spaceport has served as the departure gate for every American manned mission and hundreds of advanced scientific spacecraft under the Launch Services Program. The center was renamed the John F. Kennedy Space Center in late 1963 to honor the president who put America on the path to the moon. Today, NASA is on the edge of a bold new chaIlenge: the ConsteIlation Program. ConsteIlation is a NASA program to create a new generation of spacecraft for human spaceflight, consisting primarily of the Ares I and Ares V launch vehicles, the Orion crew capsule, the Earth Departure stage and the Lunar access module. These spacecraft will be capable of performing a variety of missions, from Space Station resupply to lunar landings. The ambitious new endeavor caIls for NASA to return human explorers to the moon and then venture even farther, to Mars and beyond. As the nation's premier spaceport, Kennedy Space Center (KSC) will playa critical role in this new chapter in exploration, particularly in the conversion of the launch facilities to accommodate the new launch vehicles. To prepare for this endeavor, the launch site and facilities for the next generation of crew and cargo vehicles must be redesigned, assembled and tested. One critical factor that is being carefuIly considered during the renovation is protecting the new facilities and structures from corrosion and deterioration.

  4. Biobased polymers for corrosion protection of metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anticorrosive biobased polymers were developed in our lab. We isolated an exopolysaccharide produced by a microbe that, when coated on metal substrates, exhibited unique corrosion inhibition. Corrosion is a worldwide problem and impacts the economy, jeopardizes human health and safety, and impedes t...

  5. Microencapsulation Technologies for Corrosion Protective Coating Applications

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Buhrow, Jerry; Jolley, Scott; Calle, Luz; Pearman, Benjamin; Zhang, Xuejun

    2015-01-01

    Microencapsulation technologies for functional smart Coatings for autonomous corrosion control have been a research area of strong emphasis during the last decade. This work concerns the development of pH sensitive micro-containers (microparticles and microcapsules) for autonomous corrosion control. This paper presents an overview of the state-of-the-art in the field of microencapsulation for corrosion control applications, as well as the technical details of the pH sensitive microcontainer approach, such as selection criteria for corrosion indicators and corrosion inhibitors; the development and optimization of encapsulation methods; function evaluation before and after incorporation of the microcontainers into coatings; and further optimization to improve coating compatibility and performance.

  6. 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.

  7. Corrosion-protective coatings from electrically conducting polymers

    SciTech Connect

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

    1991-12-31

    In a joint research effort involving the Kennedy Space Center and the Los Alamos National Laboratory, electrically conductive polymer coatings have been developed as corrosion-protective coatings for metal surfaces. At the Kennedy Space Center, the launch environment consists of marine, severe solar, and intermittent high acid/elevated temperature conditions. Electrically conductive polymer coatings have been 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.

  8. Evaluation of several corrosion protective coating systems on aluminum

    NASA Technical Reports Server (NTRS)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  9. Evaluation of several corrosion protective coating systems on aluminum

    SciTech Connect

    Higgins, R.H.

    1981-02-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 h. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  10. Applications of intermittent cathodic protection for control of rebar corrosion

    SciTech Connect

    Ziomek-Moroz, Margaret; Cramer, Stephen D.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Russell, James H.; Holcomb, Gordon R.; | Windisch, C.F., Jr.; Soltesz, S.M.

    2002-01-01

    Rebar in concrete structures is susceptible to chloride-induced corrosion. Impressed current cathodic protection (ICCP) is frequently used to protect rebar against corrosion,. To take advantage of rebar passivity in concrete after ICCP is turned off, the Albany Research Center, in collaboration with the Oregon Department of Transportation and Pacific Northwest National Laboratory, is investigating applications of intermittent cathodic protection corrosion as a means for advancing corrosion control of reinforced concrete structures while extending the service life of thermal-sprayed zinc anodes. Corrosion rates of rebar in deaerated and oxygenated simulated pore water and quartz sand saturated with simulated pore water at pH 7 and 13 were determined using electrochemical and mass loss techniques. The rebar was passive at pH 13, but measurable corrosion occurred at pH 7. The use of sand prevented convective transport of reactants to and from the rebar, thereby substantially reducing the corrosion rate. In-situ Surface Enhanced Raman Spectroscopy (SERS) results indicated the presence of Fe304 and Fe (OH)2 on the rebar surface depending upon the polarization conditions. The amount of Fe304 decreased while Fe (OH)2 increased as the time of cathodic polarization increased.

  11. Corrosion protection of aluminum metal-matrix composites

    SciTech Connect

    Greene, H.J.; Mansfeld, F.

    1997-12-01

    Corrosion protection of aluminum metal-matrix composites (MMC) by anodizing treatments was investigated. Electrochemical behavior of MMC without protection also was investigated. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements were used to characterize the properties of protective surface layers. Materials studied were Al 6061/SiC, alloy A356/SiC, Al 2009/SiC, Al 2014/Al{sub 2}O{sub 3} and Al 6061/Al{sub 2}O{sub 3} with various reinforcement concentrations. The MMC had similar corrosion (E{sub corr}) and pitting (E{sub pit}) potentials as the matrix alloy. The cathodic current density for oxygen reduction in 0.5% N sodium chloride increased for Al 6061/SiC MMC with reinforcement concentration, which was attributed to electrochemically active interfaces between the matrix and the reinforcement particles. Anodizing and hot-water sealing were less effective for MMC than for the matrix aluminum alloys. The reinforcement particles produced a more porous structure of the anodized layer for MMC. Improved results were noted for dichromate sealing, where chromium (Cr{sup 6+}) in the pores of the outer oxide acted as an inhibitor. The effectiveness of corrosion protection methods decreased with increasing reinforcement concentration and was a function of the matrix alloy but not of the reinforcement material. The observed reduction in corrosion protection was believed to result from corrosion-susceptible interfaces formed between the reinforcement particles and the matrix.

  12. Corrosion protection of equipment in recirculating water supply systems

    SciTech Connect

    Teslya, B.M.; Burlov, V.V.; Shadrina, A.N.; Vyazhevich, A.V.

    1983-01-01

    The metals in the condensers, coolers and heat exchangers of petroleum refineries and petrochemical plants are subject to corrosion, and this is responsible for forced shutdowns. This paper notes that the shortest service life is given by the carbon and silicon-manganese steels, the longest by the chrome-nickel steels and arsenic-alloyed brasses. It reports that a high level of protection is provided by the use of the inhibitor IKB-4V at the Industrial Association ''Novopolotsknefteorgsintez'' and a so-called complex corrosion retarder consisting of a mixture of zinc sulfate and orthophosphoric acid at the Novo-Ufa refinery. It also points out that the most desirable method for corrosion protection of cooling towers, from the standpoint of technical and economic justification, is the use of protective paint coatings. It urges scientific research and design organizations and also the plants of the petroleum refining and petrochemical industry to take a multipronged approach in solving problems in corrosion control. It is pointed out that protection by inhibitors must be combined with the use of paints and other types of organic and inorganic coatings, protection against salt deposition and biological overgrowth, and the rational use of corrosion-resistant materials of construction.

  13. Agricultural Polymers for Corrosion Protection of Metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion is one of the most serious and challenging problems faced worldwide by industry. When metals come in contact with different environments such as air, water, chemical products and pollutants, they begin to degrade as the metal interacts with its environment. This research investigates the...

  14. Chemical conversion coating for protecting magnesium alloys from corrosion

    DOEpatents

    Bhargava, Gaurang; Allen, Fred M.; Skandan, Ganesh; Hornish, Peter; Jain, Mohit

    2016-01-05

    A chromate-free, self-healing conversion coating solution for magnesium alloy substrates, composed of 10-20 wt. % Mg(NO.sub.3).sub.2.6H.sub.2O, 1-5 wt. % Al(NO.sub.3).sub.3.9H.sub.2O, and less than 1 wt. % of [V.sub.10O.sub.28].sup.6- or VO.sub.3.sup.- dissolved in water. The corrosion resistance offered by the resulting coating is in several hundreds of hours in salt-spray testing. This prolonged corrosion protection is attributed to the creation of a unique structure and morphology of the conversion coating that serves as a barrier coating with self-healing properties. Hydroxoaluminates form the backbone of the barrier protection offered while the magnesium hydroxide domains facilitate the "slow release" of vanadium compounds as self-healing moieties to defect sites, thus providing active corrosion protection.

  15. The corrosion protection of aluminum by various anodizing treatments

    NASA Technical Reports Server (NTRS)

    Danford, Merlin D.

    1989-01-01

    Corrosion protection to 6061-T6 aluminum, afforded by both teflon-impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5 percent NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved superior to that afforded by Polylube at each pH, with corrosion protection by the hard-anodized, water-sealed coat at pH 9.5 providing the best protection. Electrochemical work in each case was corroborated by microscopic examination of the coats after exposure. Corrosion protection by Tufram at pH 9.5 was most comparable to that of the hard-anodized samples, although pitting and some cracking of the coat did occur.

  16. 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....

  17. 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....

  18. 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....

  19. 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....

  20. 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....

  1. Protect nuclear plant fasteners from boric acid corrosion

    SciTech Connect

    Moisidis, N.; Popescu, M.; Ratiu, M. )

    1992-03-01

    Boric acid corrosion of pump and valve fasteners in pressurized water reactor (PWR) power plants can be prevented by implementing appropriate fastener steel replacement and extended inspections to detect and correct the cause of leakage. In this paper a three-phase corrosion protection program based on system operability, outage-related accessibility, and cost of fastener replacement versus maintenance frequency increase is presented. A selection criteria for fastener material is also presented. Degradation or failure of pressure retaining fasteners at pumps and valves has been reported in several areas exposed to leakage of closures in long-term service. The resulting boric acid corrosion experienced in PWR systems is defined as an accelerated process produced when water evaporates from leaking coolant. The primary detrimental effect of boric acid leakage is wastage (or general dissolution corrosion) of low-alloy carbon steel fasteners.

  2. Measurement of corrosion under insulation and effectiveness of protective coatings

    SciTech Connect

    Abayarathna, D.; Ashbaugh, W.G.; Kane, R.D.; McGowan, N. Heimann, B.

    1997-08-01

    A laboratory cell set-up was designed and constructed for the simulation of corrosion under insulation (CUI) on a pipe section at elevated temperature. The CUI cell consisted of six carbon steel ring specimens separated by insulation spacers and held together by blind flanged pipe sections on both ends. Thermal insulation which was placed around the testing section provided the annular space to retain the test environment. The ring specimens were used as test electrodes in two separate electrochemical cells. One cell was used as the control while the other was used to test applied protective coatings. Corrosion measurements were made using both electrochemical polarization resistance and mass loss data under isothermal and cyclic wet/dry test conditions. The test cell was used to (1) successfully simulate CUI in the laboratory, (2) evaluate the corrosivity and different modes of corrosion observed with CUI and (3) evaluate proprietary coatings for minimizing CUI under simulated CUI conditions.

  3. Boron nitride nanosheets as oxygen-atom corrosion protective coatings

    SciTech Connect

    Yi, Min; Shen, Zhigang; Zhao, Xiaohu; Liang, Shuaishuai; Liu, Lei

    2014-04-07

    The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion.

  4. The corrosion protection of 2219-T87 aluminum by anodizing

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1991-01-01

    Various types of anodizing coatings were studied for 2219-T87 aluminum. These include both type II and type III anodized coats which were water sealed and a newly developed and proprietary Magnaplate HCR (TM) coat. Results indicate that type II anodizing is not much superior to type II anodizing as far as corrosion protection for 2219-T87 aluminum is concerned. Magnaplate HCR (TM) coatings should provide superior corrosion protection over an extended period of time using a coating thickness of 51 microns (2.0 mils).

  5. Boron nitride nanosheets as oxygen-atom corrosion protective coatings

    NASA Astrophysics Data System (ADS)

    Yi, Min; Shen, Zhigang; Zhao, Xiaohu; Liang, Shuaishuai; Liu, Lei

    2014-04-01

    The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion.

  6. Renewal of corrosion protection of coated aluminum after welding

    NASA Technical Reports Server (NTRS)

    Higgins, R. H.

    1969-01-01

    Effectiveness of conversion coatings designed to protect aluminum alloys against atmospheric corrosion is reduced after exposure to high temperature or welding. Damaged coating should be manually stripped six inches from the weld and then recoated by sponge or spray with the original solution.

  7. Coating protects magnesium-lithium alloys against corrosion

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Coating protects newly developed magnesium-lithium alloys against corrosion. The procedure includes heating the ingots in a salt bath and rolling them to the desired sheet thickness. The black coating, which is tough though thin and ductile, is derived mainly from chromium.

  8. Corrosion protection of aluminum alloys in contact with other metals

    NASA Technical Reports Server (NTRS)

    Kuster, C. A.

    1969-01-01

    Study establishes the quality of chemical and galvanized protection afforded by anodized and aldozided coatings applied to test panels of various aluminum alloys. The test panels, placed in firm contact with panels of titanium alloys, were subjected to salt spray tests and visually examined for corrosion effect.

  9. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Operation and maintenance of corrosion... UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.31 Operation and maintenance of corrosion protection. All owners and operators of steel UST systems with corrosion protection must comply with...

  10. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Operation and maintenance of corrosion... UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.31 Operation and maintenance of corrosion protection. All owners and operators of steel UST systems with corrosion protection must comply with...

  11. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Operation and maintenance of corrosion... UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.31 Operation and maintenance of corrosion protection. All owners and operators of steel UST systems with corrosion protection must comply with...

  12. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Operation and maintenance of corrosion... UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.31 Operation and maintenance of corrosion protection. All owners and operators of steel UST systems with corrosion protection must comply with...

  13. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Operation and maintenance of corrosion... UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.31 Operation and maintenance of corrosion protection. All owners and operators of steel UST systems with corrosion protection must comply with...

  14. Mullite coatings for corrosion protection of silicon carbide

    SciTech Connect

    Mulpuri, R.; Sarin, V.K.

    1995-08-01

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can satisfy the stringent requirements imposed by such applications. Chemical Vapor Deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and a good coefficient of thermal expansion match with SiC are being investigated as a potential candidate. Since mullite has never been successfully grown via CVD, the thermodynamics and kinetics of its formation were initially established and used as a guideline in determining the initial process conditions. Process optimization was carried out using an iterative process of theoretical analysis and experimental work coupled with characterization and testing. The results of theoretical analysis and the CVD formation characteristics of mullite are presented.

  15. MOSFET Switching Circuit Protects Shape Memory Alloy Actuators

    NASA Technical Reports Server (NTRS)

    Gummin, Mark A.

    2011-01-01

    A small-footprint, full surface-mount-component printed circuit board employs MOSFET (metal-oxide-semiconductor field-effect transistor) power switches to switch high currents from any input power supply from 3 to 30 V. High-force shape memory alloy (SMA) actuators generally require high current (up to 9 A at 28 V) to actuate. SMA wires (the driving element of the actuators) can be quickly overheated if power is not removed at the end of stroke, which can damage the wires. The new analog driver prevents overheating of the SMA wires in an actuator by momentarily removing power when the end limit switch is closed, thereby allowing complex control schemes to be adopted without concern for overheating. Either an integral pushbutton or microprocessor-controlled gate or control line inputs switch current to the actuator until the end switch line goes from logic high to logic low state. Power is then momentarily removed (switched off by the MOSFET). The analog driver is suited to use with nearly any SMA actuator.

  16. Graphene coatings for protection against microbiologically induced corrosion

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Ajay

    Microbiologically induced corrosion (MIC) is a special form of electrochemical corrosion where micro-organisms affect the local environmental conditions at the metal-electrolyte interface by forming a stable biofilm. The biofilm introduces localized concentration cells, which accelerate the electrochemical corrosion rates. MIC has been found to affect many industrial systems such as sewage waste water pipes, heat exchangers, ships, underwater pipes etc. It has been traditionally eradicated by physical, biochemical and surface protection methods. The cleaning methods and the biocidal deliveries are required periodically and don't provide a permanent solution to the problem. Further, the use of biocides has been harshly criticized by environmentalists due to safety concerns associated with their usage. Surface based coatings have their own drawback of rapid degradation under harsh microbial environments. This has led to the exploration of thin, robust, inert, conformal passivation coatings for the protection of metallic surfaces from microbiologically induced corrosion. Graphene is a 2D arrangement of carbon atoms in a hexagonal honeycomb lattice. The carbon atoms are bonded to one another by sp2 hybridization and each layer of the carbon ring arrangement spans to a thickness of less than a nm. Due to its unique 2D arrangement of carbon atoms, graphene exhibits interesting in-plane and out of plane properties that have led to it being considered as the material for the future. Its excellent thermal, mechanical, electrical and optical properties are being explored in great depth to understand and realize potential applications in various technological realms. Early studies have shown the ability of bulk and monolayer graphene to protect metallic surfaces from air oxidation and solution based galvanic corrosion processes for short periods. However, the role of graphene in resisting MIC is yet to be determined, particularly over the long time spans characteristic of

  17. 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....

  18. 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....

  19. 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....

  20. 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....

  1. 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....

  2. Corrosion protection of metals by silane surface treatment

    NASA Astrophysics Data System (ADS)

    Zhu, Danqing

    2005-07-01

    The need for toxic chromate replacements in metal-finishing industries has prompted an intensive search for replacement technologies in recent years. Among the replacements that have been proposed, those that are based upon the use of organofunctional silanes rank very high in terms of performance, broad applicability as well as ease of application. This dissertation presents a four-part work: (1) structural characterization of silane films on metals, (2) mechanism studies of silane-treated metal systems, (3) development of water-based silane systems, and (4) measurements of other properties of silane films. In part 1, silane films, i.e., bis-[triethoxysilylpropyl]tetrasulfide (bis-sulfur silane) and bis-[trimethoxysilylpropyl]amine (bis-amino silane) were deposited on AA 2024-T3 and were characterized mainly using reflection-absorption Fourier-transform infrared spectroscopy (FTIR-RA) and electrochemical impedance spectroscopy (EIS) techniques. In part 2, the mechanistic study of corrosion protection of AA 2024-T3 by bis-sulfur silane film was carried out. In summation, the following two factors play critical roles in the corrosion protection of AA 2024-T3: (1) the formation of a highly crosslinked interfacial layer, and (2) high water resistance of silane films. The former inhibits corrosion in the following two ways: (1) blocking favorable sites for water adsorption by the formation of AlOSi bonds at the interface which effectively reduces the tendency of aqueous corrosion; and (2) bonding tightly to the metal and thus restricting transportation of the existing corrosion products away from their original sites which hinders pit growth. It should be noted that a high density of AlOSi bonds can be obtained employing bis-silanes rather than mono-silanes. A high water resistance makes water penetration difficult in silane films. This is essential for preventing AlOSi bonds from hydrolysis. In part 3, test results for newly-developed water-based silane systems were

  3. Corrosion protection of prestressing systems in concrete bridges. Final report

    SciTech Connect

    Perenchio, W.F.; Fraczek, J.; Pfeifer, D.W.

    1989-02-01

    The report reviews techniques and materials to provide enhanced corrosion protection for prestressing steel and its associated metallic hardware in pretensioned and post-tensioned concrete bridges. A year-long, accelerated corrosion test program on epoxy-coated strand, polyethylene duct, epoxy-coated steel duct, epoxy-coated anchorage hardware, grouts modified with silica fume and calcium nitrite, and heat-shrink tubing for sealing post-tensioning duct joints, together with traditional materials was undertaken on pretensioned and post-tensioned members. The use of newer corrosion-resistant duct materials and watertight duct joints was found to be essential since all three grout formulations were highly permeable to chloride at joints sealed with duct tape or after the traditional steel ducts corroded. Bond tests indicated that polyethylene duct and epoxy-coated steel duct can provide structurally composite behavior between the concrete and grout. Friction and abrasion tests demonstrated that a high coefficient of friction and abrasion damage may result if epoxy-coated strand is used in corrugated metal duct with a small radius of curvature.

  4. 46 CFR 183.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Protection from wet and corrosive environments. 183.210... corrosive environments. (a) Electrical equipment used in the following locations must be dripproof: (1) A.... (c) Electrical equipment exposed to corrosive environments must be of suitable construction...

  5. 46 CFR 183.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Protection from wet and corrosive environments. 183.210... corrosive environments. (a) Electrical equipment used in the following locations must be dripproof: (1) A.... (c) Electrical equipment exposed to corrosive environments must be of suitable construction...

  6. 46 CFR 183.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Protection from wet and corrosive environments. 183.210... corrosive environments. (a) Electrical equipment used in the following locations must be dripproof: (1) A.... (c) Electrical equipment exposed to corrosive environments must be of suitable construction...

  7. 46 CFR 183.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 183.210... corrosive environments. (a) Electrical equipment used in the following locations must be dripproof: (1) A.... (c) Electrical equipment exposed to corrosive environments must be of suitable construction...

  8. 46 CFR 183.210 - Protection from wet and corrosive environments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Protection from wet and corrosive environments. 183.210... corrosive environments. (a) Electrical equipment used in the following locations must be dripproof: (1) A.... (c) Electrical equipment exposed to corrosive environments must be of suitable construction...

  9. Corrosion Embrittlement of Duralumin IV : The Use of Protective Coatings

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1928-01-01

    Although the corrosion resistance of sheet duralumin can be greatly improved by suitable heat treatment, protection of the surface is still necessary if long life under varied service conditions is to be insured. The coatings used for this purpose may be grouped into three classes: the varnish type of coating, the oxide type produced by a chemical treatment of the surface, and metallic coatings, of which aluminum appears to be the most promising. Since the necessary weather exposure tests are not complete, some of the conclusions regarding the value of various surface coatings are necessarily tentative.

  10. An Innovative Ceramic Corrosion Protection System for Zircaloy Cladding

    SciTech Connect

    Ronald H. Baney, Dr. D. Butt, Dr. P. Demkowicz, Dr. G. Fuchs Department of Materials Science; James S. Tulenko, Department of Nuclear and Radiological Engineering; University of Florida.

    2003-02-19

    Light Water reactor (LWR) fuel performance is currently limited by thermal, chemical and mechanical constraints associated with the design, fabrication, and operation of the fuel in incore operation. Corrosion of the zirconium based (Zircaloy-4) alloy cladding of the fuel is a primary limiting factor. Recent success at the University of Florida in developing thin ceramic films with great adhesive properties for metal substrates offers an innovative breakthrough for eliminating a major weakness of the Zircaloy clad. ?The University of Florida proposes to coat the existing Zircaloy clad tubes with a ceramic coating for corrosion protection. An added bonus of this approach would be the implementation of a boron-containing burnable poison outer layer will also be demonstrated as part of the ceramic coating development. In this proposed effort, emphasis will be on the ceramic coating with only demonstration of feasibility on the burnable outer coating approach. This proposed program i s expected to give a step change (approximately a doubling) in clad lifetime before failure due to corrosion. In the development of ceramic coatings for Zircaloy-4 clad, silicon carbide and zirconium carbide coatings will first be applied to Zircaloy-4 coupons and cladding samples by thermal assisted chemical vapor deposition, plasma assisted chemical vapor deposition or by laser ablation deposition. All of these processes are in use at the University of Florida and have shown great potential. The questions of adhesion and thermal expansion mismatch of the ceramic coating to the Zircaloy substrate will be addressed. Several solutions to these conditions will be examined, if needed. These solutions include the use of a zirconium oxide compliant layer, employment of a laser roughened surface and the use of a gradient composition interlayer. These solutions have already been shown to be effective for other high modulus coatings on metal substrates. Mechanical properties and adhesion of the

  11. High-temperature protection of steel goods from gas corrosion

    SciTech Connect

    Gerasimov, V.V.; Porfir`eva, R.T.; Peskov, A.V.

    1993-06-20

    The feasibility of using phosphorus-containing compounds to activate the thermal diffusion impregnation of steels with aluminum was explored and substantiated by experiment. Volatile phosphorus formed from the thermal destruction of the phosphorus-containing substances and the resulting Al/P-type complexes, which provide a gas-transportation medium to take the aluminum to the article surface, were instrumental in the mechanism. The resultant thermal diffusion coatings enabled steel to be safely protected from gas corrosion at a temperature of 950{degrees}C. As a result of research on the structure of the protective layer using electron microscopy and X-ray phase analysis, coatings formed using a mixture containing 1 wt.% iron glycerophosphate exhibited the optimum operating characteristics.

  12. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  13. Maintaining Corrosion Protection by Anticipating Increased Environment, Safety and Health Requirements

    DTIC Science & Technology

    2009-02-01

    4. TITLE AND SUBTITLE Maintaining Corrosion Protection by Anticipating Increased Environment, Safety and Health Requirements 5a. CONTRACT NUMBER 5b...responding? Environment, Safety and Health (ESH) Corrosion Prevention and Control (CPC) RDECOM  Often competing requirements  Many CPC...2001, Environmental Protection Agency: “highly likely” to be carcinogenic in humans  2006, National Research Council: “potential human carcinogen

  14. Recent Developments on Autonomous Corrosion Protection Through Encapsulation

    NASA Technical Reports Server (NTRS)

    Li, W.; Buhrow, J. W.; Calle, L. M.; Gillis, M.; Blanton, M.; Hanna, J.; Rawlins, J.

    2015-01-01

    This paper concerns recent progress in the development of a multifunctional smart coating, based on microencapsulation, for the autonomous detection and control of corrosion. Microencapsulation has been validated and optimized to incorporate desired corrosion control functionalities, such as early corrosion detection and inhibition, through corrosion-initiated release of corrosion indicators and inhibitors, as well as self-healing agent release triggered by mechanical damage. While proof-of-concept results have been previously reported, more recent research and development efforts have concentrated on improving coating compatibility and synthesis procedure scalability, with a targeted goal of obtaining easily dispersible pigment-grade type microencapsulated materials. The recent progress has resulted in the development of pH-sensitive microparticles as a corrosion-triggered delivery system for corrosion indicators and inhibitors. The synthesis and early corrosion indication results obtained with coating formulations that incorporate these microparticles are reported. The early corrosion indicating results were obtained with color changing and with fluorescent indicators.

  15. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

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

  16. Recent Developments on Microencapsulation for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Fitzpatrick, Lilliana; Jolley, Scott T.; Surma, Jan M.; Pearman, Benjamin P.; Zhang, Xuejun

    2014-01-01

    This work concerns recent progress in the development of a multifunctional smart coating based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of desired corrosion control functionalities, such as early corrosion detection and inhibition through corrosion controlled release of corrosion indicators and inhibitors, as well as self-healing agent release when mechanical damage occurs.While proof-of-concept results have been reported previously, more recent efforts have been concentrated in technical developments to improve coating compatibility, synthesis procedure scalability, as well as fine tuning the release property of encapsulated active agents.

  17. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... the prevention of atmospheric corrosion. (c) Except portions of pipelines in offshore splash zones...

  18. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... the prevention of atmospheric corrosion. (c) Except portions of pipelines in offshore splash zones...

  19. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... the prevention of atmospheric corrosion. (c) Except portions of pipelines in offshore splash zones...

  20. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... the prevention of atmospheric corrosion. (c) Except portions of pipelines in offshore splash zones...

  1. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... the prevention of atmospheric corrosion. (c) Except portions of pipelines in offshore splash zones...

  2. Protection of bronze artefacts through polymeric coatings based on nanocarriers filled with corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    de Luna, Martina Salzano; Buonocore, Giovanna; Di Carlo, Gabriella; Giuliani, Chiara; Ingo, Gabriel M.; Lavorgna, Marino

    2016-05-01

    Protective coatings based on polymers synthesized from renewable sources (chitosan or an amorphous vinyl alcohol based polymer) have been prepared for the protection of bronze artifacts from corrosion. Besides acting as an effective barrier against corrosive species present in the environment, the efficiency of the coatings has been improved by adding corrosion inhibitor compounds (benzotriazole or mercaptobenzothiazole) to the formulations. The liquid medium of the formulations has been carefully selected looking at maximizing the wettability on the bronze substrate and optimizing the solvent evaporation rate. The minimum amount of inhibitor compounds has been optimized by performing accelerated corrosion tests on coated bronze substrates. The inhibitors have been directly dissolved in the coating-forming solutions and/or introduced by means of nanocarriers, which allow to control the release kinetics. The free dissolved inhibitor molecules immediately provide a sufficient protection against corrosion. On the other hand, the inhibitor molecules contained in the nanocarriers serve as long-term reservoir, which can be activated by external corrosion-related stimuli in case of particularly severe conditions. Particular attention has been paid to other features which affect the coating performances. Specifically, the adhesion of the protective polymer layer to the bronze substrate has been assessed, as well as its permeability properties and transparency, the latter being a fundamental feature of protective coating for cultural heritages. Finally, the protective efficiency of the produced smart coatings has been assessed through accelerated corrosion tests.

  3. The Corrosion Protection of Magnesium Alloy AZ31B

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.; Mitchell, M. L.; Torres, P. D.

    1997-01-01

    Corrosion rates for bare and coated Magnesium alloy AZ31B have been measured. Two coatings, Dow-23(Trademark) and Tagnite(Trademark), have been tested by electrochemical methods and their effectiveness determined. Electrochemical methods employed were the scanning reference electrode technique (SRET), the polarization resistance technique (PR) and the electrochemical impedance spectroscopy technique (EIS). In addition, general corrosion and stress corrosion methods were employed to examine the effectiveness of the above coatings in 90 percent humidity. Results from these studies are presented.

  4. Marine corrosion protective coatings of hexagonal boron nitride thin films on stainless steel.

    PubMed

    Husain, Esam; Narayanan, Tharangattu N; Taha-Tijerina, Jose Jaime; Vinod, Soumya; Vajtai, Robert; Ajayan, Pulickel M

    2013-05-22

    Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings.

  5. Corrosion protection of steel in ammonia/water heat pumps

    DOEpatents

    Mansfeld, Florian B.; Sun, Zhaoli

    2003-10-14

    Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

  6. A Survey of Corrosion and Conditions of Corrosion Protection Systems in Civil Works Structures of the U.S. Army Corps of Engineers

    DTIC Science & Technology

    2014-09-01

    hydraulic steel structures ( HSS ) throughout its 45 districts. Many of these structures suffer from the adverse effects of cor- rosion. Efforts to minimize...maintenance are crucial elements of the corrosion protection systems that will allow continued safe use of HSS . Many of the Corps’ HSS are aged beyond...the condition of HSS within select Corps districts, their current corrosion protection systems, the degree to which corrosion monitoring and

  7. Corrosion Protection of Launch Infrastructure and Hardware Through the Space Shuttle Program

    NASA Technical Reports Server (NTRS)

    Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, has been a challenging and costly problem that has affected NASA's launch operations since the inception of the Space Program. Corrosion studies began at NASA's Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long-term protective coatings for the atmospheric protection of carbon steel. NASA's KSC Beachside Corrosion Test Site, which has been documented by the American Society of Materials (ASM) as one of the most corrosive, naturally occurring environments in the world, was established at that time. With the introduction of the Space Shuttle in 1981, the already highly corrosive natural conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocket boosters. In the years that followed, numerous efforts at KSC identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosiye environment at the launch pads. Knowledge on materials degradation, obtained by facing the highly corrosive conditions of the Space Shuttle launch environment, as well as limitations imposed by the environmental impact of corrosion control, have led researchers at NASA's Corrosion Technology Laboratory to establish a new technology development capability in the area of corrosion prevention, detection, and mitigation at KSC that is included as one of the "highest priority" technologies identified by NASA's integrated technology roadmap. A historical perspective highlighting the challenges encountered in protecting launch infrastructure and hardware from corrosion during the life of the Space Shuttle program and the new technological advances that have resulted from facing the unique and highly corrosive conditions of the Space Shuttle launch environment will be presented.

  8. Corrosion Protection of Al Alloys for Aircraft by Coatings With Advanced Properties and Enhanced Performance

    DTIC Science & Technology

    2007-12-20

    Sim6es, D. E. Tallman, G. P. Bierwagen, "Electrochemical Behaviour of a Mg-Rich Primer in the Protection of Al Alloys ," Corrosion Science 48 (2006...December 20, 200 Final Report July 1, 2004-June 30, 2007 4. TITLE AND SUBTITLE Sa. CONTRACT NUMBER Corrosion Protection of Al Alloys for Aircraft by...Prof. Dennis E. Tallman: A) New Scanning Probe Studies of Novel Cr-free Active Coatings B) Examination of the Influence of Surface Preparation of Al

  9. Synthesizing and Characterizing a Waterborne Polyaniline for Corrosion Protection of Steels

    NASA Astrophysics Data System (ADS)

    Pan, Tongyan; Yu, Qifeng; Miao, Tao

    2015-02-01

    This study explores the idea of synthesizing and characterizing a new intrinsically conducting polyaniline that at the molecular level carries a hydrophilic component, making the polymer highly waterborne and thereby applicable to massive production for corrosion protection of steels. The waterborne polyaniline was mixed in a water-based epoxy and then coated on SAE 1008/1010 steel samples for evaluating its anti-corrosion capacity using a powerful surface-analysis tool, Scanning Kelvin Probe Force Microscopy (SKPFM). The high resolution surface topography and corrosion potential of steel samples coated with the Polyaniline-based primer, as studied by SKPFM, show significantly lower corrosion activities than two control groups: uncoated steel samples and epoxy-only coated samples that were also subjected to SKPFM analyses under the same corrosive condition. The surface analysis results indicate that this new waterborne polyaniline is capable of protecting steels from corrosion when mixed in conventional water-based epoxies, opening the door to the development of an economical and long-life coating for corrosion protection of steel structures.

  10. Corrosion of connectors used in equipment protecting against falls from a height.

    PubMed

    Jachowicz, Marcin

    2015-01-01

    Connectors are commonly found in personal equipment protecting against falls from a height. They are typically used outdoors and exposed to atmospheric factors, which can result in corrosion. This article presents the results of a study involving exposure of connectors to experimental corrosive media - neutral salt spray (NSS), acid salt spray (ASS), and seawater mist (for elements made of carbon steel and non-ferrous metals) - and to experimental conditions simulating the processes of pitting, stress, and intercrystalline corrosion (for equipment made of s`tainless steel). The results indicate that the main effects of corrosion on connectors include impaired operation and reduced strength of their mobile elements. The article presents methods of testing connector operation developed for this purpose. Corrosive damage to connectors has been presented in relation to potential hazards for their users.

  11. Corrosion Protection of Al/Au/ZnO Anode for Hybrid Cell Application

    PubMed Central

    Slaughter, Gymama; Stevens, Brian

    2015-01-01

    Effective protection of power sources from corrosion is critical in the development of abiotic fuel cells, biofuel cells, hybrid cells and biobateries for implantable bioelectronics. Corrosion of these bioelectronic devices result in device inability to generate bioelectricity. In this paper Al/Au/ZnO was considered as a possible anodic substrate for the development of a hybrid cell. The protective abilities of corrosive resistant aluminum hydroxide and zinc phosphite composite films formed on the surface of Al/Au/ZnO anode in various electrolyte environments were examined by electrochemical methods. The presence of phosphate buffer and physiological saline (NaCl) buffer allows for the formation of aluminum hyrdroxide and zinc phosphite composite films on the surface of the Al/Au/ZnO anode that prevent further corrosion of the anode. The highly protective films formed on the Al/Au/ZnO anode during energy harvesting in a physiological saline environment resulted in 98.5% corrosion protective efficiency, thereby demonstrating that the formation of aluminum hydroxide and zinc phosphite composite films are effective in the prevention of anode corrosion during energy harvesting. A cell assembly consisting of the Al/Au/ZnO anode and platinum cathode resulted in an open circuit voltage of 1.03 V. A maximum power density of 955.3 μW/ cm2 in physiological saline buffer at a cell voltage and current density of 345 mV and 2.89 mA/ cm2, respectively. PMID:26580661

  12. Long-term corrosion protection by a thin nano-composite coating

    NASA Astrophysics Data System (ADS)

    Ejenstam, Lina; Tuominen, Mikko; Haapanen, Janne; Mäkelä, Jyrki M.; Pan, Jinshan; Swerin, Agne; Claesson, Per M.

    2015-12-01

    We report and discuss the corrosion protective properties of a thin nano-composite coating system consisting of an 11 μm thick polyester acrylate (PEA) basecoat, covered by an approximately 1-2 μm thick layer of TiO2 nanoparticles carrying a 0.05 μm thick hexamethyl disiloxane (HMDSO) top coat. The corrosion protective properties were evaluated on carbon steel substrates immersed in 3 wt% NaCl solution by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements. The protective properties of each layer, and of each pair of layers, were also evaluated to gain further understanding of the long-term protective properties offered by the nano-composite coating. The full coating system showed excellent corrosion protective properties in the corrosive environment of 3 wt% NaCl-solution for an extended period of 100 days, during which the coating impedance, at the lower frequency limit (0.01 Hz), remained above 108 Ω cm2. We suggest that the excellent corrosion protective properties of the complete coating system is due to a combination of (i) good adhesion and stability of the PEA basecoat, (ii) the surface roughness and the elongated diffusion path provided by the addition of TiO2 nanoparticles, and (iii) the low surface energy provided by the HMDSO top coat.

  13. The corrosion protection of 6061-T6 aluminum by a polyurethane-sealed anodized coat

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The corrosion protection of 6061-T6 anodized aluminum afforded by a newly patented polyurethane seal was studied using the ac impedance technique. Values of the average corrosion rates over a 27-day exposure period in 3.5 percent NaCl solutions at pH 5.2 and pH 9.5 compared very favorably for Lockheed-prepared polyurethane-sealed and dichromate-sealed coats of the same thickness. Average corrosion rates for both specimens over the first 7 days of exposure compared well with those for a hard anodized, dichromate-sealed coat, but rose well above those for the hard anodized coat over the entire 27-day period. This is attributed both to the greater thickness of the hard anodized coat, and possibly to its inherently better corrosion protective capability.

  14. Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

    NASA Technical Reports Server (NTRS)

    Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

    2002-01-01

    The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

  15. Corrosion resistant thermal barrier coating. [protecting gas turbines and other engine parts

    NASA Technical Reports Server (NTRS)

    Levine, S. R.; Miller, R. A.; Hodge, P. E. (Inventor)

    1981-01-01

    A thermal barrier coating system for protecting metal surfaces at high temperature in normally corrosive environments is described. The thermal barrier coating system includes a metal alloy bond coating, the alloy containing nickel, cobalt, iron, or a combination of these metals. The system further includes a corrosion resistant thermal barrier oxide coating containing at least one alkaline earth silicate. The preferred oxides are calcium silicate, barium silicate, magnesium silicate, or combinations of these silicates.

  16. High temperature corrosion-resistant protective coatings in stationary gas turbines

    NASA Technical Reports Server (NTRS)

    Gruenling, H. W.

    1977-01-01

    Methods currently used to deposit protective coatings in gas turbines are reviewed, and the structure of the respective coatings is examined. The corrosion behavior of such coatings is discussed on the basis of experimental data. General trends in the preparation of protective coatings are noted.

  17. REACH Compliant Hexavalent Chrome Replacement for Corrosion Protection (HITEA)

    DTIC Science & Technology

    2014-11-01

    members. Image courtesy of Manchester University Approved for distribution – Rolls Royce, 12/8/14 Report Documentation Page Form ApprovedOMB No. 0704...NUMBER OF PAGES 19 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298...is September 2017. 2 Engine Guide Vane Actuator Aluminium Housing •Forged / Make from Solid •Chromic acid anodised (CAA) externally. Aluminium Piston

  18. An alternate to chromate conversion coatings for the corrosion protection of aluminum 2024-T3

    NASA Astrophysics Data System (ADS)

    Guo, Ruiguang

    Corrosion of high-strength aluminum alloys used for airspace application is an expensive and serious problem. The most significant environmental factor contributing to the corrosion of these alloys is water condensed from humid air and contaminated with soluble chloride salts. The Al 2024 series used for aircraft are particularly susceptible to corrosion in aqueous chloride solutions due to alloying constituents such as copper and other impurities. Chromates are efficient inhibitors of corrosion of aluminum in near neutral aqueous environments containing aggressive anions such as chlorides. Usually, aluminum alloys are initially protected by chromate conversion coatings. Additional polymer coatings are sometimes added during exposure to corrosive atmospheres such as marine environments. Although chromate coatings are widely used, they require the use of noxious solutions, so they have always presented effluent disposal problems. There are health and safety concerns over the use of chromates due to their toxicity and carcinogenic nature and, as a consequence, the environmental and health risks associated with the use of such coatings will be restricted in the future. It was these health and safety concerns that led to the development of alternative non-toxic coating processes with comparable adhesion properties and corrosion protection. A variety of process technologies are under development and are vying for acceptance in industrial markets. As an alternate conversion coating, a new titanate conversion coating was systematically researched and developed. Research concentrated on producing passive surfaces from a simple titanate solution using an immersion process. The corrosion resistance of the treated surface has been evaluated using simple, rapid electrochemical techniques as well as a more long-term salt spray test. Passivation by titanate conversion treatment exhibits many similarities to chromate conversion treatment. Based on this study of corrosion

  19. A shape-recovery polymer coating for the corrosion protection of metallic surfaces.

    PubMed

    Lutz, Alexander; van den Berg, Otto; Van Damme, Jonas; Verheyen, Karen; Bauters, Erwin; De Graeve, Iris; Du Prez, Filip E; Terryn, Herman

    2015-01-14

    Self-healing polymer coatings are a type of smart material aimed for advanced corrosion protection of metals. This paper presents the synthesis and characterization of two new UV-cure self-healing coatings based on acrylated polycaprolactone polyurethanes. On a macroscopic scale, the cured films all show outstanding mechanical properties, combining relatively high Young's modulus of up to 270 MPa with a strain at break above 350%. After thermal activation the strained films recover up to 97% of their original length. Optical and electron microscopy reveals the self-healing properties of these coatings on hot dip galvanized steel with scratches and microindentations. The temperature-induced closing of such defects restores the corrosion protection and barrier properties of the coating as shown by electrochemical impedance spectroscopy and scanning vibrating electrode technique. Therefore, such coatings are a complementary option for encapsulation-based autonomous corrosion protection systems.

  20. Corrosion behavior of rebar for intermittent cathodic protection of coastal bridges

    SciTech Connect

    Ziomek-Moroz, M. | Cramer, S.D. | Covino, B.S., Jr. | Bullard, S.J. | Holcomb, G.R. | Russell, J.H. | Windisch, Jr., C.F.

    2001-02-01

    A number of reinforced concrete bridges on the Oregon coast are protected against chloride-induced corrosion damage by means of impressed current cathodic protection (ICCP). Thermal-sprayed Zn serves as the anode in these systems. Rebar in the concrete can remain passive and protected for some period of time after the CP system is turned off. The active-passive corrosion behavior of rebar in simulated pore solution (SPS) was investigated as a function of pH and Cl- concentration as part of a study of intermittent ICCP operation. Rebar corrosion rates in SPS were determined from polarization curves by fitting the Butler-Volmer equation and the linear polarization equation. Analysis of the passive film in SPS by x-ray diffraction and surface enhanced Raman spectroscopy showed it to be largely Fe3O4. However, the Fe(OH)2 content increased with cathodic polarization time.

  1. Structural and corrosion protection properties of electrochemically deposited nano-sized Zn-Ni alloy coatings

    NASA Astrophysics Data System (ADS)

    Tozar, A.; Karahan, İ. H.

    2014-11-01

    Zn-Ni alloy coatings were fabricated galvanostatically by applying varied current densities from 10 to 30 mA cm-2. Surface morphology of the coatings was examined with SEM. Crystal structure of the coatings was studied with X-ray diffraction spectroscopy (XRD). Compositions of the coatings were determined by atomic absorption spectroscopy (AAS). Corrosion protection properties studied using open circuit potential (OCP) measurements, potentiodynamic polarization measurements (Tafel), electrochemical impedance spectroscopy (EIS). Deposited alloy coatings were compact and nano-sized. Crystallite sizes of the coatings were varying from 26 nm to 36 nm. Nickel content of the samples were increased by increasing current densities and varied from 6.7 to 18.9 wt.%. Best corrosion protection performance was seen on the sample obtained at 30 mA cm-2. Our results are considerably encouraging for protection of mild steel against corrosion by obtained Zn-Ni alloys.

  2. Corrosion protected, multi-layer fuel cell interface

    DOEpatents

    Feigenbaum, Haim; Pudick, Sheldon; Wang, Chiu L.

    1986-01-01

    An improved interface configuration for use between adjacent elements of a fuel cell stack. The interface is impervious to gas and liquid and provides resistance to corrosion by the electrolyte of the fuel cell. The multi-layer configuration for the interface comprises a non-cupreous metal-coated metallic element to which is film-bonded a conductive layer by hot pressing a resin therebetween. The multi-layer arrangement provides bridging electrical contact.

  3. Embedded reference electrodes for corrosion potential monitoring, electrochemical characterization, and controlled-potential cathodic protection

    NASA Astrophysics Data System (ADS)

    Merten, Bobbi Jo Elizabeth

    A thin wire Ag/AgCl reference electrode was prepared using 50 mum Ag wire in dilute FeCl3. The wire was embedded beneath the polyurethane topcoat of two sacrificial coating systems to monitor their corrosion potential. This is the first report of a reference electrode embedded between organic coating layers to monitor substrate health. The embedded reference electrode (ERE) successfully monitored the corrosion potential of Mg primer on AA 2024-T3 for 800 days of constant immersion in dilute Harrison's solution. Zn primer on steel had low accuracy in comparison. This is in part due to short circuiting by Zn oxidation products, which are much more conductive than Mg corrosion products. Data interpretation was improved through statistical analysis. On average, ERE corrosion potentials are 0.1 to 0.2 V and 0.2 to 0.3 V more positive than a saturated calomel electrode (SCE) in solution for AA 2024-T3 and steel coating systems, respectively. Further research may confirm that ERE obtains corrosion potential information not possible by an exterior, conventional reference electrode. The ERE is stable under polarization. AA 2024-T3 was polarized to -0.95 V vs ERE to emulate controlled potential cathodic protection (CPCP) applications. Polarizations of -0.75 V vs ERE are recommended for future experiments to minimize cathodic delamination. The ERE was utilized to analyze coating mixtures of lithium carbonate, magnesium nitrate, and Mg metal on AA2024-T3. Corrosion potential, low frequency impedance by electrochemical impedance spectroscopy (EIS), and noise resistance by electrochemical noise method (ENM) were reported. Coating performance ranking is consistent with standard electrochemical characterization and visual analyses. The results suggest anti-corrosion resistance superior to a standard Mg primer following 1600 hours of B117 salt spray. Both lithium carbonate and magnesium nitrate are necessary to achieve corrosion protection. Unique corrosion protective coatings for

  4. Development of Spray Coating Methods and Materials to Replace Aluminum Cladding of Aging Aircraft for Corrosion Protection

    DTIC Science & Technology

    2007-06-01

    Replace FA9550-06-C-0113 Aluminum Cladding of Aging Aircraft for Corrosion Protection 5b. GRANTNUMBER [AF STTR Phase I Final Technical Report] 5c. PROGRAM...development of glassy coatings is limited by non-availability of aluminum based BMG powder feedstock for spraying. 15. SUBJECT TERMS STTR Report Corrosion ... aluminum cladding of aging aircraft for corrosion protection ABSTRACT The objective of this AF STTR Phase I work was to develop spray coating methods and new

  5. Nanoscale coatings for erosion and corrosion protection of copper microchannel coolers for high powered laser diodes

    NASA Astrophysics Data System (ADS)

    Flannery, Matthew; Fan, Angie; Desai, Tapan G.

    2014-03-01

    High powered laser diodes are used in a wide variety of applications ranging from telecommunications to industrial applications. Copper microchannel coolers (MCCs) utilizing high velocity, de-ionized water coolant are used to maintain diode temperatures in the recommended range to produce stable optical power output and control output wavelength. However, aggressive erosion and corrosion attack from the coolant limits the lifetime of the cooler to only 6 months of operation. Currently, gold plating is the industry standard for corrosion and erosion protection in MCCs. However, this technique cannot perform a pin-hole free coating and furthermore cannot uniformly cover the complex geometries of current MCCs involving small diameter primary and secondary channels. Advanced Cooling Technologies, Inc., presents a corrosion and erosion resistant coating (ANCERTM) applied by a vapor phase deposition process for enhanced protection of MCCs. To optimize the coating formation and thickness, coated copper samples were tested in 0.125% NaCl solution and high purity de-ionized (DIW) flow loop. The effects of DIW flow rates and qualities on erosion and corrosion of the ANCERTM coated samples were evaluated in long-term erosion and corrosion testing. The robustness of the coating was also evaluated in thermal cycles between 30°C - 75°C. After 1000 hours flow testing and 30 thermal cycles, the ANCERTM coated copper MCCs showed a corrosion rate 100 times lower than the gold plated ones and furthermore were barely affected by flow rates or temperatures thus demonstrating superior corrosion and erosion protection and long term reliability.

  6. Polyoxometalate ionic liquids as self-repairing acid-resistant corrosion protection.

    PubMed

    Herrmann, Sven; Kostrzewa, Monika; Wierschem, Andreas; Streb, Carsten

    2014-12-01

    Corrosion is a global problem for any metallic structure or material. Herein we show how metals can easily be protected against acid corrosion using hydrophobic polyoxometalate-based ionic liquids (POM-ILs). Copper metal disks were coated with room-temperature POM-ILs composed of transition-metal functionalized Keggin anions [SiW11 O39 TM(H2 O)](n-) (TM=Cu(II) , Fe(III) ) and quaternary alkylammonium cations (Cn H2 n+1 )4 N(+) (n=7-8). The corrosion resistance against acetic acid vapors and simulated "acid rain" was significantly improved compared with commercial ionic liquids or solid polyoxometalate coatings. Mechanical damage to the POM-IL coating is self-repaired in less than one minute with full retention of the acid protection properties. The coating can easily be removed and recovered by rinsing with organic solvents.

  7. Corrosion of Metal Films with Defective Surface Protection Layers.

    DTIC Science & Technology

    1980-07-01

    Evaporation 5 x I0- 100-150 25-35 S-Gun Sputtering 2 x 10-3 (argon) 6 35 was applied and patterned. Aqua regia was used to remove the platinum down to...Dielectric Layers Electrochemical Measurements Aluminum Thin Films Surface pH Measurements Gold Thin Films TRACT (Contfne o- reverse aide Hf nec.eary...between lines and line resis- tance were monitored at intervals. In one case, the potential was reversed after a certain time. Cathodic corrosion was

  8. Evaluation of Corrosion Protection Methods for Aluminum Metal Matrix Composites

    DTIC Science & Technology

    1992-08-01

    also appreciate the efforts of Professors Goo, Sadhal, 3Gershenzon, Langhon and Salovey who served on my Guidance and Dissertation 5 Committees. The...Shih, J. Electrochem. Soc., 135, 1171-1172 (1988). 176. S.E. Frers, M.M. Stefenel, C. Mayer and T. Chierchie, J. Appl. Electrochem., 20, 996-999 (1990...Keddam, Corrosion Science, 21 1-18 (1988). 94. J. Bessone, C. Mayer , K. Juttner and W.J. Lorenz, Electrochimica Acta, 28, 171-175 (1983). 3- 95. W

  9. Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

    NASA Astrophysics Data System (ADS)

    Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

    2015-12-01

    The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

  10. A polyaniline based intrinsically conducting coating for corrosion protection of structural steels.

    PubMed

    Pan, Tongyan; Wang, Zhaoyang

    2013-11-01

    Among the various corrosion protection strategies for structural steels, coating techniques provide the most cost-effective protection and have been used as the primary mode of corrosion protection. Existing coating techniques however have been used mainly for their barrier capability and therefore all have a limited service life due to oxidation aging, electrolytic degradation, or various inadvertent defects and flaws occurred in and after coating applications. This work investigated the anti-corrosion potential of a π-conjugated polymer-polyaniline (PANi), which was doped into an intrinsically conducting polymer and then included in a two-layer coating system as a primer layer. To achieve a long service life, the primer layer was made by mixing the conductive PANi in a waterborne poly-vinyl butyral solution to provide strong adhesion to steel surface, and then topcoated with a layer of elastomer-modified polyethylene to obtain extra mechanical and barrier protections. Two ASTM standard tests were conducted to evaluate the corrosion durability and tensile adhesion of the two-layer system, in which the system demonstrated superior performance. The Scanning Kelvin Probe Force Microscopy (SKPFM) was used to provide the microscopic evidences for the outstanding performance.

  11. Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection

    DTIC Science & Technology

    2009-02-01

    Carbon Nanotube Functionalization /Doping Polyvinylpyrrolidone (PVP) A) p-Doping C) Polymer Wrapping Model B) n-Doping Polyethyleneimine ( PEI ) SWCNT Paint...fluorine-containing) groups functions as the barrier layer Multilayer Smart Carbon Nanotube Coating Insoluble polymer layer top coating -PMMA Substrate...Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection Zafar Iqbal Department of Chemistry and Environmental Science New

  12. Electrochemical investigation of powder coatings and their application to magnesium-rich primers for corrosion protection

    NASA Astrophysics Data System (ADS)

    Orgon, Casey Roy

    Corrosion is the decomposition of metal and metal alloys which threatens the integrity of man-made structures. One of the more efficient methods of delaying the corrosion process in metals is by coatings. In this work, the durability of two polyester powder coatings were investigated for corrosion protection of AA-2024-T3. Polyester powder coatings crosslinked by either triglycidyl isocyanurate (TGIC) or beta-hydroxyalkyl amide (HAA) compounds were prepared and investigated for barrier protection of metal substrates by electrochemical impedance spectroscopy (EIS). Polyester-TGIC coatings were found to provide better long-term protection, which can be attributed to the increased mechanical strength and higher concentration of crosslinking in the coating films. Additionally, the polyester powder coatings, along with a fusion bonded epoxy (FBE) were investigated for their compatibility as a topcoat for magnesium-rich primers (MgRP). Under proper application conditions, powder topcoats were successfully applied to cured MgRP while corrosion protection mechanisms of each system were maintained.

  13. Porous 'Ouzo-effect' silica-ceria composite colloids and their application to aluminium corrosion protection.

    PubMed

    Hollamby, Martin J; Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry

    2012-01-04

    By exploiting spontaneous emulsification to prepare porous SiO(2) particles, we report the formation of porous CeO(2)@SiO(2) hybrid colloids and their incorporation into a silica-zirconia coating to improve the corrosion protection of aluminium.

  14. TiO2 membranes for concurrent photocatalytic organic degradation and corrosion protection

    NASA Astrophysics Data System (ADS)

    Liang, Robert; Hatat-Fraile, Melisa; He, Horatio; Arlos, Maricor; Servos, Mark R.; Zhou, Y. Norman

    2015-10-01

    Organic contaminants and corrosion in water treatment effluents are a current global problem and the development of effective methods to facilitate the removal of organic contaminants and corrosion control strategies are required to mitigate this problem. TiO2 nanomaterials that are exposed to UV light can generate electron-hole pairs, which undergo redox reactions to produce hydroxyl radicals from adsorbed molecular oxygen. They hydroxyl radicals are able to oxidize organic contaminants in water. This same process can be used in conjunction to protect metals from corrosion via cathodic polarization. In this work, TiO2 nanomaterials were synthesized and electrophoretically deposited on conductive substrates to serve as films or membranes. An illuminated TiO2 film on a conductive surface served as the photoanode and assisted in the cathodic protection of stainless steel (SS304) and the degradation of organic pollutants, in this case glucose. This proof-of-concept relied on photoelectrochemical experiments conducted using a potentiostat and a xenon lamp illumination source. The open-circuit potential changes that determine whether a metal is protected from corrosion under illumination was observed; and the electrical characteristics of the TiO2 film or membrane under dark and arc lamp illumination conditions were also analyzed. Furthermore, the effect of organic contaminants on the photocathodic protection mechanism and the oxidation of glucose during this process were explored.

  15. Civil Engineering Corrosion Control. Volume 3. Cathodic Protection Design

    DTIC Science & Technology

    1975-02-01

    and wind -d’iven genera- tors have been used. 2 CRITERIA FOR PROTECTION. Different methods and cr1- teria are available to determine effectiveness of...lower current for adequatei 1protection. This is a basic part of cathodic protection, greatly reducing operating costs . In acid environments...Thermoelectric generatorBattery4 Generator - driven by eng .e, wind , or fluid turbine Direct current - from power used mainly by other equipment Solar cell

  16. Silica mesoporous thin films as containers for benzotriazole for corrosion protection of 2024 aluminium alloys

    NASA Astrophysics Data System (ADS)

    Recloux, Isaline; Mouanga, Maixent; Druart, Marie-Eve; Paint, Yoann; Olivier, Marie-Georges

    2015-08-01

    This work contributes to the development of a new environmentally friendly alternative pretreatment for 2024 aluminium alloys to replace hexavalent chromium based conversion layers in the aeronautical field. A silica mesoporous thin film, synthesized through the evaporation induced self-assembly process, was doped with benzotriazole to obtain active corrosion protection. Inhibitor loading contents were correlated with pore characteristics. The release kinetics was studied as function of pH. The application of the doped mesoporous film on 2024 aluminium alloy revealed a slowing down of corrosion processes, demonstrating its potential as an active inhibitor storage layer.

  17. Protection of 2024-T3 aluminium alloy by corrosion resistant phytic acid conversion coating

    NASA Astrophysics Data System (ADS)

    Shi, Hongwei; Han, En-Hou; Liu, Fuchun; Kallip, Silvar

    2013-09-01

    The corrosion protection properties of environmentally friendly phytic acid conversion coatings were studied on 2024-T3 aluminium alloy. The films were prepared under acidic conditions with various pH values and characterised by SEM, EDS, ATR-FTIR and electrochemical techniques. The results indicate that the conversion coatings obtained by immersing the alloy in phytic acid solutions at pH from 3 to 5.5 provide excellent corrosion resistance. ATR-FTIR confirms that the film is formed by deposition of reaction products between Al3+ and phosphate groups in phytic acid molecules. The conformation models of the deposition film are proposed.

  18. 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.

  19. Enhancement of active corrosion protection via combination of inhibitor-loaded nanocontainers.

    PubMed

    Tedim, J; Poznyak, S K; Kuznetsova, A; Raps, D; Hack, T; Zheludkevich, M L; Ferreira, M G S

    2010-05-01

    The present work reports the synthesis of layered double hydroxides (LDHs) nanocontainers loaded with different corrosion inhibitors (vanadate, phosphate, and 2-mercaptobenzothiazolate) and the characterization of the resulting pigments by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The anticorrosion activity of these nanocontainers with respect to aluminum alloy AA2024 was investigated by electrochemical impedance spectroscopy (EIS). The bare metallic substrates were immersed in dispersions of nanocontainers in sodium chloride solution and tested to understand the inhibition mechanisms and efficiency. The nanocontainers were also incorporated into commercial coatings used for aeronautical applications to study the active corrosion protection properties in systems of industrial relevance. The results show that an enhancement of the active protection effect can be reached when nanocontainers loaded with different inhibitors are combined in the same protective coating system.

  20. Peptide-based biocoatings for corrosion protection of stainless steel biomaterial in a chloride solution.

    PubMed

    Muruve, Noah G G; Cheng, Y Frank; Feng, Yuanchao; Liu, Tao; Muruve, Daniel A; Hassett, Daniel J; Irvin, Randall T

    2016-11-01

    In this work, PEGylated D-amino acid K122-4 peptide (D-K122-4-PEG), derived from the type IV pilin of Pseudomonas aeruginosa, coated on 304 stainless steel was investigated for its corrosion resistant properties in a sodium chloride solution by various electrochemical measurements, surface characterization and molecular dynamics simulation. As a comparison, stainless steel electrodes coated with non-PEGylated D-amino acid retroinverso peptide (RI-K122-4) and D-amino acid K122-4 peptide (D-K122-4) were used as control variables during electrochemical tests. It was found that the D-K122-4-PEG coating is able to protect the stainless steel from corrosion in the solution. The RI-K122-4 coating shows corrosion resistant property and should be investigated further, while the D-K122-4 peptide coating, in contrast, shows little to no effect on corrosion. The morphological characterizations support the corrosion resistance of D-K122-4-PEG on stainless steel. The adsorption of D-K122-4 molecules occurs preferentially on Fe2O3, rather than Cr2O3, present on the stainless steel surface.

  1. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    NASA Astrophysics Data System (ADS)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2015-01-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  2. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    NASA Astrophysics Data System (ADS)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2014-09-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  3. Electric power plants: protective coatings and corrosion inhibition. January, 1966-September, 1981 (citations from the Metals Abstracts data base). Report for Jan 66-Sep 81

    SciTech Connect

    Not Available

    1981-09-01

    Protective coatings for power plants are discussed. Corrosion protection by means of applied coatings or the use of electrochemical inhibition is featured. Particular emphasis is placed on the effects of corrosion on the strength of materials used in various types of power plants, and includes stress corrosion cracking and erosion protection. The effects of cyclic loading and thermal expansion of heat exchanger tubes on corrosion are also included. (Contains 162 citations fully indexed and including a title list.)

  4. Corrosion control acceptance criteria for sacrificial anode type, cathodic protection systems (user guide)

    NASA Astrophysics Data System (ADS)

    Hock, Vincent F.; Noble, Michael; McLeod, Malcolm E.

    1994-07-01

    The Army currently operates and maintains more than 20,000 underground storage tanks and over 3000 miles of underground gas pipelines, all of which require some form of corrosion control. Cathodic protection is one method of corrosion control used to prevent corrosion-induced leaks when a steel structure is exposed to an aggressive soil. The corrosion control acceptance criteria for sacrificial anode type CP systems provides guidelines for the DEH/DPW cathodic protection installation inspectors whose responsibilities are to ensure that the materials and equipment specified are delivered to the job site and subsequently installed in accordance with the engineering drawings and specifications. The sacrificial anode CP acceptance criteria includes all components for the sacrificial anode system such as insulated conductors, anodes, anode backfills, and auxiliary equipment. The sacrificial anode CP acceptance criteria is composed of a checklist that lists each component and that contains a space for the inspector to either check 'yes' or 'no' to indicate whether the component complies with the job specifications. In some cases, the inspector must measure and record physical dimensions or electrical output and compare the measurements to standards shown in attached tables.

  5. An electrochemical evaluation of new materials and methods for corrosion protection

    NASA Astrophysics Data System (ADS)

    Kus, Esra

    An electrochemical evaluation of various electrode/electrolyte systems was performed by means of electrochemical impedance spectroscopy (EIS) and other techniques. Each chapter in this thesis presents an individual project with a specific objective which serves an ultimate goal of finding better materials and methods of corrosion protection. An overview of new environmentally friendly and cost effective materials and corrosion protection methods is given in Chapter 1. The protective properties of non-toxic, environmentally friendly polymer coatings, which were developed in the purpose of minimizing biofouling and providing corrosion protection on steel, were investigated and discussed in Chapter 2. The corrosion resistance of steel panels coated with crosslinked siloxanes was evaluated using EIS. Differences in protective properties of the coatings were observed due to differences in the degree of fluorination, the way the films were cured and also the degree of crosslinking. In Chapter 3, a comparison of the corrosion behavior of nanocrystalline (NC) Al 5083 with that of the conventional alloy was made in order to determine what differences if any could be attributed to the NC microstructure. Pit growth rates decreased with time for both materials based on the analysis of the impedance spectra as a function of time. NC samples were resistant to intergranular corrosion whereas conventional Al 5083 was not. The concept of the bacterial battery is presented in Chapter 4. A galvanic cell with Cu and Al 2024 and an electrolyte containing Shewanella oneidensis MR-1 in a growth medium was prepared. A control cell, which did not contain the bacteria, was also tested. For the cell with MR-1 the maximum power values increased continuously with time, whereas in the control cell the maximum power output was obtained in the first day of exposure. The objective of the study presented in Chapter 5 was to examine the interaction of MR-1 with different metal surfaces in order to

  6. Positron annihilation behavior in several corrosion protective polymeric coatings

    NASA Astrophysics Data System (ADS)

    Leidheiser, Henry; Szeles, Csaba; Vértes, Attila

    1987-04-01

    Positron annihilation was studied in a vinyl ester and four epoxy coatings on steel. Measurements were made on coatings in equilibrium with air at approximately 50% relative humidity and on coatings immersed in liquid water for 24 h. Three spectral components were identified: a short-lived component associated with annihilation largely in the steel substrate; a medium-lived component associated with annihilation in small voids in the coating; and a long-lived component associated with annihilation of o-positronium in the polymer matrix and within large voids in the polymer and at the polymer/metal interface. An excellent correlation was observed between the effect of water exposure on the annihilation spectra and the protective properties of the coating in an aggressive H 2SO 4 environment. Other correlations between the annihilation spectra and the protective properties were also identified.

  7. Corrosion Protection Properties of PPy-ND Composite Coating: Sonoelectrochemical Synthesis and Design of Experiment

    NASA Astrophysics Data System (ADS)

    Ashassi-Sorkhabi, H.; Bagheri, R.; Rezaei-Moghadam, B.

    2016-02-01

    In this research, the nanocomposite coatings comprising the polypyrrole-nanodiamond, PPy-ND, on St-12 steel electrodes were electro-synthesized using in situ polymerization process under ultrasonic irradiation. The corrosion protection performance and morphology characterization of prepared coatings were investigated by electrochemical methods and scanning electron microscopy, SEM, respectively. Also, the experimental design was employed to determine the best values considering the effective parameters such as the concentration of nanoparticles, the applied current density and synthesis time to achieve the most protective films. A response surface methodology, RSM, involving a central composite design, CCD, was applied to the modeling and optimization of the PPy-ND nanocomposite deposition. Pareto graphic analysis of the parameters indicated that the applied current density and some of the interactions were effective on the response. The electrochemical results proved that the embedment of diamond nanoparticle, DNP, improves the corrosion resistance of PPy coatings significantly. Therefore, desirable correlation exists between predicted data and experimental results.

  8. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    Prof. Stratis V. Sotirchos

    2001-02-01

    The main objective of this research project was the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Since alumina has excellent resistance to corrosion but coefficient than silicon carbide, the key idea of this project has been to develop graded coatings with composition varying smoothly along their thickness between an inner (base) layer of mullite in contact with the silicon carbide component and an outer layer of pure alumina, which would function as the actual protective coating of the component. (Mullite presents very good adhesion towards silicon carbide and has thermal expansion coefficient very close to that of the latter.)

  9. Inhibited ethylene and propylene glycols for corrosion and freeze protection in water-based HVAC systems

    SciTech Connect

    Roo, A.M. de; Lee, B.W.

    1997-12-31

    Industrially inhibited ethylene and propylene glycols are used extensively to provide protection against equipment damage due to corrosion and freezing. This paper will describe the proper use of these glycols, including system preparation, fluid installation, and fluid maintenance. The impact of the use of these glycols on the operation of the system is discussed along with methods for overcoming any declines in heat transfer. From this discussion, it will become clear why automotive antifreeze formulations should not be used in heating, ventilating, and airconditioning (HVAC) systems. Also included are data on the physical properties of aqueous solutions of ethylene and propylene glycol, the concept of burst vs. freeze protection, typical results of corrosion tests, and methods to use to monitor the fluid for each application.

  10. Weldability of Fe-Al-Cr Overlay Coatings for CorrosionProtection in Oxidizing/Sulfidizing Environments

    SciTech Connect

    Regina, JR

    2003-03-04

    The effect of chromium additions to the weldability of Fe-Al based overlay claddings are currently being investigated for the corrosion protection of boiler tubes in Low NOx furnaces. The primary objective of this research is to identify weldable (crack-free) Fe-Al-Cr weld overlay coating compositions that provide corrosion resistance over long exposure times. During the current project phase, preliminary corrosion testing was conducted on several ternary Fe-Al-Cr alloys in two types of gaseous corrosion environments. These long-term corrosion tests were used to develop a target weld composition matrix and serve as a base line for future corrosion tests. Preliminary Fe-Al based welds with various aluminum concentrations and one ternary Fe-Al-Cr weld overlay were successfully deposited using a Gas Tungsten Arc Welding (GTAW) process and cracking susceptibility was evaluated on these coatings.

  11. Aircraft surface coatings reduce drag, may protect against corrosion

    SciTech Connect

    Kreitinger, R.L.; Middleton, D.B.

    1982-02-01

    The aerodynamic drag on an airplane is a very important design parameter. However, after exposure to the environment and accidental spills the surface of the airplane may become corroded or erode; thus the drag may change. Researchers at Boeing Commercial Airplane Co. and the NASA-Langley Research Center have been studying the possibility of using smooth surface coatings to help reduce drag and protect the surface of the airplane. Elastomeric polyurethanes on portions of a test airplane have reduced total drag by 0.2% (as compared to a bare surface) at cruise Reynolds number.

  12. Assessment of the factors affecting protective alumina formation under hot corrosion conditions

    NASA Astrophysics Data System (ADS)

    Task, Michael Nathan

    In this study, the influence of microstructure, composition, and phase constitution on the Type I (900°C) and Type II (700°C) hot corrosion resistance of MCrAlY and β-NiAl base alloys was investigated. The Type II hot corrosion resistance of MCrAlY alloys is generally enhanced by microstructural refinement. This can be attributed to the more rapid establishment of a protective Al2O3-rich scale due to the higher density of short-circuit diffusion paths for Al (phase boundaries). However, it was shown that for a given bulk composition, the compositions of the individual phases is also extremely important. If one phase is lean in an element which is highly beneficial from a hot corrosion standpoint, e.g., Cr, Type II hot corrosion resistance is quite poor, regardless of the microstructural scale. In addition, coarse reactive-element-rich phases, which are commonly found in MCrAlY alloys, can be incorporated into the thermally grown Al2O 3 scale and act as initiation sites for Type II attack. This stresses the importance of reactive element content and distribution in MCrAlY coatings. During Type I hot corrosion exposure of β-Ni-36Al (at. %) base alloys, the incubation stage is greatly extended by the addition of 5% Pt, Co, or Cr. In each case, the beneficial effects can be linked to an enhanced ability to rapidly form a protective Al2O3 scale, and to heal this scale when it sustains damage during exposure. With regard to Type II hot corrosion, individual additions of 5 at. % Pt or Cr are beneficial, largely for the same reason; however, additions of 5 at. % Co and co-additions of 5 at. % Pt + 5 at. % Cr result in a decrease in the duration of the incubation stage. Subsurface phase transformations that occur in the latter systems prevent the alloy from maintaining the growth of the Al2O3 scale. This mechanism is discussed in detail. Finally, the influence of alloy composition and exposure environment on the kinetics of the θ→α Al2O3 transformation in scales

  13. Synthesis and corrosion protection properties of poly(o-phenylenediamine) nanofibers.

    PubMed

    Muthirulan, P; Kannan, N; Meenakshisundaram, M

    2013-07-01

    The present study shows a novel method for the synthesis of uniformly-shaped poly(othophenylediamine) (PoPD) nanofibers by chemical oxidative polymerization method for application towards smart corrosion resistance coatings. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) studies confirm morphology of PoPD with three dimensional (3D) networked dendritic superstructures having average diameter of 50-70 nm and several hundred meters of length. UV-vis and FTIR spectral results shows the formation of PoPD nanofibers containing phenazine ring ladder-structure with benzenoid and quinoid imine units. Thermogravimetric analyses (TGA) of PoPD nanofibers possess good thermal stability. The anti-corrosion behavior of PoPD nanofibers on 316L SS was investigated in 3.5% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements. The PoPD coated 316L SS exhibits higher corrosion potential when compared to uncoated specimen. EIS studies, clearly ascertain that PoPD nanofiber coatings exhibits excellent potential barrier to protect the 316L SS against corrosion in 3.5% NaCl.

  14. Large area laser surface treatment of aluminium alloys for pitting corrosion protection

    NASA Astrophysics Data System (ADS)

    Chong, P. H.; Liu, Z.; Skeldon, P.; Thompson, G. E.

    2003-03-01

    Laser surface treatment has been recognised as a useful method for corrosion protection of surfaces as a result of improved microstructure/phase formation and compositions. In large area applications, overlapping of individual tracks corresponding to the width of the laser beam is often necessary. This involves re-melting and re-heating of a portion of the previous track and results in microstructural changes, such as precipitate coarsening and microsegregation, which may influence localised corrosion at the overlapped regions. The purpose of this work is to investigate the influence of overlapped regions on corrosion behaviour of laser-melted aluminium 2014-T6 alloy. Laser melting was carried out using a 3 kW CW Nd:YAG laser with a line beam profile. The microstructures of the central part and the overlapped region of the melt pool were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Pitting corrosion resistance was evaluated using potentiodynamic anodic polarisation in 1 M NaCl solution. The work revealed enhancement of the pitting potential by 170 mV compared with that of the untreated alloy, similar to that achieved by laser surface melting with a CO 2 laser in a Gaussian mode. The line beam profile results in elimination of the planar front zones at the treated surface, but this benefit was offset by a coarser microstructure.

  15. Hybrid organic-inorganic coatings including nanocontainers for corrosion protection of magnesium alloy ZK30

    NASA Astrophysics Data System (ADS)

    Kartsonakis, I. A.; Koumoulos, E. P.; Charitidis, C. A.; Kordas, G.

    2013-08-01

    This study is focused on the fabrication, characterization, and application of corrosion protective coatings to magnesium alloy ZK30. Hybrid organic-inorganic coatings were synthesized using organic-modified silicates together with resins based on bisphenol A diglycidyl ether. Cerium molybdate nanocontainers (ncs) with diameter 100 ± 20 nm were loaded with corrosion inhibitor 2-mercaptobenzothiazole and incorporated into the coatings in order to improve their anticorrosion properties. The coatings were investigated for their anticorrosion and nanomechanical properties. The morphology of the coatings was examined by scanning electron microscopy. The composition was estimated by energy-dispersive X-ray analysis. The mechanical integrity of the coatings was studied through nanoindentation and nanoscratch techniques. Scanning probe microscope imaging of the coatings revealed that the addition of ncs creates surface incongruity; however, the hardness to modulus ratio revealed significant strengthening of the coating with increase of ncs. Studies on their corrosion behavior in 0.5 M sodium chloride solutions at room temperature were made using electrochemical impedance spectroscopy. Artificial defects were formatted on the surface of the films in order for possible self-healing effects to be evaluated. The results showed that the coated magnesium alloys exhibited only capacitive response after exposure to corrosive environment for 16 months. This behavior denotes that the coatings have enhanced barrier properties and act as an insulator. Finally, the scratched coatings revealed a partial recovery due to the increase of charge-transfer resistance as the immersion time elapsed.

  16. Synthesis and corrosion protection properties of poly(o-phenylenediamine) nanofibers

    PubMed Central

    Muthirulan, P.; Kannan, N.; Meenakshisundaram, M.

    2012-01-01

    The present study shows a novel method for the synthesis of uniformly-shaped poly(othophenylediamine) (PoPD) nanofibers by chemical oxidative polymerization method for application towards smart corrosion resistance coatings. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) studies confirm morphology of PoPD with three dimensional (3D) networked dendritic superstructures having average diameter of 50–70 nm and several hundred meters of length. UV–vis and FTIR spectral results shows the formation of PoPD nanofibers containing phenazine ring ladder-structure with benzenoid and quinoid imine units. Thermogravimetric analyses (TGA) of PoPD nanofibers possess good thermal stability. The anti-corrosion behavior of PoPD nanofibers on 316L SS was investigated in 3.5% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements. The PoPD coated 316L SS exhibits higher corrosion potential when compared to uncoated specimen. EIS studies, clearly ascertain that PoPD nanofiber coatings exhibits excellent potential barrier to protect the 316L SS against corrosion in 3.5% NaCl. PMID:25685444

  17. Electrochemical synthesis and characterisation of hybrid materials polypyrrole/dodecatungstophosphate as protective agents against steel corrosion

    NASA Astrophysics Data System (ADS)

    Bonastre Cano, Jose Antonio

    The losses caused by the effect of the corrosion are of the order of 2-3,5% of the GDP of the developed countries or developing only in direct costs, losses in structures or products. This figure doubles by the indirect costs, losses of productivity or demands for delays. Beside the possible losses of human lives, any intent leaded to the decrease of the corrosion in rusty metals is a commendable objective from the point of view of the protection of the environment. Building industry employing reinforced concrete is able to project some structural elements (pillars, wrought, beam, etc.) in principle free of corrosion, assuring during many years the useful life of the work in service. However, the reinforced concrete would be' a perfect solution if the indefinite permanency of the passive state of the steel could be guaranteed. Indeed, although the steel is protected against corrosion due to basic pH which provides the cement, the severe action of saline media or the effect of CO2 can diminish this protection conditions beginning the corrosion in steel elements. Type-p doped conducting polymers, as polypyrrole, are firm candidates to protect carbon steel providing galvanic protection by stabilising the passive layer of Fe oxides initially grown. Doping the polymeric matrix with polioxometalates, concretely phosphotungstate PW12O403-, is a very interesting hypothesis due to their oxidising effect, improving the anodic protection by the hybrid material electrosynthesised on carbon steel substrate. First in the present work, a new method was developed by cyclic voltammetry in LiClO4 + acetonitrile medium in order to diminish the unavoidable oxidation of carbon steel when the electrosyntesis of the hybrid material polypyrrole/PW12O403- is carrying out. The beginning potential of polypyrrole polymerisation is about 0.8 V (vs. Ag/AgCl), a positive potential where oxidation of Fe substrate is high, not allowing the electrodeposition of the hybrid material. On the other

  18. Comparison of some corrosion-protective coatings for inner surfaces of tanks

    SciTech Connect

    Mityagin, V.A.; Vigant, G.T.; Zakharova, N.N.

    1995-07-01

    Zinc-filled, sprayed-zinc, epoxy, and vinyl chloride coatings were comparatively studied as applied to corrosion protection of inner surfaces and tanks for clarified petroleum products. Tests were carried out by cycles of temperature variation from 60{degrees}C to - 25{degrees}C, on steel plates in vapor, in fuel, and in electrolyte, simulating sub-product water. The coatings KhS-5132, KhS-717 (vinyl chloride) and BEP-68, EP-525, EP-0010 (epoxy) are of the highest protective properties, resistant to steaming and washing with aqueous solutions of synthetic detergents, and are compatible with clarified petroleum products.

  19. Self-immunity microcapsules for corrosion protection of steel bar in reinforced concrete

    NASA Astrophysics Data System (ADS)

    Wang, Yanshuai; Fang, Guohao; Ding, Weijian; Han, Ningxu; Xing, Feng; Dong, Biqin

    2015-12-01

    A novel microcapsule-based self-immunity system for reinforced concrete is proposed. Its feasibility for hindering the corrosion of steel rebar by means of lifting the threshold value of [Cl-]/[OH-] is discussed. Precisely controlled release behavior enables corrosion protection in the case of depassivation. The release process is characterized over a designated range of pH values, and its release characteristics of the microcapsules, triggered by decreasing pH value, are captured by observing that the core crystals are released when exposed to a signal (stimulus). The aim of corrosion protection of steel bar is achieved through the constantly-stabilized passive film, and its stability is promoted using continuous calcium hydroxide released from the microcapsule, restoring alkaline conditions. The test results exhibited that the release process of the microcapsules is a function of time. Moreover, the release rate of core materials could interact with environmental pH value, in which the release rate is found to increase remarkably with decreasing pH value, but is inhibited by high pH levels.

  20. Self-immunity microcapsules for corrosion protection of steel bar in reinforced concrete.

    PubMed

    Wang, Yanshuai; Fang, Guohao; Ding, Weijian; Han, Ningxu; Xing, Feng; Dong, Biqin

    2015-12-17

    A novel microcapsule-based self-immunity system for reinforced concrete is proposed. Its feasibility for hindering the corrosion of steel rebar by means of lifting the threshold value of [Cl(-)]/[OH(-)] is discussed. Precisely controlled release behavior enables corrosion protection in the case of depassivation. The release process is characterized over a designated range of pH values, and its release characteristics of the microcapsules, triggered by decreasing pH value, are captured by observing that the core crystals are released when exposed to a signal (stimulus). The aim of corrosion protection of steel bar is achieved through the constantly-stabilized passive film, and its stability is promoted using continuous calcium hydroxide released from the microcapsule, restoring alkaline conditions. The test results exhibited that the release process of the microcapsules is a function of time. Moreover, the release rate of core materials could interact with environmental pH value, in which the release rate is found to increase remarkably with decreasing pH value, but is inhibited by high pH levels.

  1. Self-immunity microcapsules for corrosion protection of steel bar in reinforced concrete

    PubMed Central

    Wang, Yanshuai; Fang, Guohao; Ding, Weijian; Han, Ningxu; Xing, Feng; Dong, Biqin

    2015-01-01

    A novel microcapsule-based self-immunity system for reinforced concrete is proposed. Its feasibility for hindering the corrosion of steel rebar by means of lifting the threshold value of [Cl−]/[OH−] is discussed. Precisely controlled release behavior enables corrosion protection in the case of depassivation. The release process is characterized over a designated range of pH values, and its release characteristics of the microcapsules, triggered by decreasing pH value, are captured by observing that the core crystals are released when exposed to a signal (stimulus). The aim of corrosion protection of steel bar is achieved through the constantly-stabilized passive film, and its stability is promoted using continuous calcium hydroxide released from the microcapsule, restoring alkaline conditions. The test results exhibited that the release process of the microcapsules is a function of time. Moreover, the release rate of core materials could interact with environmental pH value, in which the release rate is found to increase remarkably with decreasing pH value, but is inhibited by high pH levels. PMID:26673425

  2. Slippery liquid-infused porous surface based on perfluorinated lubricant/iron tetradecanoate: Preparation and corrosion protection application

    NASA Astrophysics Data System (ADS)

    Yang, Shengsheng; Qiu, Ri; Song, Hongqing; Wang, Peng; Shi, Zhiqiang; Wang, Yanfang

    2015-02-01

    Corrosion and fouling have been two major enemies for materials immersed in seawater. Fluid including gas and liquid as coating for marine corrosion protection has attracted much attention, since it can also exert antifouling capability in seawater environment. Combining gas and solid phases, superhydrophobic surface is promising to protect the underlying metal from corrosion. However, the intrinsically short sustainability in underwater environment has hindered its practical application, so that its corrosion protection ability is only temporary. Originated from liquid and solid phases, slippery liquid-infused porous surface (SLIPS) has spurred wide interest due to its prominent performance in different fields. However, the exploration of corrosion protection efficiency from SLIPS remains rare. In this research, SLIPS is constructed onto steel surface via a facile two-step protocol. First, based on a dissolution-deposition strategy, iron tetradecanoate is formed by an electrochemical route. After that, fluid lubricant is infused onto the deposit, whose rough surface acts as the reservoir to entrap the fluid to form a static liquid coating. Compared to the bare and hydrophobic deposit covering low alloy steel, the SLIPS composed perfluorinated lubricant and iron tetradecanoate endows good corrosion protection property.

  3. Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid

    NASA Astrophysics Data System (ADS)

    Ramya, K.; Mohan, Revathi; Joseph, Abraham

    2014-11-01

    Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (Δ E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 Å. This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.

  4. Corrosion protection performance of porous strontium hydroxyapatite coating on polypyrrole coated 316L stainless steel.

    PubMed

    Gopi, D; Ramya, S; Rajeswari, D; Kavitha, L

    2013-07-01

    Polypyrrole/strontium hydroxyapatite bilayer coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium hydroxyapatite. The formation and the morphology of the bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium hydroxyapatite layer can provide potential bioactivity to the 316L SS.

  5. Conducting polyaniline nanoparticles and their dispersion for waterborne corrosion protection coatings.

    PubMed

    Chen, Fei; Liu, Peng

    2011-07-01

    A novel approach for preparing waterborne corrosion protection polyaniline (PANI)-containing coatings was developed. First, conducting polyaniline/partially phosphorylated poly(vinyl alcohol) (PANI/P-PVA) spherical nanoparticles with significant dispersibility in aqueous media were prepared by the chemical oxidative dispersion polymerization in presence of partially phosphorylated poly(vinyl alcohol) (P-PVA). The PANI/P-PVA-containing coatings with different PANI/P-PVA contents were then prepared, employing waterborne epoxy resin as the matrix. The corrosion protection property of PANI/P-PVA-containing coatings on mild steel was investigated by salt spray test and electrochemical impedance spectroscopy (EIS) technique in 3.0 wt % NaCl aqueous solution. The results indicated that the waterborne PANI/P-PVA-containing coatings (PANI/P-PVA content, 2.5 wt %) could offer high protection because the impedance values remained at higher than 1 × 10(7) Ω cm(2) after 30 days of salt spray tests. All the results were compared with these of the waterborne coatings containing PANI nanoparticles in the emeraldine salt form (PANI ES), and the protection mechanism was also proposed with the evidence of scanning electron microscope (SEM) and X-ray photoelectron spectrometry (XPS).

  6. Development of nanostructured coatings for protecting the surface of aluminum alloys against corrosion and ice accretion

    NASA Astrophysics Data System (ADS)

    Farhadi, Shahram

    Ice and wet snow accretion on outdoor structures is a severe challenge for cold climate countries. A variety of de-icing and anti-icing techniques have been developed so far to counter this problem. Passive approaches such as anti-icing or icephobic coatings that inhibit or retard ice accumulation on the surfaces are gaining in popularity. Metal corrosion should also be taken into account as metallic substrates are subject to corrosion problems when placed in humid or aggressive environments. Development of any ice-releasing coatings on aluminum structures, as they must be durable enough, is therefore closely related to anti-corrosive protection of that metal. Accordingly, series of experiments have been carried out to combine reduced ice adhesion and improved corrosion resistance on flat AA2024 substrates via thin films of single and double layer alkyl-terminated SAMs coatings. More precisely, alkyl-terminated aluminum substrates were prepared by depositing layer(s) of 18C-SAMs on BTSE-grafted AA2024 or mirror-polished AA2024 surfaces. This alloy is among the most widely used aluminum alloys in transportation systems (including aircraft), the military, etc. The stability of the coatings in an aggressive environment, their overall ice-repellent performance as well as their corrosion resistance was systematically studied. The stability of one-layer and two-layer coatings in different media was tested by means of CA measurements, demonstrating gradual loss of the hydrophobic property after ~1100-h-long immersion in water, associated by decrease in water CA. Surface corrosion was observed in all cases, except that the double-layer coating system provided improved anti-corrosive protection. All single layer coatings showed initial shear stress of ice detachment values of ~1.68 to 2 times lower than as-received aluminum surfaces and about ~1.22 to 1.5 times lower than those observed on mirror-polished surfaces. These values gradually increased after as many as 5 to 9

  7. Corrosion protection of Arctic offshore structures: Final report. [Effects of temperature and salinity on required cathodic protection current

    SciTech Connect

    Sackinger, W.M.; Rogers, J.C.; Feyk, C.; Theuveny, B.

    1985-10-01

    Results are presented for a research program on corrosion prevention for Arctic offshore structures which are in contact with sea ice for a significant portion of the year. The electrical method most adaptable for structure protection involves the injection of impressed current from several remote anodes buried just beneath the sea floor. The electrical resistivity of annual sea ice as a function of temperature and salinity is presented. Details of the interface layers formed between sea ice and steel in the presence of current injection are shown. A computer program was developed to enable the calculation of protective current density into the structure, in the presence of ice rubble and ridges around the structure. The program and the results of an example calculation are given for a caisson- retained island structure. 81 refs., 103 figs., 3 tabs.

  8. The corrosion protection of 2219-T87 aluminum by organic and inorganic zinc-rich primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

    1995-01-01

    The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electro-chemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. the galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 micro A/cm(exp 2) and 23.7 micro A/cm(exp 2) for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

  9. Studies on adhesion characteristics and corrosion behaviour of vinyltriethoxysilane/epoxy coating protective system on aluminium

    NASA Astrophysics Data System (ADS)

    Bajat, Jelena B.; Milošev, Ingrid; Jovanović, Željka; Mišković-Stanković, Vesna B.

    2010-03-01

    The corrosion stability of vinyltriethoxysilane/epoxy coating protective system on aluminium is strongly related to the strength of bonds forming at the metal/organic coating interface. This article is a study of adhesion, composition, electrochemical and transport properties of epoxy coatings electrodeposited on bare aluminium and aluminium pretreated by vinyltriethoxysilane (VTES) during exposure to 3% NaCl. The VTES film was deposited on aluminium surface from 2% vinyltriethoxysilane solution during 30 s. From the values of adhesion strength (pull-off test), time dependence of pore resistance and coating capacitance of epoxy coating (impedance measurements) and diffusion coefficient of water through epoxy coating (gravimetric liquid sorption measurements), the influence of VTES sublayer on the corrosion stability of the electrodeposited epoxy coating was shown. The work discusses the role of the VTES pretreatment in the enhanced adhesion and corrosion stability of epoxy cataphoretic coating. The electrochemical results showed that the aluminium pretreatment by VTES film improved barrier properties of epoxy coating (greater pore resistance and lower coating capacitance). The lower value of diffusion coefficient of water through epoxy coating indicates the lower porosity, while the smaller adhesion reduction points to better adhesion of epoxy coating on aluminium pretreated by VTES film. The composition of the deposited coatings investigated by XPS enabled the clarification of the bonding mechanism.

  10. Corrosion protection of SiC-based ceramics with CVD mullite coatings

    SciTech Connect

    Sarin, V.; Mulpuri, R.; Auger, M.

    1996-04-20

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can withstand the rigorous requirements imposed by such applications. Chemical vapor deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and good coefficient of thermal expansion match with SiC are being developed as a potential solution. Formation of mullite on ceramic substrates via chemical vapor deposition was investigated. Thermodynamic calculations performed on the AlCl{sub 3}- SiCl{sub 4}-CO{sub 2}-H{sub 2} system were used to construct equilibrium CVD phase diagrams. Through process optimization, crystalline CVD mullite coatings have been successfully grown on SiC and Si{sub 3}N{sub 4} substrates. Results from the thermodynamic analysis, process optimization, and effect of various process parameters on deposition rate and coating morphology are discussed.

  11. Protection of copper surface with phytic acid against corrosion in chloride solution.

    PubMed

    Peca, Dunja; Pihlar, Boris; Ingrid, Milošev

    2014-01-01

    Phytic acid (inositol hexaphosphate) was tested as a corrosion inhibitor for copper in 3% sodium chloride. Phytic acid is a natural compound derived from plants, it is not toxic and can be considered as a green inhibitor. Electrochemical methods of linear polarization and potentiodynamic polarization were used to study the electrochemical behaviour and evaluate the inhibition effectiveness. To obtain the optimal corrosion protection the following experimental conditions were investigated: effect of surface pre-treatment (abrasion and three procedures of surface roughening), pre-formation of the layer of phytic acid, time of immersion and concentration of phytic acid. To evaluate the surface pre-treatment procedures the surface roughness and contact angle were measured. Optimal conditions for formation of phytic layer were selected resulting in the inhibition effectiveness of nearly 80%. Morphology and composition of the layer were further studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The layer of phytic acid with thickness in the nanometer range homogeneously covers the copper surface. The obtained results show that this natural compound can be used as a mildly effective corrosion inhibitor for copper in chloride solution.

  12. The Corrosion Protection of 2219-T87 Aluminum by Organic and Inorganic Zinc-Rich Primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

    1995-01-01

    The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 pA/CM2 and 23.7 pA/CM2 for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

  13. Development of self-healing coatings for corrosion protection on metallic structures

    NASA Astrophysics Data System (ADS)

    Stankiewicz, Alicja; Barker, Michael B.

    2016-08-01

    Inspired by biological systems, artificial self-healing materials are designed for repairing local damage caused by external factors. The rapidly expanding field of self-healing systems contains, among others, materials with well-defined surface properties. Undoubtedly, enhancing surface functionalisation, by applying smart coatings, enjoys an extensive interest. The self-healing ability is particularly essential property for corrosion protection strategies, especially when the use of one of the most effective corrosion systems, based on chromium(VI) compounds, is now banned by the current registration, evaluation, authorisation and restriction of chemicals legislation. Self-healing protective coatings are produced using macromolecular compounds, ceramics, metals and composites. Considering the wide range of available materials, the number of potential combinations seems to be unlimited. The self-healing action of such coatings is activated by appropriate stimuli: temperature changes, radiation, pH changes, pressure changes and mechanical action. In this paper, the research and practical implications of the various approaches to achieving self-healing functionality of protective coatings, as well as potential developments in this area, are explored.

  14. Preparation of γ-Mercaptopropyltrimethoxysilane's Films to Protect Steel Against Corrosion

    NASA Astrophysics Data System (ADS)

    Deyá, Cecilia

    2015-03-01

    Traditionally, chromates and phosphates were used as pretreatments for metals to protect them from corrosion during a temporary period. Nowadays, due to their toxicity, replacements are being study. The most studied compounds are based on silanes and, among them, glicidoxypropyltrimethoxysilane, aminopropyltrimethoxysilane, and mercaptopropyltrimethoxysilane are the most important ones. The objective of this research work was to study the anticorrosive protection afforded by films of γ-mercaptopropyltrimethoxysilane deposited on SAE 1010 steel in order to select the optimum preparation conditions. The films were applied on sandblasted steel after 24 or 48 h of hydrolysis of the silane in a water/methanol solution (1.5/1, by volume) and cured for 10 min at 80 °C or for 1 h at 100 °C. In order to evaluate the characteristics of the films, Fourier transformed infrared spectroscopy was done on the films and the coated surfaces were observed by scanning electron microscopy. The anticorrosive protection afforded by the films was studied by electrochemical tests employing polarization curves (Tafel mode) in 0.5 M NaCl solution and corrosion potential measurements in NaCl 0.05 M. The best results were obtained with silane hydrolyzed for 48 h cured at 80 °C for 10 min.

  15. Comparative Behaviour of Nitrite and Nitrate for the Protection of Rebar Corrosion

    NASA Astrophysics Data System (ADS)

    Ahmad, Altaf; Kumar, Anil

    2016-10-01

    Corrosion of rebar steel due to environmental causes has been studied through various approaches, and among the protection techniques use of inhibitors has gained encouragement. Nitrites and nitrates of sodium have gained sufficient scientific coverage. Recently, nitrites and nitrates of calcium have been verified in some studies, which, however, needs further experimentation through different angles. Simple polarization technique has been utilized in the present study to compare inhibitive efficiency of these salts of sodium and calcium, which indicate that calcium salts are more efficient.

  16. The role of surface preparation in corrosion protection of copper with nanometer-thick ALD alumina coatings

    NASA Astrophysics Data System (ADS)

    Mirhashemihaghighi, Shadi; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Klein, Lorena H.; Salmi, Emma; Ritala, Mikko; Marcus, Philippe

    2016-11-01

    Surface smoothening by substrate annealing was studied as a pre-treatment for improving the corrosion protection provided to copper by 10, 20 and 50 nm thick alumina coatings deposited by atomic layer deposition. The interplay between substrate surface state and deposited film thickness for controlling the corrosion protection provided by ultrathin barrier films is demonstrated. Pre-annealing at 750 °C heals out the dispersed surface heterogeneities left by electropolishing and reduces the surface roughness to less than 2 nm independently of the deposited film thickness. For 10 nm coatings, substrate surface smoothening promotes the corrosion resistance. However, for 20 and 50 nm coatings, it is detrimental to the corrosion protection due to local detachment of the deposited films. The weaker adherence of the thicker coatings is assigned to the stresses accumulated in the films with increasing deposited thickness. Healing out the local heterogeneities on the substrate surface diminishes the interfacial strength that is bearing the stresses of the deposited films, thereby increasing adhesion failure for the thicker films. Pitting corrosion occurs at the local sites of adhesion failure. Intergranular corrosion occurs at the initially well coated substrate grain boundaries because of the growth of a more defective and permeable coating at grain boundaries.

  17. Indium oxide thin film as potential photoanodes for corrosion protection of stainless steel under visible light

    SciTech Connect

    Zhang, Yan; Yu, Jianqiang; Sun, Kai; Zhu, Yukun; Bu, Yuyu; Chen, Zhuoyuan

    2014-05-01

    Graphical abstract: If the conduction band potential of In{sub 2}O{sub 3} is more negative than the corrosion potential of stainless steel, photo-induced electrons will be transferred from In{sub 2}O{sub 3} to the steel, thus shifting the potential of the steel into a corrosion immunity region and preventing the steel from the corrosion. - Highlights: • Indium oxide performed novel application under visible light. • Indium oxide by sol–gel method behaved better photoelectrochemical properties. • Electrons were transferred to stainless steel from indium oxide once light on. - Abstract: This paper reports the photoelectrochemical cathodic protection of 304 stainless steel by In{sub 2}O{sub 3} thin-film under visible-light. The films were fabricated with In{sub 2}O{sub 3} powders, synthesized by both sol–gel (In{sub 2}O{sub 3}-sg) and solid-state (In{sub 2}O{sub 3}-ss) processes. The photo-induced open circuit potential and the photo-to-current efficiency measurements suggested that In{sub 2}O{sub 3} could be a promising candidate material for photoelectrochemical cathodic protection of metallic alloys under visible light. Moreover, the polarization curve experimental results indicated that In{sub 2}O{sub 3}-sg thin-film can mitigate the corrosion potential of 304 stainless steel to much more negative values with a higher photocurrent density than the In{sub 2}O{sub 3}-ss film under visible-light illumination. All the results demonstrated that the In{sub 2}O{sub 3}-sg thin-film provides a better photoelectrochemical cathodic protection for 304 stainless steel than In{sub 2}O{sub 3}-ss thin-film under visible-light illumination. The higher photoelectrochemical efficiency is possibly due to the uniform thin films produced with the smaller particle size of In{sub 2}O{sub 3}-sg, which facilitates the transfer of the photo-induced electrons from bulk to the surface and suppresses the charge recombination of the electrons and holes.

  18. Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel.

    PubMed

    Del Frari, D; Bour, J; Bardon, J; Buchheit, O; Arnoult, C; Ruch, D

    2010-04-01

    Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers.

  19. Atomic Layer Deposited Coatings on Nanowires for High Temperature Water Corrosion Protection.

    PubMed

    Yersak, Alexander S; Lewis, Ryan J; Liew, Li-Anne; Wen, Rongfu; Yang, Ronggui; Lee, Yung-Cheng

    2016-11-30

    Two-phase liquid-cooling technologies incorporating micro/nanostructured copper or silicon surfaces have been established as a promising thermal management solution to keep up with the increasing power demands of high power electronics. However, the reliability of nanometer-scale features of copper and silicon in these devices has not been well investigated. In this work, accelerated corrosion testing reveals that copper nanowires are not immune to corrosion in deaerated pure hot water. To solve this problem, we investigate atomic layer deposition (ALD) TiO2 coatings grown at 150 and 175 °C. We measured no difference in coating thickness for a duration of 12 days. Using a core/shell approach, we grow ALD TiO2/Al2O3 protective coatings on copper nanowires and demonstrate a preservation of nanoengineered copper features. These studies have identified a critical reliability problem of nanoscale copper and silicon surfaces in deaerated, pure, hot water and have successfully demonstrated a reliable solution using ALD TiO2/Al2O3 protective coatings.

  20. Waterborne chitosan-epoxysilane hybrid pretreatments for corrosion protection of zinc.

    PubMed

    Fernández-Solis, Christian; Erbe, Andreas

    2016-06-23

    Biopolymer-based systems are extensively studied as green alternatives for traditional polymer coatings, e.g., in corrosion protection. Chitosan-epoxysilane hybrid films are presented in this work as a chitosan-based protective system, which could, e.g., be applied in a pretreatment step. For the preparation of the chitosan-epoxysilane hybrid systems, a sol-gel procedure was applied. The function of the silane is to ensure adhesion to the substrate. On zinc substrates, homogeneous thin films with thickness of 50-70 nm were obtained after thermal curing. The hybrid-coated zinc substrates were characterized by infrared spectroscopy, ellipsometry, and x-ray photoelectron spectroscopy. As model corrosion experiments, linear polarization resistance was measured, and cathodic delamination of the weak polymer coating poly(vinylbutyral) (PVB) was studied using scanning Kelvin probe. Overall, chitosan-epoxysilane hybrid pretreated samples showed lower delamination rates than unmodified chitosan coatings and pure PVB. Electrochemical impedance spectroscopy confirmed a reduced ion permeability and water uptake by chitosan-epoxysilane films compared to that of a nonmodified chitosan coating. Even though the coatings are hydrophobic and contain water, they slow down cathodic delamination by limiting ion transport.

  1. Electrochemical synthesis of polypyrrole-Al2O3 composite coating on 316 stainless steel for corrosion protection

    NASA Astrophysics Data System (ADS)

    Yan, Qun; Li, Chuanxian; Huang, Tingting; Yang, Fei

    2017-03-01

    Polypyrrole (PPy)-Al2O3 composite coating was electrochemically deposited on 316 stainless steel (316 SS) by cyclic voltammetry technique. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were employed to understand the morphology and composition of the PPy-Al2O3 coated SS. The corrosion protection ability of the PPy-Al2O3 coating was studied using open circuit potential (Eocp)-time measurements, polarization curves, and electrochemical impedance spectroscopy (EIS) after the electrodes had been immersed in a 3.5 wt% NaCl solution as the corrosive media. The results showed that PPy-Al2O3 composite coatings have a homogeneous and smooth surface without detectable cracks. Anodic polarization analysis revealed that the hybrid films provided an exceptional barrier and corrosion protection in comparison with PPy coating. The EIS studies indicated that the charge transfer resistance increases with the presence of PPy-Al2O3. PPy-Al2O3 composite coating provides better corrosion protection and can be considered as a coating material to protect 316SS. With increase in Al2O3/Py mole ratio, PPy-Al2O3 coatings tend to exhibit a better corrosion resistance ability.

  2. Replacement of corrosion protection chromate primers and paints used in cryogenic applications on the Space Shuttle with wire arc sprayed aluminum coatings

    NASA Technical Reports Server (NTRS)

    Daniel, R. L.; Sanders, H. L.; Zimmerman, F. R.

    1995-01-01

    With the advent of new environmental laws restricting volatile organic compounds and hexavalent chrome emissions, 'environmentally safe' thermal spray coatings are being developed to replace the traditional corrosion protection chromate primers. A wire arc sprayed aluminum coating is being developed for corrosion protection of low pressure liquid hydrogen carrying ducts on the Space Shuttle Main Engine. Currently, this hardware utilizes a chromate primer to provide protection against corrosion pitting and stress corrosion cracking induced by the cryogenic operating environment. The wire are sprayed aluminum coating has been found to have good potential to provide corrosion protection for flight hardware in cryogenic applications. The coating development, adhesion test, corrosion test and cryogenic flexibility test results will be presented.

  3. Smart epoxy coating containing Ce-MCM-22 zeolites for corrosion protection of Mg-Li alloy

    NASA Astrophysics Data System (ADS)

    Wang, Yanli; Zhu, Yanhao; Li, Chao; Song, Dalei; Zhang, Tao; Zheng, Xinran; Yan, Yongde; Zhang, Meng; Wang, Jun; Shchukin, Dmitry G.

    2016-04-01

    The epoxy coatings containing MCM-22 and Ce-MCM-22 zeolites were prepared by coating method on the Mg-Li alloy surface. The influence of MCM-22 and Ce-MCM-22 zeolites on corrosion protection of the epoxy coating was studied. The epoxy coating containing Ce-MCM-22 zeolites showed high corrosion resistance. Artificial defects in the epoxy coating containing Ce-MCM-22 zeolites on the Mg-Li surface were produced by the needle punching. The results show that the epoxy coating containing Ce-MCM-22 zeolites exhibits self-healing corrosion inhibition capabilities. It is ascribed to the fact that the Ce3+ ions are released from MCM-22 zeolites based on ion exchange of zeolite in the corrosion process of the Mg-Li alloy substrate. MCM-22 zeolites as reservoirs provided a prolonged release of cerium ions.

  4. Refractory Materials for Flame Deflector Protection System Corrosion Control: Flame Deflector Protection System Life Cycle Cost Analysis Report

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Coffman, Brekke E.; Kolody, Mark R.; Curran, Jerome P.; Trejo, David; Reinschmidt, Ken; Kim, Hyung-Jin

    2009-01-01

    A 20-year life cycle cost analysis was performed to compare the operational life cycle cost, processing/turnaround timelines, and operations manpower inspection/repair/refurbishment requirements for corrosion protection of the Kennedy Space Center launch pad flame deflector associated with the existing cast-in-place materials and a newer advanced refractory ceramic material. The analysis compared the estimated costs of(1) continuing to use of the current refractory material without any changes; (2) completely reconstructing the flame trench using the current refractory material; and (3) completely reconstructing the flame trench with a new high-performance refractory material. Cost estimates were based on an analysis of the amount of damage that occurs after each launch and an estimate of the average repair cost. Alternative 3 was found to save $32M compared to alternative 1 and $17M compared to alternative 2 over a 20-year life cycle.

  5. Electric power plants: protective coatings and corrosion inhibition. January, 1970-September, 1981 (citations from the Engineering Index data base). Report for Jan 70-Sep 81

    SciTech Connect

    Not Available

    1981-09-01

    Protective coatings for power plants are discussed. Corrosion protection by means of applied coatings or the use of electrochemical inhibition is featured. Particular emphasis is placed on heat transfer problems associated with the formation of boiler scale on heat exchanger surfaces. Boiler water treatment for the inhibition of corrosion and the formation of deposits are also included, as is the removal of sulfur compounds to reduce high temperature sulfidation corrosion. (Contains 134 citations fully indexed and including a title list.)

  6. Corrosion protection of high-copper aluminum alloys using green technology

    SciTech Connect

    Mansfeld, F.; Wang, Y.

    1995-09-01

    The concept of surface modification as a new method of corrosion protection using chemicals without toxic problems is described for the Al alloys Al 6061, Al 7075-T6 and Al 2024-T3. In the Ce-Mo process Ce and Mo are incorporated into the original oxide film by chemical and electrochemical processes. The resulting surfaces are resistant to pitting in aggressive solutions such as 0.5 N NaCl. Surface modified Al 6013 has passed the salt spray test according to ASTM B 117. For Al 6061 and 7075, hot solutions of CeCl{sub 3} and Ce(NO{sub 3}){sub 3} are used, while for Al 2024 CeCl{sub 3} is replaced by Ce acetate. For all alloys anodic polarization is carried out in Na{sub 2}MoO{sub 4}. For Al 2024 and Al 7075 a Cu removal pre-treatment step is used in which Cu intermetallic compounds are removed from the outer surface layers. The resistance to localized corrosion has been evaluated by recording of impedance spectra in 0.5 N NaCl for 30 days. Surface analysis data suggest that Ce and Mo are concentrated at sites where local cathodes such as Cu intermetallic compounds are located. Polarization curves show that both the cathodic and the anodic reaction are inhibited on modified surfaces. The pitting potential E{sub pit} is increased for surface modified samples at constant corrosion potential E{sub corr}. This result could be due to a decrease of the amount of Cl adsorbed at a given potential for oxide layers containing Ce and Mo.

  7. Atmospheric corrosion of Cu, Zn, and Cu-Zn alloys protected by self-assembled monolayers of alkanethiols

    NASA Astrophysics Data System (ADS)

    Hosseinpour, Saman; Forslund, Mattias; Johnson, C. Magnus; Pan, Jinshan; Leygraf, Christofer

    2016-06-01

    In this article results from earlier studies have been compiled in order to compare the protection efficiency of self-assembled monolayers (SAM) of alkanethiols for copper, zinc, and copper-zinc alloys exposed to accelerated indoor atmospheric corrosion conditions. The results are based on a combination of surface spectroscopy and microscopy techniques. The protection efficiency of investigated SAMs increases with chain length which is attributed to transport hindrance of the corrosion stimulators in the atmospheric environment, water, oxygen and formic acid, towards the copper surface. The transport hindrance is selective and results in different corrosion products on bare and on protected copper. Initially the molecular structure of SAMs on copper is well ordered, but the ordering is reduced with exposure time. Octadecanethiol (ODT), the longest alkanethiol investigated, protects copper significantly better than zinc, which may be attributed to the higher bond strength of Cu-S than of Zn-S. Despite these differences, the corrosion protection efficiency of ODT for the single phase Cu20Zn brass alloy is equally efficient as for copper, but significantly less for the heterogeneous double phase Cu40Zn brass alloy.

  8. Ceramic coatings of LA141 alloy formed by plasma electrolytic oxidation for corrosion protection.

    PubMed

    Li, Zhijun; Yuan, Yi; Sun, Pengpeng; Jing, Xiaoyan

    2011-09-01

    Superlight Mg-Li alloy is a promising structural materials in aerospace, automobile, and electronics because of its excellent properties such as low density, high ductility, superior strength-to-weight ratio, and good damping ability. The fabrication of compact plasma electrolytic oxidation coatings with excellent corrosion resistance is valuable for the widespread application of Mg-Li alloy. Here we present a ceramic coating on the surface of Mg-14Li-1Al (LA141) alloy for corrosion protection via plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte with tungstate as an additive. X-ray photoelectron spectroscopy and thin film-X-ray diffraction analysis of coatings show that the surface coating is mainly comprised of Mg(2)SiO(4), MgO and WO(3). Scanning electron microscopy observations have revealed that the dense and compact coating formed in the presence of tungstate has less structural imperfections in comparison to the control one fabricated without use of tungstate. The effect of oxidation time on the morphology and phase composition of coatings is also examined in detail.

  9. Plasma Sprayed Bondable Stainless Surface (BOSS) Coatings for Corrosion Protection and Adhesion Treatments

    NASA Technical Reports Server (NTRS)

    Davis, G. D.; Groff, G. B.; Rooney, M.; Cooke, A. V.; Boothe, R.

    1995-01-01

    Plasma-sprayed Bondable Stainless Surface (BOSS) coatings are being developed under the Solid Propulsion Integrity Program's (SPIP) Bondlines Package. These coatings are designed as a steel case preparation treatment prior to insulation lay-up. Other uses include the exterior of steel cases and bonding surfaces of nozzle components. They provide excellent bondability - rubber insulation and epoxy bonds fail cohesively within the polymer - for both fresh surfaces and surfaces having undergone natural and accelerated environmental aging. They have passed the MSFC requirements for protection of inland and sea coast environment. Because BOSS coatings are inherently corrosion resistant, they do not require preservation by greases or oils. The reduction/elimination of greases and oils, known bondline degraders, can increase SRM reliability, decrease costs by reducing the number of process steps, and decrease environmental pollution by reducing the amount of methyl chloroform used for degreasing and thus reduce release of the ozone-depleting chemical in accordance with the Clean Air Act and the Montreal Protocol. The coatings can potential extend the life of RSRM case segments and nozzle components by eliminating erosion due to multiple grit blasting during each use cycle and corrosion damage during marine recovery. Concurrent work for the Air Force show that other BOSS coatings give excellent bondline strength and durability for high-performance structures of aluminum and titanium.

  10. Silver deposition on polypyrrole films electrosynthesised onto Nitinol alloy. Corrosion protection and antibacterial activity.

    PubMed

    Saugo, M; Flamini, D O; Brugnoni, L I; Saidman, S B

    2015-11-01

    The electrosynthesis of polypyrrole films onto Nitinol from sodium salicylate solutions of different concentrations is reported. The morphology and corrosion protection properties of the resulting coatings were examined and they both depend on the sodium salicylate concentration. The immobilisation of silver species in PPy films constituted by hollow rectangular microtubes was studied as a function of the polymer oxidation degree. The highest amount of silver was deposited when the coated electrode was prepolarised at -1.00V (SCE) before silver deposition, suggesting an increase in the amount of non-oxidised segments in the polymer. Finally, the antibacterial activity of the coating against the Gram positive Staphylococcus aureus and Staphylococcus epidermidis bacteria was evaluated. Both strains resulted sensitive to the modified coatings, obtaining a slightly better result against S. aureus.

  11. Corrosion Protection Performance of Nano-SiO2/Epoxy Composite Coatings in Acidic Desulfurized Flue Gas Condensates

    NASA Astrophysics Data System (ADS)

    Wang, Z. B.; Wang, Z. Y.; Hu, H. X.; Liu, C. B.; Zheng, Y. G.

    2016-09-01

    Five kinds of nano-SiO2/epoxy composite coatings were prepared on mild steels, and their corrosion protection performance was evaluated at room temperature (RT) and 50 °C (HT) using electrochemical methods combined with scanning electron microscopy (SEM). The effects of preparation and sealing processes on the corrosion protection performance of epoxy coatings were specially focused on. The results showed that it was favorable for the corrosion protection and durable performance to add the modified nano-SiO2 during rather than after the synthesis of epoxy coatings. Furthermore, the employment of sealer varnish also had beneficial effects. The two better coatings still exhibited higher impedance values even after immersion tests for up to 1000 h at RT and 500 h at HT. SEM revealed that the improvement of corrosion protection performance mainly resulted from the enhancement of coating density. Moreover, the evolution of electrochemical behavior of the two better coatings with immersion time was also discussed by means of fitting the electrochemical impedance spectroscopy results using equivalent circuits with different physical meanings.

  12. Remote switch actuator

    DOEpatents

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan

    2013-01-29

    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  13. Corrosion: ASM metals handbook

    SciTech Connect

    Not Available

    1987-01-01

    The handbook covers forms of corrosion, testing and evaluation, corrosion-resistant design, and various protection methods. 20 sections covering specific metals and alloys, heat treatments, protective coatings, anodic and cathodic protection, and design considerations. A final section discusses corrosion problems in 20 major industries, as well as the prevention and protection methods used.

  14. Robust Slippery Coating with Superior Corrosion Resistance and Anti-Icing Performance for AZ31B Mg Alloy Protection.

    PubMed

    Zhang, Jialei; Gu, Changdong; Tu, Jiangping

    2017-03-29

    Biomimetic slippery liquid-infused porous surfaces (SLIPSs) are developed as a potential alternative to superhydrophobic surfaces (SHSs) to resolve the issues of poor durability in corrosion protection and susceptibility to frosting. Herein, we fabricated a double-layered SLIPS coating on the AZ31 Mg alloy for corrosion protection and anti-icing application. The porous top layer was infused by lubricant, and the compact underlayer was utilized as a corrosion barrier. The water-repellent SLIPS coating exhibits a small sliding angle and durable corrosion resistance compared with the SHS coating. Moreover, the SLIPS coating delivers durable anti-icing performance for the Mg alloy substrate, which is obviously superior to the SHS coating. Multiple barriers in the SLIPS coating, including the infused water-repellent lubricant, the self-assembled monolayers coated porous top layer, and the compact layered double hydroxide-carbonate composite underlayer, are suggested as being responsible for the enhanced corrosion resistance and anti-icing performance. The robust double-layered SLIPS coating should be of great importance to expanding the potential applications of light metals and their alloys.

  15. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, 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 coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  16. Current and potential distributions in corrosion systems

    SciTech Connect

    Smyrl, W.H.

    1980-01-01

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

  17. Practical Implications of the Use of Aluminide Coatings for the Corrosion Protection of Superalloys in Gas Turbines

    DTIC Science & Technology

    1984-04-01

    Strategic Materials Usage. Practical Implications of the Use of Aluminide Coatings for the Corrosion Protection of Superalloys in Gas Turbines. Coatings ... Aluminide protective coatings have been in use on nickel a superalloys in gas turbines with a considerable degree of As a result a considerable amount of...used for the application of aluminide coatings to superalloy substitutes are those of chemical vapour deposition (CVÜ

  18. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion is one of the most serious and challenging problems faced worldwide by industry. This research investigates the inhibition of corrosive behavior of SAE1010 steel by bacterial exopolysaccharides. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion inhibition of diffe...

  19. Electrochemical measurements of cathodic protection for reinforced concrete piles in a marine environment using embedded corrosion monitoring sensors

    NASA Astrophysics Data System (ADS)

    Jeong, Jin-A.; Chung, Won-Sub; Kim, Yong-Hwan

    2013-05-01

    This study developed a sensor to monitor the corrosion of reinforced concrete structures. Concrete pile specimens with embedded sensors were used to obtain data on corrosion and cathodic protection for bridge columns in a real marine environment. Corrosion potential, cathodic protection current density, concrete resistivity, and the degree of depolarization potential were measured with the embedded sensors in concrete pile specimens. The cathodic protection (CP) state was accurately monitored by sensors installed in underwater, tidal, splash, and atmospheric zones. The protection potential measurements confirmed that the CP by Zn-mesh sacrificial anode was fairly effective in the marine pile environment. The protection current densities in the tidal, splash zones were 2-3 times higher than those in underwater and atmospheric zones. The concrete resistivity in the tidal and splash zones was decreased through the installation of both mortar-embedded Zn-mesh (sacrificial anode) and outside an FRP jacket (cover). Considering the CP, the cathodic prevention was more effective than cathodic protection.

  20. Cathodic protection of pre-tensioned concrete. Part 1: Brittle fracture propensity of corrosion damaged prestressing tendon wire

    SciTech Connect

    Stauder, A.L.; Hartt, W.H.

    1998-12-31

    Constant extension rate tests were performed upon prestressing wire specimens in air and in saturated Ca(OH), solution at {minus}0.90 and {minus}1.30 v (SCE) in order to investigate the influence of various levels of precorrosion upon mechanical properties and fracture behavior. It was determined that ultimate tensile strength (UTS) was reduced to a greater extent in the case of specimens which exhibited layer corrosion compared to those with simulated pits. The UTS of layer corroded specimens was not significantly influenced by corrosion morphology acuity but, instead, correlated with the magnitude of cross sectional area reduction. The results are discussed within the context of the previously proposed negative potential limit of {minus}0.90 v (SCE) for cathodic protection of prestressing steel, and a modified qualification criterion is introduced based upon a relationship between fracture load (alternatively, prestress level) and the magnitude of cross section reduction by corrosion.

  1. Corrosion Protection of Copper Using Al2O3, TiO2, ZnO, HfO2, and ZrO2 Atomic Layer Deposition.

    PubMed

    Daubert, James S; Hill, Grant T; Gotsch, Hannah N; Gremaud, Antoine P; Ovental, Jennifer S; Williams, Philip S; Oldham, Christopher J; Parsons, Gregory N

    2017-02-01

    Atomic layer deposition (ALD) is a viable means to add corrosion protection to copper metal. Ultrathin films of Al2O3, TiO2, ZnO, HfO2, and ZrO2 were deposited on copper metal using ALD, and their corrosion protection properties were measured using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). Analysis of ∼50 nm thick films of each metal oxide demonstrated low electrochemical porosity and provided enhanced corrosion protection from aqueous NaCl solution. The surface pretreatment and roughness was found to affect the extent of the corrosion protection. Films of Al2O3 or HfO2 provided the highest level of initial corrosion protection, but films of HfO2 exhibited the best coating quality after extended exposure. This is the first reported instance of using ultrathin films of HfO2 or ZrO2 produced with ALD for corrosion protection, and both are promising materials for corrosion protection.

  2. Shop primer as part of the corrosion protective coating for submerged steel structures

    SciTech Connect

    Bjordal, M.; Steinsmo, U.

    1998-12-31

    In Norwegian workshops the standard pre-treatment procedures for steel structures intended for sub-sea use, normally include removal of shop primer by blast cleaning to Sa 2 1/2 before application of corrosion protective coatings. This is also stated in the Norwegian offshore standard NORSOK. Omitting this stage in fabrication will represent large reductions in both time consumption and costs, and reduce the volume of waste from the blast cleaning. This report presents results from investigations of how a shop primer will influence on the coating properties. The aim of the investigation was to test whether the systems are good enough if the shop primer is left on the surface. Two different zinc silicate shop primers have been included in the investigation. As protective coatings the authors have used three different epoxy mastic systems with Al pigments. In addition to panels with original shop primer, they have also tested shop primed panels pre-treated in various ways, such as heated, corroded and blast cleaned to various degrees before coating. The coatings have been tested in the ASTM-G8 121 test and in a long term test in sea water polarized with a Zn anode. They have found that coatings including the zinc silicate shop primer are more susceptible to cathodic disbonding than the coating applied directly on blast cleaned steel. It is however possible to meet the NORSOK criteria with a zinc silicate shop primer as first coat.

  3. Series elastic actuators

    NASA Astrophysics Data System (ADS)

    Williamson, Matthew M.

    1995-01-01

    This thesis presents the design, construction, control and evaluation of a novel for controlled actuator. Traditional force controlled actuators are designed from the premise that 'Stiffer is better'. This approach gives a high bandwidth system, prone to problems of contact instability, noise, and low power density. The actuator presented in this thesis is designed from the premise that 'Stiffness isn't everything'. The actuator, which incorporates a series elastic element, trades off achievable bandwidth for gains in stable, low noise force control, and protection against shock loads. This thesis reviews related work in robot force control, presents theoretical descriptions of the control and expected performance from a series elastic actuator, and describes the design of a test actuator constructed to gather performance data. Finally the performance of the system is evaluated by comparing the performance data to theoretical predictions.

  4. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.

    PubMed

    Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

    2011-06-01

    Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

  5. Corrosion Protection of Nd-Fe Magnets via Phophatization, Silanization and Electrostatic Spraying with Organic Resin Composite Coatings

    NASA Astrophysics Data System (ADS)

    Ding, Xia; Li, Jingjie; Li, Musen; Ge, Shengsong; Wang, Xiuchun; Ding, Kaihong; Cui, Shengli; Sun, Yongcong

    2014-09-01

    Nd-Fe-B permanent magnets possess excellent properties. However, they are highly sensitive to the attack of corrosive environment. The aim of this work is to improve the corrosion resistance of the magnets by phosphatization, silanization, and electrostatic spraying with organic resin composite coatings. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS) tests showed that uniform phosphate conversion coatings and spray layers were formed on the surface of the Nd-Fe-B magnets. Neutral salt spray tests exhibited that, after treated by either phosphating, silanization or electrostatic spraying, the protectiveness of Nd-Fe-B alloys was apparently increased. And corrosion performance of magnets treated with silane only was slightly inferior to those of phosphatized ones. However, significant improvement in corrosion protection was achieved after two-step treatments, i.e. by top-coating spray layer with phosphate or silane films underneath. Grid test indicated that the phosphate and silane coating were strongly attached to the substrate while silane film was slightly weaker than the phosphate-treated ones. Magnetic property analysis revealed phosphatization, silanization, and electrostatic spraying caused decrease in magnetism, but silanization had the relatively smaller effect.

  6. A new dioxime corrosion inhibitor for the protection and conservation of copper: synthesis, characterization and evaluation in acidic chloride solution

    NASA Astrophysics Data System (ADS)

    Abu-Baker, Ahmad N.; Al-Qudah, Mahmoud A.

    2016-08-01

    This study aimed to investigate a new dioxime compound as a corrosion inhibitor for copper. The compound (4,6-dihydroxy benzene-1,3-dicarbaldehyde dioxime) was synthesized and characterized by nuclear magnetic resonance spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements were used to compare the dioxime compound with benzotriazole for their effectiveness as corrosion inhibitors for copper in 0.1 M HCl solution. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to investigate the bonding mechanisms and morphological changes of the two inhibitors on the copper surface. The electrochemical techniques showed that the new dioxime compound was more effective than benzotriazole in inhibiting copper corrosion in the acidic chloride medium. The FTIR and SEM results indicated that the dioxime compound was able to coordinate with copper ions and formed a protective film on the copper surface. It was concluded that the new dioxime compound proved effectiveness to be used as a corrosion inhibitor for the protection and conservation of copper.

  7. Application of Terahertz Radiation to the Detection of Corrosion under the Shuttle's Thermal Protection System

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Anastasi, Robert F.; Smith, Stephen W.; Seebo, Jeffrey P.; Walker, James L.; Lomness, Janice K.; Hintze, Paul E.; Kammerer, Catherine C.; Winfree, William P.; Russell, Richard W.

    2007-01-01

    There is currently no method for detecting corrosion under Shuttle tiles except for the expensive process of tile removal and replacement; hence NASA is investigating new NDE methods for detecting hidden corrosion. Time domain terahertz radiation has been applied to corrosion detection under tiles in samples ranging from small lab samples to a Shuttle with positive results. Terahertz imaging methods have been able to detect corrosion at thicknesses of 5 mils or greater under 1" thick Shuttle tiles and 7-12 mils or greater under 2" thick Shuttle tiles.

  8. Synthesis of Graphene Oxide-Based Sulfonated Oligoanilines Coatings for Synergistically Enhanced Corrosion Protection in 3.5% NaCl Solution.

    PubMed

    Lu, Hao; Zhang, Shengtao; Li, Weihua; Cui, Yanan; Yang, Tao

    2017-02-01

    As a vital derivative of graphene, graphene oxide (GO) is widely applied in various fields, such as transparent electrodes, solar cells, energy storage, and corrosion protection due to the large specific surface area and abundant active sites. However, compared with graphene, the application of GO has been less reported in metal corrosion protection field. Therefore, in our study, 3-aminobenzenesulfonic acid was selected to combine with oligoanilines to fabricate the GO-based sulfonated oligoanilines coatings for marine corrosion protection application. The obtained composite coatings were covered on the surface of Q235 steel, which is one of the most important structural marine materials. Fourier transform infrared spectra were utilized to prove the existence of different bonds and functional groups of aniline trimer and sulfonated aniline trimer (SAT). Scanning electron microscopy was applied to verify the combination of GO and SAT. What's more, transmission electron microscopy was applied to observe the surface appearance of the obtained GO-SAT composite material. Besides, the results of electrochemical measurements performed in 3.5 wt % NaCl solution showed excellent corrosion-protective properties of GO/SAT-coated epoxy resin with a dosage of 10 mg of GO compared with the pure epoxy resin. Moreover, the enhancement of surface hydrophobic property, to some extent, is in favor of preventing the absorption of corrosive medium and water molecules revealed by contact angle test. The addition of GO can make the diffusion pathway of the corrosive medium longer and more circuitous, while SAT has displayed excellent solvent solubility while maintaining corrosion-protective properties similar to those of polyanilines so that the corrosion-protective properties of the modified coatings improve significantly due to the synergistically enhanced corrosion protection of GO and SAT.

  9. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. Dry lubricants reduce friction between two metal surfaces. This research investigated the inhibition of corrosive behavior a dry lubricant formulation consisting of jet-cooked corn starch and soyb...

  10. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced 3 worldwide by industry. This research investigated the inhibition of corrosive behavior a 4 dry lubricant formulation consisting of jet-cooked corn starch and soybean oil on SAE 5 1010 steel. Electrochemical Impedance ...

  11. Corrosion Protection of Steel by Thin Coatings of Starch-oil Emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. This research investigated the inhibition of corrosive behavior by jet-cooked starch-soybean oil composites on SAE 1010 steel. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate t...

  12. EXPERIMENTAL STUDY ON EFFECTS OF CATHODIC PROTECTION TO PREVENT MACRO-CELL CORROSION OF STEEL IN CONCRETE

    NASA Astrophysics Data System (ADS)

    Yamamoto, Satoru; Ueno, Moe; Ishii, Kouji; Seki, Hiroshi

    Reinforcing bars embedded in concrete tend to corrode due to salt attack under marine environments. Corrosion of bars might be often caused with phenomenon of macro-cell. Cathodic protection has been, so far, applied to control the corrosion of reinforcing bars in RC members. In order to make clear the mechanisms of macro-cell corr osion and the effect of cathodic protecti on, laboratory tests were carried out. Testing concrete specimens contained two reinforcing bars which were buried at upper area of specimens and at lower area of ones, respectively. Lower zone of the concrete specimens were immersed in water. Testing results indicated as follows: (1) reinforci ng bars under wetting condition were anode and reinforcing bars under drying one cathode, (2) current density of macro-cell between two bars increased according as the potential difference increased and electric resistance of the concrete between two bars decreased, and (3) cathodic protection was effective to prevented macro-cell corrosion of reinforcing bars in concrete. Furthermore, it was presumed that corroded iron might be reduced to metal iron due to the protection current.

  13. The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1995-01-01

    The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

  14. Shape Memory Actuator System

    DTIC Science & Technology

    1998-07-31

    The advantage in utilizing 15 shape-memory cables made of Nitinol for size reduction of the remote control actuator system is 1 Fi well suited for...a submarine environment because of its non-magnetic and corrosion resistance 17 properties. Use of thermoelastic Nitinol introduces other...problems because of the cooling and 18 resetting properties of Nitinol cables. It is therefore an important object of the present invention 19 on to

  15. Machine Protection System for the Stepper Motor Actuated SyLMAND Mirrors

    SciTech Connect

    Subramanian, V. R.; Dolton, W.; Wells, G.; Hallin, E.; Achenbach, S.; Klymyshyn, D. M.; Augustin, M.

    2010-06-23

    SyLMAND, the Synchrotron Laboratory for Micro and Nano Devices at the Canadian Light Source, consists of a dedicated X-ray lithography beamline on a bend magnet port, and process support laboratories in a clean room environment. The beamline includes a double mirror system with flat, chromium-coated silicon mirrors operated at varying grazing angles of incidence (4 mrad to 45 mrad) for spectral adjustment by high energy cut-off. Each mirror can be independently moved by two stepper motors to precisely control the pitch and vertical position. We present in this paper the machine protection system implemented in the double mirror system to allow for safe operation of the two mirrors and to avoid consequences of potential stepper motor malfunction.

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

    SciTech Connect

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

    1996-10-01

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

  17. Corrosion protection of aerospace grade magnesium alloy Elektron 43(TM) for use in aircraft cabin interiors

    NASA Astrophysics Data System (ADS)

    Baillio, Sarah S.

    Magnesium alloys exhibit desirable properties for use in transportation technology. In particular, the low density and high specific strength of these alloys is of interest to the aerospace community. However, the concerns of flammability and susceptibility to corrosion have limited the use of magnesium alloys within the aircraft cabin. This work studies a magnesium alloy containing rare earth elements designed to increase resistance to ignition while lowering rate of corrosion. The microstructure of the alloy was documented using scanning electron microscopy. Specimens underwent salt spray testing and the corrosion products were examined using energy dispersive spectroscopy.

  18. Corrosion protection of Al alloys and Al-based metal-matrix composites by chemical passivation

    SciTech Connect

    Mansfeld, F.; Lin, S.; Sim, S.; Shih, H.

    1989-08-01

    Chemical passivation by immersion of aluminium alloys and aluminium 6061/ silicon carbide and aluminium 6061/graphite metal-matrix composites in cerium chloride solution produces very corrosion-resistant surfaces. Aluminium 6061 and aluminium 7075-T6 that had been immersed in 1000 ppm cerium chloride for one week did not suffer from pitting corrosion during immersion in acerated 0.5 N NaCl for three weeks. For aluminium 7075-T7l3 some improvement of the corrosion resistance was also achieved, but to a much lesser extent. Chemical passivation in cerium chloride was also successful for aluminium/silicon carbide and Allgraphite.

  19. Synthesis of hybrid sol-gel coatings for corrosion protection of we54-ae magnesium alloy

    NASA Astrophysics Data System (ADS)

    Hernández-Barrios, C. A.; Duarte, N. Z.; Hernández, L. M.; Peña, D. Y.; Coy, A. E.; Viejo, F.

    2013-11-01

    The present work shows some preliminary results related to the synthesis, characterization and corrosion evaluation of different hybrid sol-gel coatings applied on the WE54-AE magnesium alloy attending to the two experimental variables, i.e. the precursors ratio and the aging time, which may affect the quality and the electrochemical properties of the coatings resultant. The experimental results confirmed that, under some specific experimental conditions, it was possible to obtain homogeneous and uniform, porous coatings with good corrosion resistance that also permit to accommodate corrosion inhibitors.

  20. A systematic multiscale modeling and experimental approach to protect grain boundaries in magnesium alloys from corrosion

    SciTech Connect

    Horstemeyer, Mark R.; Chaudhuri, Santanu

    2015-09-30

    A multiscale modeling Internal State Variable (ISV) constitutive model was developed that captures the fundamental structure-property relationships. The macroscale ISV model used lower length scale simulations (Butler-Volmer and Electronics Structures results) in order to inform the ISVs at the macroscale. The chemomechanical ISV model was calibrated and validated from experiments with magnesium (Mg) alloys that were investigated under corrosive environments coupled with experimental electrochemical studies. Because the ISV chemomechanical model is physically based, it can be used for other material systems to predict corrosion behavior. As such, others can use the chemomechanical model for analyzing corrosion effects on their designs.

  1. The corrosion protection of AA2024-T3 aluminium alloy by leaching of lithium-containing salts from organic coatings.

    PubMed

    Visser, Peter; Liu, Yanwen; Zhou, Xiaorong; Hashimoto, Teruo; Thompson, George E; Lyon, Stuart B; van der Ven, Leendert G J; Mol, Arjan J M C; Terryn, Herman A

    2015-01-01

    Lithium carbonate and lithium oxalate were incorporated as leachable corrosion inhibitors in model organic coatings for the protection of AA2024-T3. The coated samples were artificially damaged with a scribe. It was found that the lithium-salts are able to leach from the organic coating and form a protective layer in the scribe on AA2024-T3 under neutral salt spray conditions. The present paper shows the first observation and analysis of these corrosion protective layers, generated from lithium-salt loaded organic coatings. The scribed areas were examined by scanning and transmission electron microscopy before and after neutral salt spray exposure (ASTM-B117). The protective layers typically consist of three different layered regions, including a relatively dense layer near the alloy substrate, a porous middle layer and a flake-shaped outer layer, with lithium uniformly distributed throughout all three layers. Scanning electron microscopy and white light interferometry surface roughness measurements demonstrate that the formation of the layer occurs rapidly and, therefore provides an effective inhibition mechanism. Based on the observation of this work, a mechanism is proposed for the formation of these protective layers.

  2. Niobium-based sputtered thin films for corrosion protection of proton-irradiated liquid water targets for [18F] production

    NASA Astrophysics Data System (ADS)

    Skliarova, H.; Azzolini, O.; Cherenkova-Dousset, O.; Johnson, R. R.; Palmieri, V.

    2014-01-01

    Chemically inert coatings on Havar® entrance foils of the targets for [18F] production via proton irradiation of enriched water at pressurized conditions are needed to decrease the amount of ionic contaminants released from Havar®. In order to find the most effective protective coatings, the Nb-based coating microstructure and barrier properties have been correlated with deposition parameters such as substrate temperature, applied bias, deposition rate and sputtering gas pressure. Aluminated quartz used as a substrate allowed us to verify the protection efficiency of the desirable coatings as diffusion barriers. Two modelling corrosion tests based on the extreme susceptibility of aluminum to liquid gallium and acid corrosion were applied. Pure niobium coatings have been found to be less effective barriers than niobium-titanium coatings. But niobium oxide films, according to the corrosion tests performed, showed superior barrier properties. Therefore multi-layered niobium-niobium oxide films have been suggested, since they combine the high thermal conductivity of niobium with the good barrier properties of niobium oxide.

  3. Corrosion Protection Mechanisms of Rare-Earth Compounds Based on Cerium and Praseodymium

    DTIC Science & Technology

    2012-04-01

    changes in the concentrations of inhibitor species in primers containing Pr- based corrosion inhibitors as a function of time in salt spray testing (Task 4...citric acid , forming a cerium citrate complex, and the second was an aqueous solution of H3PO4. The concentrations and ratios of individual species...were varied experimentally to optimize the morphology and corrosion performance of the coatings. Precursor concentrations designed to yield 60 g/L

  4. The development of chemically vapor deposited mullite coatings for the corrosion protection of SiC

    SciTech Connect

    Auger, M.; Hou, P.; Sengupta, A.; Basu, S.; Sarin, V.

    1998-05-01

    Crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance the corrosion and oxidation resistance of the substrate. Current research has been divided into three distinct areas: (1) Development of the deposition processing conditions for increased control over coating`s growth rate, microstructure, and morphology; (2) Analysis of the coating`s crystal structure and stability; (3) The corrosion resistance of the CVD mullite coating on SiC.

  5. Corrosion protection of SiC-based ceramics with CVD mullite coatings

    SciTech Connect

    Auger, M.L.; Sarin, V.K.

    1997-12-01

    For the first time, crystalline mullite coatings have been chemically vapor deposited on SiC substrates to enhance its corrosion and oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments.

  6. Experimental Design for the Evaluation of Detection Techniques of Hidden Corrosion Beneath the Thermal Protective System of the Space Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Kemmerer, Catherine C.; Jacoby, Joseph A.; Lomness, Janice K.; Hintze, Paul E.; Russell, Richard W.

    2007-01-01

    The detection of corrosion beneath Space Shuttle Orbiter thermal protective system is traditionally accomplished by removing the Reusable Surface Insulation tiles and performing a visual inspection of the aluminum substrate and corrosion protection system. This process is time consuming and has the potential to damage high cost tiles. To evaluate non-intrusive NDE methods, a Proof of Concept (PoC) experiment was designed and test panels were manufactured. The objective of the test plan was three-fold: establish the ability to detect corrosion hidden from view by tiles; determine the key factor affecting detectability; roughly quantify the detection threshold. The plan consisted of artificially inducing dimensionally controlled corrosion spots in two panels and rebonding tile over the spots to model the thermal protective system of the orbiter. The corrosion spot diameter ranged from 0.100" to 0.600" inches and the depth ranged from 0.003" to 0.020". One panel consisted of a complete factorial array of corrosion spots with and without tile coverage. The second panel consisted of randomized factorial points replicated and hidden by tile. Conventional methods such as ultrasonics, infrared, eddy current and microwave methods have shortcomings. Ultrasonics and IR cannot sufficiently penetrate the tiles, while eddy current and microwaves have inadequate resolution. As such, the panels were interrogated using Backscatter Radiography and Terahertz Imaging. The terahertz system successfully detected artificially induced corrosion spots under orbiter tile and functional testing is in-work in preparation for implementation.

  7. Corrosion protection comparison of a chromate conversion coating to a novel conductive polymer coating on aluminum alloys

    SciTech Connect

    Racicot, R.J.; Yang, S.C.; Brown, R.

    1997-12-01

    Comparisons of the corrosion resistance performance of a novel polyaniline based double strand conductive polymer coating versus a chromate conversion coating on two aluminum alloys were made. Potentiodynamic scans, electrochemical impedance spectroscopy (EIS) in 0.5N NaCl solutions and ASTM B-117 salt spray tests were performed on coated samples of AA7075-T6 and AA2024-T3 aluminum alloys. Results show the conductive polymer film offers, at the least, an equivalent protection performance as the chromate coating with a two order of magnitude reduction in corrosion current densities in cyclic polarization tests, near equivalent impedance values and less undercutting of a scribed area in salt spray test samples. In an acidic salt solution of pH 3.6, the conductive polymer offers an improved performance with a one order of magnitude higher impedance over the chromate coatings.

  8. Fe-Al Weld Overlay and High Velocity Oxy-Fuel Thermal Spray Coatings for Corrosion Protection of Waterwalls in Fossil Fired Plants with Low NOx Burners

    SciTech Connect

    Regina, J.R.

    2002-02-08

    Iron-aluminum-chromium coatings were investigated to determine the best candidates for coatings of boiler tubes in Low NOx fossil fueled power plants. Ten iron-aluminum-chromium weld claddings with aluminum concentrations up to 10wt% were tested in a variety of environments to evaluate their high temperature corrosion resistance. The weld overlay claddings also contained titanium additions to investigate any beneficial effects from these ternary and quaternary alloying additions. Several High-Velocity Oxy-Fuel (HVOF) thermal spray coatings with higher aluminum concentrations were investigated as well. Gaseous corrosion testing revealed that at least 10wt%Al is required for protection in the range of environments examined. Chromium additions were beneficial in all of the environments, but additions of titanium were beneficial only in sulfur rich atmospheres. Similar results were observed when weld claddings were in contact with corrosive slag while simultaneously, exposed to the corrosive environments. An aluminum concentration of 10wt% was required to prevent large amounts of corrosion to take place. Again chromium additions were beneficial with the greatest corrosion protection occurring for welds containing both 10wt%Al and 5wt%Cr. The exposed thermal spray coatings showed either significant cracking within the coating, considerable thickness loss, or corrosion products at the coating substrate interface. Therefore, the thermal spray coatings provided the substrate very little protection. Overall, it was concluded that of the coatings studied weld overlay coatings provide superior protection in these Low NOx environments; specifically, the ternary weld composition of 10wt%Al and 5wt%Cr provided the best corrosion protection in all of the environments tested.

  9. Synthesis and characterization of novel coatings for corrosion protection and hydrogen embrittlement inhibition

    NASA Astrophysics Data System (ADS)

    Durairajan, Anand

    The degradation of metallic materials under the effect of corrosion is a costly problem, which nearly every industry is confronted with. By using electrochemical plating, one can alter the characteristics of a surface so as to provide improved appearance, ability to withstand corrosive agents, resistance to abrasion, improved electrocatalytic properties or other desired properties or a combination of them. The primary goal of this dissertation is to use electrochemical deposition (electrolytic and electroless) as a surface modification technique to obtain corrosion resistant high performance electrode materials for different electrochemical applications. Metal hydride alloys, which reversibly absorb/desorb hydrogen, have been used in battery applications. The continuous decrease in the absorb/desorbing capacity of these alloys has been attributed to the corrosion of the alloy. Cobalt encapsulation (electroless) has been used as a surface modification method to obtain high performance AB5 type metal hydride alloy. The coated material has a higher capacity and longer cycle life compared to the bare alloy. Pulverization and alloy oxidation---two prime reasons for capacity fading of MH alloys have been studied in greater detail using unique electrochemical and physical characterization methods. The harmful effects of hydrogen permeation (ingress) and related stress corrosion cracking (SCC) can limit the use of metals and alloys in aqueous environments. In the present work, a new Zn-Ni-Cd plating process which offers a unique way of controlling and optimizing the Zn and Cd contents in the final deposit, has been developed. The Zn Ni-Cd alloy coatings has a more anodic corrosion potential than that of Cd but higher than the corrosion potential of iron. The coatings have superior corrosion resistance (10 times higher) and barrier properties than the conventional Cd coatings. Zn-Ni-Cd coatings also inhibit the hydrogen entry into the underlying steel. The kinetic

  10. Friction surfacing for enhanced surface protection of marine engineering components: erosion-corrosion study

    NASA Astrophysics Data System (ADS)

    Rajakumar, S.; Balasubramanian, V.; Balakrishnan, M.

    2016-08-01

    Good mechanical properties combined with outstanding corrosion-resistance properties of cast nickel-aluminum bronze (NAB) alloy lead to be a specific material for many marine applications, including ship propellers. However, the erosion-corrosion resistance of cast-NAB alloy is not as good as wrought NAB alloy. Hence, in this investigation, an attempt has been made to improve the erosion-corrosion resistance of cast NAB alloy by depositing wrought (extruded) NAB alloy applying the friction surfacing (FS) technique. Erosion-corrosion tests were carried out in slurries composed of sand particles of 3.5% NaCl solution. Silica sand having a nominal size range of 250-355 μm is used as an erodent. Specimens were tested at 30° and 90° impingement angles. It is observed that the erosion and erosion-corrosion resistance of friction surfaced NAB alloy exhibited an improvement as compared to cast NAB alloy. Scanning electron microscope (SEM) analysis showed that the erosion tracks developed on the cast NAB alloy were wider and deeper than those formed on the friction surfaced extruded NAB alloy.

  11. An investigation on corrosion protection of chromium nitride coated Fe-Cr alloy as a bipolar plate material for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Pan, T. J.; Zhang, B.; Li, J.; He, Y. X.; Lin, F.

    2014-12-01

    The corrosion properties of chromium nitride (CrN) coating are investigated to assess the potential use of this material as a bipolar plate for proton exchange membrane fuel cells (PEMFCs). Conductive metallic ceramic CrN layers are firstly deposited onto Fe-Cr alloy using a multi-arc ion plating technique to increase the corrosion resistance of the base alloy. Electrochemical measurements indicate that the corrosion resistance of the substrate alloy is greatly enhanced by the CrN coating. The free corrosion potential of the substrate is increased by more than 50 mV. Furthermore, a decrease in three orders of magnitude of corrosive current density for the CrN-coated alloy is observed compared to the as-received Fe-Cr alloy. Long-term immersion tests show that the CrN layer is highly stable and effectively acts as a barrier to inhibit permeation of corrosive species. On the contrary, corrosion of the Fe-Cr alloy is rather severe without the protection of CrN coating due to the active dissolution. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion process of the CrN/Fe-Cr alloy submerged in a simulated PEMFCs environment.

  12. Fighting Corrosion

    NASA Technical Reports Server (NTRS)

    2004-01-01

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

  13. Oleic acid-grafted chitosan/graphene oxide composite coating for corrosion protection of carbon steel.

    PubMed

    Fayyad, Eman M; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    2016-10-20

    An anticorrosion coating film based on the formation of nanocomposite coating is reported in this study. The composite consisted of chitosan (green matrix), oleic acid, and graphene oxide (nano filler). The nanocomposite coating was arranged on the surface of carbon steel, and the corrosion resistance was monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). Compared to the pure chitosan (CS) coating, the corrosion resistance of oleic acid-modified chitosan/graphene oxide film (CS/GO-OA) is increased by 100 folds. Since the well-dispersed smart grafted nanolayers delayed the penetration rate of corrosive species and thus maintained long term anticorrosive stability which is correlated with hydrophobicity and permeability.

  14. Development and evaluation of two PVD-coated β-titanium orthodontic archwires for fluoride-induced corrosion protection.

    PubMed

    Krishnan, Vinod; Krishnan, Anand; Remya, R; Ravikumar, K K; Nair, S Asha; Shibli, S M A; Varma, H K; Sukumaran, K; Kumar, K Jyothindra

    2011-04-01

    The present research was aimed at developing surface coatings on β titanium orthodontic archwires capable of protection against fluoride-induced corrosion. Cathodic arc physical vapor deposition PVD (CA-PVD) and magnetron sputtering were utilized to deposit thin films of titanium aluminium nitride (TiAlN) and tungsten carbide/carbon (WC/C) coatings on β titanium orthodontic archwires. Uncoated and coated specimens were immersed in a high fluoride ion concentration mouth rinse, following a specially designed cycle simulating daily use. All specimens thus obtained were subjected to critical evaluation of parameters such as electrochemical corrosion behaviour, surface analysis, mechanical testing, microstructure, element release, and toxicology. The results confirm previous research that β titanium archwires undergo a degradation process when in contact with fluoride mouth rinses. The study confirmed the superior nature of the TiAlN coating, evident as many fewer changes in properties after fluoride treatment when compared with the WC/C coating. Thus, coating with TiAlN is recommended in order to reduce the corrosive effects of fluorides on β titanium orthodontic archwires.

  15. Development of improved LACV-30 propeller blade coatings for protection against sand and rain erosion and marine environment corrosion

    NASA Astrophysics Data System (ADS)

    Malone, G. A.

    1983-05-01

    An investigation was conducted of candidate systems offering potential erosion and corrsion protection when applied as coatings to Aluminum 7075 alloy propeller blades used to propel air cushioned vehicles operating in severe environments such as offshore and marine beach logistics missions. Blade lifespans are significantly abbreviated by erosion from sand and water impingement. This work focused on special hard anodized and hard nickel electroplated coatings as candidate protective systems with sand/rain erosion testing to evaluate their merits. Results indicated that anodized coatings did not provide suitable erosion protection to Aluminum 7075 in sand/rain environments, even with dry film lubricant supplemental films. Electroplated hard nickel coatings, Vickers hardnesses in the range of 380 to 440, appeared better for combined sand/rain erosion resistance based on comparisons with prior work. Dilute phosphoric anodizing the aluminum substrates led to excellent bonds and improved corrosion resistance when subsequently plated with ductile nickel from a low pH bath, followed by hard nickel electroplate. Electrodeposited sacrificial corrosion coatings degraded the overall coating bond integrity.

  16. Hybrid nanostructured coatings for corrosion protection of base metals: a sustainability perspective

    NASA Astrophysics Data System (ADS)

    Dennis, Robert V.; Patil, Vikas; Andrews, Justin L.; Aldinger, Jeffrey P.; Yadav, Ganapati D.; Banerjee, Sarbajit

    2015-03-01

    In this topical review article, we attempt to capture recent advances in the development of sustainable hybrid nanocomposite coatings for the corrosion inhibition of structural metals. Spurred primarily by the urgent imperative of replacing hexavalent chromium but also driven by concerns regarding the environmental impact of organic solvents, materials criticality considerations, the need to maintain structural integrity and function under extreme environments, and a renewed impetus towards lightweighting, the design of new coating concepts has seen an explosion of activity. We discuss varying modes of corrosion inhibition and the drive towards multicomponent nanostructured coatings that synergistically unite multiple modes of corrosion inhibition within a single coating system. Nanocomposite coatings in which nanoparticles of one phase are dispersed within a continuous phase, usually a polymeric matrix, provide a modular design approach to multifunctional coatings provided fundamental challenges such as dispersion and compatibility can be resolved. By dint of their high surface-to-volume ratios, the incorporation of nanoparticles profoundly modifies the adjacent polymeric matrix, giving rise to an ‘interphase’ region with modified properties, at relatively low filler loadings. The implications of incorporating metallic, porous metal oxide, and carbon nanomaterials (graphene and carbon nanotubes) within polymeric matrices are explored with an emphasis on active corrosion inhibition. The availability of high-quality nanoparticles that are either electroactive (e.g., metals, graphene, carbon nanotubes, etc.) or are capable of serving as reservoirs for active corrosion inhibitors (e.g., porous silicon oxide, layered double hydroxides, halloysite) provides unprecedented functionality and opportunities for multifunctional coatings. The review emphasizes mechanistic considerations where these have been elucidated with a view towards developing systematic design

  17. Sputter-ion plating of coatings for protection of gas-turbine blades against high-temperature oxidation and corrosion

    NASA Technical Reports Server (NTRS)

    Coad, J. P.; Restall, J. E.

    1982-01-01

    Considerable effort is being devoted to the development of overlay coatings for protecting critical components such as turbine blades against high-temperature oxidation, corrosion, and erosion damage in service. The most commercially advanced methods for depositing coatings are electron-beam evaporation and plasma spraying. Sputter-ion plating (SIP) offers a potentially cheaper and simpler alternative method for depositing overlays. Experimental work on SIP of Co-Cr-Al-Y and Ni-Cr-Al-Ti alloy coatings is described. Results are presented of metallographic assessment of these coatings, and of the results obtained from high-velocity testing using a gas-turbine simulator rig.

  18. Corrosion Protection of Electro-Galvanized Steel by Ceria-Based Coatings: Effect of Polyethylene Glycol (PEG) Addition

    NASA Astrophysics Data System (ADS)

    Hamlaoui, Y.; Tifouti, L.; Pedraza, F.

    2013-09-01

    A cerium oxide thin layer was deposited onto galvanized steel by cathodic electrodeposition from 0.1 M concentrated cerium nitrate solution. In this work, the influence of polyethylene glycol (PEG) addition on the composition and morphology of the deposits is examined. The results showed that the addition of PEG to the cerium nitrate solutions leads to a decrease in the cracks in the deposits by decreasing the hydrogen reduction reaction and by decreasing the film thickness which provided enhanced corrosion protection. Moreover, the substrate dissolution reaction is inhibited.

  19. Civil Engineering Corrosion Control. Volume 2. Cathodic Protection Testing Methods and Instruments

    DTIC Science & Technology

    1975-01-01

    covered Cable CementSoft Soldered Joint Between 22 S.W.G. Silver Wire and Rubber- -: covered Copper Cable Cement Seal Silve Wire1/16" Dia. Holes 3...Corrosion of Copper and Its Alloys ", Heating. Piping and Air Conditioning, 1960 and April, 1961. 11. Kuhn, R. J., "Casings Promote Corrosion at Crossings...ELECTRODE1 Negative Potential to Saturated Metal Copper -Copoer Sulfate electrode Magnesium (Galvormag alloy )a 1.75 Magnesium (H-I alloy )a 1.55 Zinc

  20. Protection of NdFeB magnets by corrosion resistance phytic acid conversion film

    NASA Astrophysics Data System (ADS)

    Nan, Haiyang; Zhu, Liqun; Liu, Huicong; Li, Weiping

    2015-11-01

    Phytic acid conversion film was prepared on NdFeB magnets by dipping the NdFeB into phytic acid solution. The morphology, composition, structure and corrosion resistance of the film were systematically investigated. The results showed that the phytic acid film was effective in improving the corrosion resistance of NdFeB magnets. XRD, TEM and FT-IR analyses revealed that the film was amorphous and had a strong peak of phosphate radical (PO43-). The formation mechanism of the film was also explored by XPS and the potential of zero charge (Epzc) measurement at the solution-metal interface.

  1. Design of an Active Bumper with a Series Elastic Actuator for Pedestrian Protection of Small Unmanned Vehicles

    NASA Astrophysics Data System (ADS)

    Terumasa, Narukawa; Tomoki, Tsuge; Hiroshi, Yamamoto; Takahiro, Suzuki

    2016-09-01

    When autonomous unmanned vehicles are operated on sidewalks, the vehicles must have high safety standards such as avoiding injury when they come in contact with pedestrians. In this study, we established a design for preventing serious injury when such collisions occur. We designed an active bumper with a series elastic actuator, with the goal of avoiding serious injury to a pedestrian in a collision with a small unmanned vehicle. The series elastic actuator comprised an elastic element in series with a table driven by a ball screw and servo motor. The active bumper was used to control the contact force between a vehicle and a pedestrian. The optimal force for minimizing the deflection of the object of the collision was derived, and the actuator controlled to apply this optimal force. Numerical simulations showed that the active bumper was successful in improving the collision safety of small unmanned vehicles.

  2. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    1997-10-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO{sub 2} and H{sub 2} will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this six-month reporting period, we continued the work on the development and construction of the thermogravimetric chemical vapor deposition system that we intend to employ for studying the deposition of alumina, silica, and aluminosilicates (such as mullite) from mixtures of metal chlorides in H{sub 2} and CO{sub 2}. Specifically, we worked on the development of the tubular flow reactor that will be used for producing aluminum chloride for delivery to the chemical vapor deposition system and of the vapor and gas supply system. Various problems arising from condensation of aluminum chlorides in some sections of the supply line were resolved, and we expect to perform experiments using mixtures containing AlCl{sub 3} in the next reporting period. Preliminary experiments on the

  3. FUNCTIONALY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    PROF. STRATIS V. SOTIRCHOS

    1998-10-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO2 and H2 will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this six-month reporting period, the experimental work on the investigation of the deposition of alumina, silica, and aluminosilicates from mixtures of methyltrichlorosilane (MTS), aluminum trichloride, carbon dioxide, and hydrogen was continued. Experiments were also conducted on the deposition processes of the simple oxides, alumina and silica, from mixtures containing only one chloride (AlCl3 and MTS, respectively). Deposition rate data were obtained in a relatively broad range of operating conditions: temperatures in the range 800-1000 o C, 100 Torr pressure, 0.006-0.015 AlCl3 feed mole fraction, 0.011- 0.027 CH3SiCl3 feed mole fraction, and 0.004-0.07 CO2 feed mole fraction, and various positions along the axis of the deposition reactor. Since the effect of temperature had been

  4. FUNCTIONALLY GRADED ALUMINA/MULLITE COATINGS FOR PROTECTION OF SILICON CARBIDE CERAMIC COMPONENTS FROM CORROSION

    SciTech Connect

    1998-03-01

    The main objective of this research project is the formulation of processes that can be used to prepare compositionally graded alumina/mullite coatings for protection from corrosion of silicon carbide components (monolithic or composite) used or proposed to be used in coal utilization systems (e.g., combustion chamber liners, heat exchanger tubes, particulate removal filters, and turbine components) and other energy-related applications. Mullite will be employed as the inner (base) layer and the composition of the film will be continuously changed to a layer of pure alumina, which will function as the actual protective coating of the component. Chemical vapor deposition reactions of silica, alumina, and aluminosilicates (mullite) through hydrolysis of aluminum and silicon chlorides in the presence of CO{sub 2} and H{sub 2} will be employed to deposit compositionally graded films of mullite and alumina. Our studies will include the kinetic investigation of the silica, alumina, and aluminosilicate deposition processes, characterization of the composition, microstructure, surface morphology, and mechanical behavior of the prepared films, and modeling of the various deposition processes. During this reporting period, the construction and development of the chemical vapor deposition system was completed, and experiments were conducted on the deposition of alumina, silica, and aluminosilicates (such as mullite) from mixtures of AlCl{sub 3} and CH{sub 3}SiCl{sub 3} in CO{sub 2} and H{sub 2}. Work was mainly done on the investigation of the effects of the reaction temperature on the deposition kinetics. It was found that the temperature had a positive effect on the single oxides deposition rates and the codeposition rate. The apparent activation energy values extracted from the deposition rate vs. temperature curves in the high temperature region were similar for the three deposition processes, having a value around 20 kcal/mol. The codeposition rates were higher, by a

  5. 120 DEG C Cure, Durable, Corrosion Protection Powder Coatings for Temperature Sensitive Substrates

    DTIC Science & Technology

    2005-01-28

    inhibitor, (1- benzothiazol -2-ylthio) succinic acid (Irgacor 252LD) were also tested. 72 Table 5.2 Eight corrosion...23 Barium Metaborate C Nacorr 6401 Zinc Salt of Hydrophobic Sulfonic Acid D Busan 11-M1 Barium Metaborate Monohydrate E Irgacor 252LD (1- benzothiazol

  6. Polystyrene films as barrier layers for corrosion protection of copper and copper alloys.

    PubMed

    Románszki, Loránd; Datsenko, Iaryna; May, Zoltán; Telegdi, Judit; Nyikos, Lajos; Sand, Wolfgang

    2014-06-01

    Dip-coated polystyrene layers of sub-micrometre thickness (85-500nm) have been applied on copper and copper alloys (aluminium brass, copper-nickel 70/30), as well as on stainless steel 304, and produced an effective barrier against corrosion and adhesion of corrosion-relevant microorganisms. According to the dynamic wettability measurements, the coatings exhibited high advancing (103°), receding (79°) and equilibrium (87°) contact angles, low contact angle hysteresis (6°) and surface free energy (31mJ/m(2)). The corrosion rate of copper-nickel 70/30 alloy samples in 3.5% NaCl was as low as 3.2μm/a (44% of that of the uncoated samples), and in artificial seawater was only 0.9μm/a (29% of that of the uncoated samples). Cell adhesion was studied by fluorescence microscopy, using monoculture of Desulfovibrio alaskensis. The coatings not only decreased the corrosion rate but also markedly reduced the number of bacterial cells adhered to the coated surfaces. The PS coating on copper gave the best result, 2×10(3)cells/cm(2) (1% of that of the uncoated control).

  7. 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.

  8. Corrosion protection of copper by polypyrrole film studied by electrochemical impedance spectroscopy and the electrochemical quartz microbalance

    NASA Astrophysics Data System (ADS)

    Lei, Yanhua; Ohtsuka, Toshiaki; Sheng, Nan

    2015-12-01

    Polypyrrole (PPy) films were synthesized on copper in solution of sodium di-hydrogen phosphate and phytate for corrosion protection. The protection properties of PPy films were comparatively investigated in NaCl solution. During two months immersion, the PPy film doped with phytate anions, working as a cationic perm-selective membrane, inhibited the dissolution of copper to 1% of bare copper. Differently, the PPy film doped with di-hydrogen phosphate anions, possessing anionic perm-selectivity, was gradually reduced, and inhibited the dissolution to 7.8% of bare copper. Degradation of the PPy films was studied by comparing the electrochemical impedance spectroscopy change at different immersion time and Raman spectra change after immersion.

  9. Corrosion protection of metal implants by hard biocompatible ceramic coatings deposited by radio-frequency sputtering.

    PubMed

    Sella, C; Martin, J C; Lecoeur, J; Bellier, J P; Harmand, M F; Naji, A; Davidas, J P; Le Chanu, A

    1990-01-01

    Most metals used for orthopaedic and stomatology implants and prostheses belong to the families of titanium or nickel-based and cobalt-based superalloys designed for advanced technology industries (e.g. space, aeronautic and nuclear industries). Ideal materials should be as insoluble and biologically compatible as possible. In the present paper the corrosion behaviour of Ni-Cr and Co-Cr alloys in biological media is evaluated through potentiodynamic polarization tests. It is shown that these metals exhibit some minor release of the component elements and degradation products, which may induce cytotoxic and allergic effects. The corrosion resistance of these alloys can be strongly enhanced by hard ceramic coatings deposited by radio-frequency sputtering. The biocompatibility of coated and uncoated metals is compared from differentiated human cell cultures.

  10. Corrosion Protection Of Front Surface Aluminum Mirror Coatings With Dielectric Thin Films Deposited By Reactive Ion Plating

    NASA Astrophysics Data System (ADS)

    Guenther, Karl H.; Penny, Iain; Willey, Ronald R.

    1990-01-01

    Front surface metal mirrors need protection of the inherently fragile metal film normally deposited by evaporation in high vacuum. Dielectric thin films, also deposited by thermal or electron beam evaporation in high vacuum, provide limited protection because of their less than dense packing. These films usually have a columnar structure with voids between the columns. The voids give access to the metal film for humidity and corrosive gases or liquids. Sainty et al. [Appl. Opt. 23, 1116 (1984)] made some progress in developing better protective coatings with ion assisted deposition. We manufactured protected front surface aluminum mirrors using reactive ion plating deposition. When immersed in 0.2M NaOH, our best mirror survived for 20 hours while only degrading to a transmission of 10%, exceeding the results of Sainty et al. by a factor of 5 under the same test conditions. Electron beam evaporated dielectric coatings provided protection for about 1.5 to 2 hours in the same solution. We will discuss the reason for the significant improvement brought about by low voltage reactive ion plating deposition, and its advantage for large scale production.

  11. Evaluation of Zn-rich Primers and Rust Converters for Corrosion Protection of Steel

    DTIC Science & Technology

    2009-02-01

    phosphoric acid at ~15-33% wt., phosphoric and tannic acids , optimum conversion takes place from 3 to 12 months, thickness of oxide layer and its...barrier characteristics. 1.Gempler’s (water-based, tannic acid ) 2.Loctite rust treatment (polymeric-based, barium sulfate) 3.Total Solutions (water...based, tannic acid ) 4.Phoscote (phosphoric acid – current USMC product) 5.VpCI CorrVerter (combined rust converter and primer) 6.Corroseal (water-based

  12. Galvanic Liquid Applied Coating System For Protection of Embedded Steel Surfaces from Corrosion

    NASA Technical Reports Server (NTRS)

    Curran, Joseph; Curran, Jerome; Voska, N. (Technical Monitor)

    2002-01-01

    Corrosion of reinforcing steel in concrete is an insidious problem facing Kennedy Space Center (KSC), other Government Agencies, and the general public. These problems include KSC launch support structures, highway bridge infrastructure, and building structures such as condominium balconies. Due to these problems, the development of a Galvanic Liquid Applied Coating System would be a breakthrough technology having great commercial value for the following industries: Transportation, Infrastructure, Marine Infrastructure, Civil Engineering, and the Construction Industry. This sacrificial coating system consists of a paint matrix that may include metallic components, conducting agents, and moisture attractors. Similar systems have been used in the past with varying degrees of success. These systems have no proven history of effectiveness over the long term. In addition, these types of systems have had limited success overcoming the initial resistance between the concrete/coating interface. The coating developed at KSC incorporates methods proven to overcome the barriers that previous systems could not achieve. Successful development and continued optimization of this breakthrough system would produce great interest in NASA/KSC for corrosion engineering technology and problem solutions. Commercial patents on this technology would enhance KSC's ability to attract industry partners for similar corrosion control applications.

  13. 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.

  14. A synergistic combination of tetraethylorthosilicate and multiphosphonic acid offers excellent corrosion protection to AA1100 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Dalmoro, Viviane; dos Santos, João H. Z.; Armelin, Elaine; Alemán, Carlos; Azambuja, Denise S.

    2013-05-01

    This work describes a new mechanism for the incorporation of organophosphonic acid into silane self-assembly monolayers, which has been used to protect AA1100 aluminum alloy. The protection improvement has been attributed to the fact that phosphonic structures promote the formation of strongly bonded and densely packed monolayer films, which show higher surface coverage and better adhesion than conventional silane systems. In order to evaluate the linking chemistry offered by phosphonic groups, two functionalized organophosphonic groups have been employed, 1,2-diaminoethanetetrakis methylenephosphonic acid (EDTPO) and aminotrimethylenephosphonic acid (ATMP), and combined with tetraethylorthosilicate (TEOS) films prepared by sol-gel synthesis. Results suggest that phosphonic acids may interact with the surface through a monodentate and bidentate coordination mode and, in addition, form one or more strong and stable linkages with silicon through non-hydrolysable bonds. Therefore, the incorporation of a very low concentration of phosphonic acids on TEOS solutions favors the complete coverage of the aluminum substrate during the silanization process, which is not possible using TEOS alone. The linking capacity of phosphonic acid has been investigated by FTIR-RA spectroscopy, SEM and EDX analysis, X-ray photoelectron spectroscopy (XPS), and quantum mechanical calculations. Finally, electrochemical impedance spectroscopy has been used to study the corrosion protection revealing that EDTPO-containing films afforded more protection to the AA1100 substrate than ATMP-containing films.

  15. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Stoot, Adam C.; Camilli, Luca; Spiegelhauer, Susie-Ann; Yu, Feng; Bøggild, Peter

    2015-10-01

    Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel with Ni seed layer coated by a multi-layered graphene thin film (G/Ni/SS). The graphene film, synthesized by chemical vapour deposition (CVD), has a moderate amount of defects according to Raman spectroscopy. Short/medium-term corrosion test shows no significant advantage of using G/Ni/SS rather than Ni/SS, both samples exhibiting a similar trend, thus questioning the short-term positive effect of graphene coatings. However, partial immersion in boiling seawater for three weeks reveals a clear superiority of the graphene coating with respect to steel just protected by Ni. After the test, the graphene film is still intact with unchanged defect density. Our results show that even non-perfect multilayer graphene films can considerably increase the lifetime of future-generation bipolar plates for fuel cells.

  16. CORROSION INHIBITION

    DOEpatents

    Cartledge, G.H.

    1958-06-01

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

  17. Non-Chromated Coating Systems for Corrosion Protection of Aircraft Aluminum Alloys (Preprint)

    DTIC Science & Technology

    2006-04-01

    an HVLP 3 spray gun in an environmentally controlled paint booth at 75°F and 50% RH. Primers were mixed according to manufacturer’s...the performance of the standard chromate system in the following tests: ASTM B 117 Salt Spray [2], ASTM D 2803 Filiform Corrosion Test [3], ASTM D...weight between 40 and 60 mg/ft2. MSZ, a water-based sol-gel system, was applied by the manufacturer’s suggested spray method. The material was mixed

  18. Liquid uranium corrosion studies of protective yttria coatings on tantalum substrate

    NASA Astrophysics Data System (ADS)

    Alangi, Nagaraj; Mukherjee, Jaya; Anupama, P.; Verma, M. K.; Chakravarthy, Y.; Padmanabhan, P. V. A.; Das, A. K.; Gantayet, L. M.

    2011-03-01

    Yttrium oxide has excellent thermodynamic and thermal stability, and also exhibits superior resistance to attack by various reactive metals, glass and slag at high temperature. Coupons with yttrium oxide coating on tantalum substrate with out bond coat were tested for compatibility against liquid uranium at 1573 K up to 80 h in vacuum. Optical microscopy and SEM/EDS investigations were done to evaluate the micro structural features of the coating and the liquid uranium attack. Experimental results show that yttrium oxide coating exhibits excellent corrosion resistance against liquid uranium at 1573 K.

  19. Supersonic Particle Deposition for Repair and Corrosion Protection of Mg Gearboxes

    DTIC Science & Technology

    2009-09-02

    CP-Al = 63 Vickers 6061=105 Vickers Bond Strength >6061 has >10,000 psi on ZE41, AZ91 , and EV31 (CGT) >6061 surpassed 15,000 PSI for Triple Lug Shear...CP-Al/HP-Al has >=10,000 psi on ZE41 and AZ91 (K-Tech and CGT) RCB Fatigue Strength Minimal effect on both 7075-T6 and ZE41A Magnesium Alloy Salt Fog Corrosion >4000 hrs on CGT (on going) and 6000+ hrs for K-Tech Summary

  20. Photoelectrochemical protection of stainless alloys from the stress-corrosion cracking in BWR primary coolant environment

    SciTech Connect

    Akashi, Masatsune; Iso-o, Hiroyuki; Kubota, Nobuhiko; Fukuda, Takanori; Ayabe, Muneo; Hirano, Kenji

    1995-12-31

    The feasibility of counteracting or preventing the stress-corrosion cracking in the BWR core internals by the photoelectrochemical method has been examined. For the purpose TiO{sub 2} semiconductor is noted for its capability of photo electrochemically inducing the water-oxidizing anodic reaction in low enough potential domain if supplied with a light of a wavelength shorter than 410 nm. This paper offers an empirical proof by showing that Type 304 stainless steel and Alloy 600 stainless alloy that have been plasma-spray coated with TiO{sub 2} film will do quite well in environments of BWR primary coolant.

  1. Investigation of thermal spray coatings on austenitic stainless steel substrate to enhance corrosion protection

    NASA Astrophysics Data System (ADS)

    Rogers, Daniel M.

    The research is aimed to evaluate thermal spray coatings to address material issues in supercritical and ultra-supercritical Rankine cycles. The primary purpose of the research is to test, evaluate, and eventually implement a coating to improve corrosion resistance and increase efficiency of coal fired power plants. The research is performed as part of a comprehensive project to evaluate the ability of titanium, titanium carbide, or titanium diboride powders to provide fireside corrosion resistance in supercritical and ultra-supercritical steam boilers, specifically, coal driven boilers in Illinois that must utilize high sulfur and high chlorine content coal. [1] The powder coatings that were tested are nano-sized titanium carbide (TiC) and titanium di-boride (TiB2) powders that were synthesized by a patented process at Southern Illinois University. The powders were then sent to Gas Technology Institute in Chicago to coat steel coupons by HVOF (High Velocity Oxy-Fuel) thermal spray technique. The powders were coated on an austenitic 304H stainless steel substrate which is commonly found in high temperature boilers, pipelines, and heat exchangers. The samples then went through various tests for various lengths of time under subcritical, supercritical, and ultra-supercritical conditions. The samples were examined using a scanning electron microscope and x-ray diffraction techniques to study microstructural changes and then determined which coating performed best.

  2. Preparation of crosslinked amphiphilic silver nanogel as thin film corrosion protective layer for steel.

    PubMed

    Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdelrahman O

    2014-07-17

    Monodisperse silver nanoparticles were synthesized by a new developed method via reaction of AgNO3 and oleic acid with the addition of a trace amount of Fe3+ ions. Emulsion polymerization at room temperature was employed to prepare a core-shell silver nanoparticle with controllable particle size. N,N'-methylenebisacrylamide (MBA) and potassium peroxydisulfate (KPS) were used as a crosslinker, and as redox initiator system, respectively for crosslinking polymerization. The structure and morphology of the silver nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Monolayers of silver nanoparticle were self-assembled on the fresh active surface of the steel electrode and have been tested as a corrosion inhibitor for steel in 1 M HCl solution. The results of polarization measurements showed that nanogel particles act as a mixed type inhibitor.

  3. Oceanic corrosion test of bare and zinc-protected aluminum alloys for seawater heat exchangers

    NASA Technical Reports Server (NTRS)

    Sasscer, D. S.; Morgan, T. O.; Rivera, C.; Ernst, R.; Scott, A. C.; Summerson, T. J.

    1982-01-01

    Bare 3004 tubes, 7072 Alclad 3004 tubes, and bare and zinc diffusion treated 3003 extrusions from a brazed aluminum, plate-fin heat exchanger were exposed to 1.8 m/sec flowing seawater aboard an open ocean test facility moored 3.4 km off the southeast coast of Puerto Rico. After six months exposure, the average corrosion rates for most varieties of aluminum materials converged to a low value of 0.015 mm/yr (0.6 mils/yr). Pitting did not occur in bare 3003 and 3004 samples during the six month test. Pitting did occur to varying degrees in the Alclad and zinc diffusion treated material, but did not penetrate to the base metal. Biofouling countermeasures (intermittent chlorination and brushing) did not affect the corrosion rates to any significant extent. Intermittent chlorination at a level of 0.5 ppm for 28 minutes daily controlled microbiofouling of the samples but did not prevent the development of a macrobiofouling community in areas of the plumbing with low flow.

  4. Effect of amino-modified silica nanoparticles on the corrosion protection properties of epoxy resin-silica hybrid materials.

    PubMed

    Chang, Kung-Chin; Lin, Hui-Fen; Lin, Chang-Yu; Kuo, Tai-Hung; Huang, Hsin-Hua; Hsu, Sheng-Chieh; Yeh, Jui-Ming; Yang, Jen-Chang; Yu, Yuan-Hsiang

    2008-06-01

    In this paper, a series of organic-inorganic hybrid materials consisting of epoxy resin frameworks and dispersed nanoparticles of amino-modified silica (AMS) were successfully prepared. First of all, the AMS nanoparticles were synthesized by carrying out the conventional acid-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) in the presence of (3-aminopropyl)-trimethoxysilane (APTES) molecules. The as-prepared AMS nanoparticles were then characterized by FTIR, 13C-NMR and 29Si-NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in-situ thermal ring-opening polymerization reactions of epoxy resin in the presence of as-prepared AMS nanoparticles and raw silica (RS) particles. The as-prepared epoxy-silica hybrid materials with AMS nanoparticles were found to show better dispersion capability than that of RS particles existed in hybrid materials based on the morphological observation of transmission electron microscopy (TEM). The hybrid materials containing AMS nanoparticles in the form of coating on cold-rolled steel (CRS) were found to be much superior in corrosion protection over those of hybrid materials with RS particles when tested by a series of electrochemical measurements of potentiodynamic and impedance spectroscopy in 5 wt% aqueous NaCI electrolyte. The increase of corrosion protection effect of hybrid coatings may have probably resulted from the enhancement of the adhesion strength of the hybrid coatings on CRS coupons, which may be attributed to the formation of Fe-O-Si covalent bond at the interface of coating/CRS system based on the FTIR-RAS (reflection absorption spectroscopy) studies. The better dispersion capability of AMS nanoparticles in hybrid materials were found to lead more effectively enhanced molecular barrier property, mechanical strength, surface hydrophobicity and optical clarity as compared to that of RS particles, in the form of coating and membrane, based on the measurements of molecular

  5. Electrochemical corrosion studies

    NASA Technical Reports Server (NTRS)

    Knockemus, W. W.

    1986-01-01

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

  6. Temporary protection of metals against atmospheric corrosion by saturated straight chain aliphatic monocarboxylates. Mechanisms of inhibition

    SciTech Connect

    Kapin, C.; Steinmetz, P.; Steinmetz, J.

    1998-12-31

    This work was devoted to the investigations of the ability of saturated straight chain aliphatic monocarboxylates to inhibit corrosion of mild steel and zinc in aerated aqueous solutions. Performances of inhibitors were shown to be dependent on their chain length, their concentration and the immersion duration. Both crystallographic parameters and solubilities of iron and zinc carboxylates were determined. Then potential-pH diagrams of iron and zinc in water were built taking the presence of metallic soaps into account. According to these diagrams, the passivation of metals was attributed to the growth of films containing metallic soaps. This model confirms that previously proposed for inhibition of copper and magnesium by the same carboxylates.

  7. Electromechanical actuators

    NASA Technical Reports Server (NTRS)

    Bigham, J.

    1982-01-01

    Materials illustrating a presentation on the development of electromechanical actuators (EMA) for electric flight systems are presented. Technology issues are identified, and major steps relative to EMA development, NASA's role, and a technology procurement plan are outlined.

  8. Novel corrosion inhibitor technology

    SciTech Connect

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

    1999-11-01

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

  9. Applications of advanced electrochemical techniques in the study of microbial fuel cells and corrosion protection by polymer coatings

    NASA Astrophysics Data System (ADS)

    Manohar, Aswin Karthik

    determined by the sum of the polarization resistance of the anode (Rap) and the cathode (Rcp), and therefore Rint depends on V. The ohmic contribution to the Rint was very small. It has been found that Rint decreased with decreasing cell voltage as the increasing current flow decreased R ap and Rcp. In the presence of MR-1, Rint was lower by a factor of about 100 than Rint of the MFC with buffer and lactate as anolyte. Additions of SS balls to the anode compartment produced a very large decrease of Rint. For the MFC containing SS balls in the anode compartment no significant further decrease of Rint could be observed when MR-1 was added to the anolyte. In Chapter 2, EIS has been used to determine the properties and stability of polymer coatings based on different chromate or chromate-free pretreatments and primers. Five sets of coated aluminum 2024 samples were exposed to 0.5N NaCl for a period of 31 days. Impedance spectra of the samples were measured during this period and the changes of the properties of the different coatings were studied as a function of time. From the analysis of the fit parameters of the impedance spectra, it was found that the corrosion protection of the coated samples depended on the type of primer used. The coating with the chromate based primer provided better corrosion protection than the coating with the chromate free primer. After 31 days of exposure, one sample from each set was scribed and exposed to 0.5N NaCl. The corrosion behavior of the scribed coatings was found to be dependent upon the type of pretreatment employed. The samples with the chromate conversion coating pretreatment showed better corrosion resistance in the scribed area than the samples that were treated by the trivalent chromium based method.

  10. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete.

    PubMed

    Simescu, Florica; Idrissi, Hassane

    2008-12-01

    We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO4)6(OH)2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  11. Hybrid organic-inorganic network coatings for protecting metal substrates from abrasion and corrosion

    SciTech Connect

    Jordens, K.; Wilkes, G.

    1996-12-31

    Ceramers or Ormocers are hybrid organic-inorganic materials first created a decade ago, and are the subject of a recent review article. Recent research from the authors laboratory in this area of materials science has focused on synthesizing protective coatings for (soft) polymeric substrates, i.e. polycarbonate. The authors have now extended the application of such coatings to metallic substrates.

  12. Development of improved lacv-30 propeller blade coatings for protection against sand and rain erosion and marine environment corrosion. Final report 4 Jan 1982-4 Mar 1983

    SciTech Connect

    Malone, G.A.

    1983-05-10

    An investigation was conducted of candidate systems offering potential erosion and corrosion protection when applied as coatings to Aluminum 7075 alloy propeller blades used to propel air cushioned vehicles operating in severe environments. This work focused on (1) special hard anodized and (2) hard nickel electroplated coatings as candidate protective systems with sand/rain erosion testing to evaluate their merits. Attributes of the coating systems developed and studied included: For (1) Ways and means to produce and control deposit hardness for optimum erosion resistance, methods of bonding to blades for high integrity adhesion, and inclusion of sacrificial corrosion protection electroplates in the coating systems (zinc and zinc-nickel alloy). For (2) Incorporation of dry film lubricant systems on sealed hardcoats of various anodic coating thicknesses to enhance erosion performance. Study results indicated that anodized coatings did not provide suitable erosion protection to Aluminum 7075 in sand/rain environments, even with dry film lubricant supplemental films. Electroplated hard nickel coatings, Vickers hardnesses in the range of 380 to 440, appeared better for combined sand/rain erosion resistance based on comparisons with prior work. Dilute phosphoric anodizing the aluminum substrates led to excellent bonds and improved corrosion resistance when subsequently plated with ductile nickel from a low pH bath, followed by hard nickel electroplate.

  13. Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316 L stainless steel

    PubMed Central

    2012-01-01

    Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol–gel method for corrosion protection of 316 L stainless steel. Surface morphology, structure, and properties of the prepared coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion protection performance of the prepared coatings was evaluated in 3 wt% NaCl solution by using electrochemical techniques in the presence and absence of simulated sunlight illumination. The results indicated that the 1.2% Ce-TiO2 coating with three layers exhibited an excellent photogenerated cathodic protection under illumination attributed to the higher separation efficiency of electron–hole pairs and higher photoelectric conversion efficiency. The results also showed that after doping with an appropriate concentration of cerium nitrate, the anti-corrosion performance of the TiO2 coating was improved even without irradiation due to the self-healing property of cerium ions. PMID:22515192

  14. Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316 L stainless steel.

    PubMed

    Li, Suning; Wang, Qian; Chen, Tao; Zhou, Zhihua; Wang, Ying; Fu, Jiajun

    2012-04-19

    Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol-gel method for corrosion protection of 316 L stainless steel. Surface morphology, structure, and properties of the prepared coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion protection performance of the prepared coatings was evaluated in 3 wt% NaCl solution by using electrochemical techniques in the presence and absence of simulated sunlight illumination. The results indicated that the 1.2% Ce-TiO2 coating with three layers exhibited an excellent photogenerated cathodic protection under illumination attributed to the higher separation efficiency of electron-hole pairs and higher photoelectric conversion efficiency. The results also showed that after doping with an appropriate concentration of cerium nitrate, the anti-corrosion performance of the TiO2 coating was improved even without irradiation due to the self-healing property of cerium ions.

  15. Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel

    NASA Astrophysics Data System (ADS)

    Elsawy, Abdel Raouf

    This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation

  16. Refractory Materials for Flame Deflector Protection System Corrosion Control: Coatings Systems Literature Survey

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Coffman, Brekke E.; Coffman, Brekke E.; Curran, Jerome P.; Kolody, Mark R.; Whitten, Mary; Perisich, Steven; Trejo, David

    2009-01-01

    When space vehicles are launched, extreme heat, exhaust, and chemicals are produced and these form a very aggressive exposure environment at the launch complex. The facilities in the launch complex are exposed to this aggressive environment. The vehicle exhaust directly impacts the flame deflectors, making these systems very susceptible to high wear and potential failure. A project was formulated to develop or identify new materials or systems such that the wear and/or damage to the flame deflector system, as a result of the severe environmental exposure conditions during launches, can be mitigated. This report provides a survey of potential protective coatings for the refractory concrete lining on the steel base structure on the flame deflectors at Kennedy Space Center (KSC).

  17. Optimization of In-Situ Shot-Peening-Assisted Cold Spraying Parameters for Full Corrosion Protection of Mg Alloy by Fully Dense Al-Based Alloy Coating

    NASA Astrophysics Data System (ADS)

    Wei, Ying-Kang; Luo, Xiao-Tao; Li, Cheng-Xin; Li, Chang-Jiu

    2017-01-01

    Magnesium-based alloys have excellent physical and mechanical properties for a lot of applications. However, due to high chemical reactivity, magnesium and its alloys are highly susceptible to corrosion. In this study, Al6061 coating was deposited on AZ31B magnesium by cold spray with a commercial Al6061 powder blended with large-sized stainless steel particles (in-situ shot-peening particles) using nitrogen gas. Microstructure and corrosion behavior of the sprayed coating was investigated as a function of shot-peening particle content in the feedstock. It is found that by introducing the in-situ tamping effect using shot-peening (SP) particles, the plastic deformation of deposited particles is significantly enhanced, thereby resulting in a fully dense Al6061 coating. SEM observations reveal that no SP particle is deposited into Al6061 coating at the optimization spraying parameters. Porosity of the coating significantly decreases from 10.7 to 0.4% as the SP particle content increases from 20 to 60 vol.%. The electrochemical corrosion experiments reveal that this novel in-situ SP-assisted cold spraying is effective to deposit fully dense Al6061 coating through which aqueous solution is not permeable and thus can provide exceptional protection of the magnesium-based materials from corrosion.

  18. Electrodeposited conductive polypyrrole/polyaniline composite film for the corrosion protection of copper bipolar plates in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Pan, T. J.; Zuo, X. W.; Wang, T.; Hu, J.; Chen, Z. D.; Ren, Y. J.

    2016-01-01

    A conductive composite coating consisting of an inner polypyrrole (PPY) layer and an outer polyaniline (PANI) layer is prepared on a copper substrate by an electrochemical synthesis. Potential application of these composite coatings in a proton exchange membrane fuel cell (PEMFC) is evaluated. The corrosion performance of the copper substrate without and with the polymer coatings in the acidic solutions containing H2SO4 (0.2 M), HCl (0.1 M) and HF (3 ppm) is investigated by electrochemical impedance spectroscopy, polarization and open-circuit potential measurements. The results indicate that both the bilayered PPY/PANI and the single PPY coating can increase the corrosion potential of copper substrate by more than 250 mV (SCE), and effectively decrease the corrosion current density by an order of magnitude in comparison with the uncoated copper substrate. Long-term test further confirms that the bilayered PPY/PANI coating with acceptable contact resistance provides better protection for the substrate than the single PPY coating. The bilayered structure with different ion-permselective nature may serve as an effective physical barrier to the inward penetration of corrosive species.

  19. Corrosion and Protection of Metallic Interconnects in Solid Oxide Fuel Cells

    SciTech Connect

    Yang, Z Gary; Stevenson, Jeffry W.; Singh, Prabhakar

    2007-12-09

    Energy security and increased concern over environmental protection have spurred a dramatic world-wide growth in research and development of fuel cells, which electrochemically convert incoming fuel into electricity with no or low pollution. Fuel cell technology has become increasingly attractive to a number of sectors, including utility, automotive, and defense industries. Among the various types of fuel cells, solid oxide fuel cells (SOFCs) operate at high temperature (typically 650-1,000 C) and have advantages in terms of high conversion efficiency and the flexibility of using hydrocarbon fuels, in addition to hydrogen. The high temperature operation, however, can lead to increased mass transport and interactions between the surrounding environment and components that are required to be stable during a lifetime of thousands of hours and up to hundreds of thermal cycles. For stacks with relatively low operating temperatures (<800 C), the interconnects that are used to electrically connect a number of cells in series are typically made from cost-effective metals or alloys. The metallic interconnects must demonstrate excellent stability in a very challenging environment during SOFC operation, as they are simultaneously exposed to both an oxidizing (air) environment on the cathode side and a reducing environment (hydrogen or a reformed hydrocarbon fuel) on the anode side. Other challenges include the fact that water vapor is likely to be present in both of these environments, and the fuel is likely to contain impurities, such as sulfides. Since the fuel is usually a reformed hydrocarbon fuel, such as natural gas, coal gas, biogas, gasoline, etc., the interconnect is exposed to a wet carbonaceous environment at the anode side. Finally, the interconnect must be stable towards any adjacent components, such as electrodes, seals and electrical contact materials, with which it is in physical contact.

  20. Corrosion protection of solar-collctor heat exchangers with electrochemically deposited films. Final report, 15 May 1978-15 November 1979. [Polymers

    SciTech Connect

    Koch, V.R.; Schnaper, G.H.; Brummer, S.B.

    1980-05-01

    The goal of this program was the demonstration of a novel corrosion protection technique for the common solar collector metals: Al, Cu, and Fe as mild steel. This involves the electrochemical deposition of thin, adherent polymer films on the interior of heat-exchanger tubes by application of a current in the presence of a suitable organic monomer. Polyphenylene oxide (PPO) films were anodically deposited onto Cu and Fe coupons from methanolic media. However, defects in these films afforded poor corrosion protection. In an attempt to circumvent this problem, suitably functionalized PPO films were cross-linked via Schiff base formation in a subsequent chemical step. While these chemically modified PPO films were demonstrably more resistant to ethylene glycol H/sub 2/O media at elevated temperatures, they were eventually undetermined by the thermal transfer fluid. Cinnamaldehyde, a styrene-type monomre, has been successfully electrodeposited onto Al coupons. This process involved a constant, albeit unreferenced potential technique in which the Al is made the negative electrode. Cathodic deposition onto Al avoids passivating Al/sub 2/O/sub 3/ barrier coating formation, and is amenable to the cross-linking technique. Filmed and cross-linked Al samples stored at elevated temperatures resisted corrosive processes compared to unfilmed control samples. Pitting, however, was the ultimate fate of all filmed samples.

  1. Demonstration of multifunctional DNBM corrosion inhibitors in protective coatings for Naval Air/Weapon Systems. Final report, September 1989-July 1992

    SciTech Connect

    Bailin, L.J.

    1993-12-01

    The corrosion protective properties of multifunctional DNBM salts (quaternary ammonium dichromate, nitrate, borate, and molybdate) have been demonstrated on high-strength steel and aluminum alloys found in prototype aerospace weapon systems. The 100% DNBM mixture added to MIL-P-23377 epoxy-polyamide, minus strontium chromate inhibitor, on bare 7075-T6 aluminum alloy resisted 1000 h ASTM B-117 salt spray. However, the coatings were not resistant to hydraulic fluid immersion at the higher concentrations required for the corrosion inhibition. Microencapsulation of the reactive DNBM mixture was adopted as a means to prevent this susceptibility, as well as the destructive oxidation of the hydroxyl groups in the epoxy resin during cure. In the scale-up operation, approximately 20 gallons of DNBM weighing 64 kg (141 lb) was prepared from the four starting quarternary salts synthesized in a chemical process pilot plant. The salts were mixed by dissolving in toluene. Following removal of solvent, the resultant dark-brown liquid, approximating molasses in viscosity, was microencapsulated by the following method: The DNBM was dispersed to form an oil-in-water emulsion in an aqueous colloidal solution of low-viscosity, high-purity methyl cellulose using a Gifford-Wood homogenizer, followed by spray drying in an Anhydro spray dryer. The maximum practicable payload was 75% DNBM. After spray drying, the capsules Corrosion inhibitors, DNBM, Microencapsulation, Epoxy primers, Protective coatings.

  2. An evaluation of corrosion protection by two epoxy primers on 2219-T87 and 7075-T73 aluminum

    NASA Technical Reports Server (NTRS)

    Mendrek, M. J.

    1992-01-01

    A comparison of the corrosion protection provided by two amine epoxy primers was made using salt fog, alternate immersion, and total immersion as exposure media. The study is the result of a request to use an unqualified low volatile organic carbon (VOC) primer (AKZO 463-6-78) in place of the current primer (AKZO 463-6-3) because environmental regulations have eliminated use of the current primer in many states. Primed, scribed samples of 2219-T87 and 7075-T73 aluminum were exposed to 5-percent NaCl salt fog and 3.5-percent NaCl alternate immersion for a period of 90 days. In addition, electrode samples immersed in 3.5-percent NaCl were tested using electrochemical impedance spectroscopy (EIS). The EG&G model 368 ac impedance measurement system was used to monitor changing properties of AKZO 463-6-78 and AKZO 463-6-3 primed 2219-T87 aluminum for a period of 30 days. The response of the corroding system of a frequency scan can be modeled in terms of an equivalent circuit consisting of resistors and capacitors in a specific arrangement. Each resistor/capacitor combination represents physical processes taking place within the electrolyte, at the electrolyte/primer surface, within the coating, and at the coating/substrate surface. Values for the resistors and capacitors are assigned following a nonlinear least squares fit of the data to the equivalent circuit. Changes in the values of equivalent circuit parameters during the 30-day exposure allow assessment of the time to and mechanism of coating breakdown.

  3. 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.

  4. Modular droplet actuator drive

    NASA Technical Reports Server (NTRS)

    Pollack, Michael G. (Inventor); Paik, Philip (Inventor)

    2011-01-01

    A droplet actuator drive including a detection apparatus for sensing a property of a droplet on a droplet actuator; circuitry for controlling the detection apparatus electronically coupled to the detection apparatus; a droplet actuator cartridge connector arranged so that when a droplet actuator cartridge electronically is coupled thereto: the droplet actuator cartridge is aligned with the detection apparatus; and the detection apparatus can sense the property of the droplet on a droplet actuator; circuitry for controlling a droplet actuator coupled to the droplet actuator connector; and the droplet actuator circuitry may be coupled to a processor.

  5. Environmental Friendly Coatings and Corrosion Prevention For Flight Hardware Project

    NASA Technical Reports Server (NTRS)

    Calle, Luz

    2014-01-01

    Identify, test and develop qualification criteria for environmentally friendly corrosion protective coatings and corrosion preventative compounds (CPC's) for flight hardware an ground support equipment.

  6. The effect of cerium-based conversion treatment on the cathodic delamination and corrosion protection performance of carbon steel-fusion-bonded epoxy coating systems

    NASA Astrophysics Data System (ADS)

    Ramezanzadeh, B.; Rostami, M.

    2017-01-01

    The effect of surface pre-treatment of pipe surface by green cerium compound and phosphoric acid solution on the fusion-bonded epoxy (FBE) coating performance was studied. The composition and surface morphology of the steel samples treated by acid and Ce solutions were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), equipped with energy dispersive spectroscopy (EDS). Also, the surface free energy was evaluated on these samples through contact angle measurements. In addition, the effect of Ce and acid washing procedures on the adhesion properties and corrosion protection performance of the FBE was examined by pull-off, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results showed that compared to acid washing, the chemical treatment by Ce solution noticeably increased the surface free energy of steel, improved the adhesion properties of FBE, decreased the cathodic delamination rate of FBE, and enhanced the coating corrosion resistance compared to the acid washed samples.

  7. HVOF Thermal Spray TiC/TiB2 Coatings for AUSC Boiler/Turbine Components for Enhanced Corrosion Protection

    SciTech Connect

    Mondal, Kanchan; Koc, Rasit; Fan, Chinbay

    2016-12-07

    The high temperatures of operations still pose significant risk of degradation and fatigue from oxidizing, corroding and eroding environment. In addition to unused O2, water from combustion and SOx from the coal sulfur oxidation that result in highly corrosive environment, acid gases such as HCl and other sulfur compounds may also be present. These adverse effects are further accelerated due to the elevated temperatures. In addition, ash particulates and unburnt carbon and pyritic sulfur can cause erosion of the surface and thus loss of material. Unburnt carbon and pyritic sulfur may also cause localized reduction sites. Thus, fireside corrosion protection and steam oxidation protection alternatives to currently used Ni-Cr overlays need to be identified and evaluated. Titanium carbide (TiC) is a suitable alternative on account of the material features such as the high hardness, the high melting point, the high strength and the low density for the substitution or to be used in conjunction with NiCr for enhancing the fireside corrosion and erosion of the materials. Another alternative is the use of titanium boride as a coating for chemical stability required for long-term service and high erosion resistance over the state-of-the-art, high fracture toughness (K1C ~12 MPam1/2) and excellent corrosion resistance (kp~1.9X10-11 g2/cm4/s at 800°C in air). The overarching aim of the research endeavor was to synthesize oxidation, corrosion and wear resistant TiC and TiB2 coating powders, apply thermal spray coating on existing boiler materials and characterize the coated substrates for corrosion resistance for applications at high temperatures (500 -750 °C) and high pressures (~350 bars) using the HVOF process and to demonstrate the feasibility of these coating to be used in AUSC boilers and turbines.

  8. 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.

  9. 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.

  10. A Comparative Study on Ni-Based Coatings Prepared by HVAF, HVOF, and APS Methods for Corrosion Protection Applications

    NASA Astrophysics Data System (ADS)

    Sadeghimeresht, E.; Markocsan, N.; Nylén, P.

    2016-12-01

    Selection of the thermal spray process is the most important step toward a proper coating solution for a given application as important coating characteristics such as adhesion and microstructure are highly dependent on it. In the present work, a process-microstructure-properties-performance correlation study was performed in order to figure out the main characteristics and corrosion performance of the coatings produced by different thermal spray techniques such as high-velocity air fuel (HVAF), high-velocity oxy fuel (HVOF), and atmospheric plasma spraying (APS). Previously optimized HVOF and APS process parameters were used to deposit Ni, NiCr, and NiAl coatings and compare with HVAF-sprayed coatings with randomly selected process parameters. As the HVAF process presented the best coating characteristics and corrosion behavior, few process parameters such as feed rate and standoff distance (SoD) were investigated to systematically optimize the HVAF coatings in terms of low porosity and high corrosion resistance. The Ni and NiAl coatings with lower porosity and better corrosion behavior were obtained at an average SoD of 300 mm and feed rate of 150 g/min. The NiCr coating sprayed at a SoD of 250 mm and feed rate of 75 g/min showed the highest corrosion resistance among all investigated samples.

  11. Memory metal actuator

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F. (Inventor)

    1985-01-01

    A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

  12. Microencapsulation Technology for Corrosion Mitigation by Smart Coatings

    NASA Technical Reports Server (NTRS)

    Buhrow, Jerry; Li, Wenyan; Jolley, Scott; Calle, Luz M.

    2011-01-01

    A multifunctional, smart coating for the autonomous control of corrosion is being developed based on micro-encapsulation technology. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection effectiveness. This paper summarizes the development, optimization, and testing of microcapsules specifically designed to be incorporated into a smart coating that will deliver corrosion inhibitors to mitigate corrosion autonomously. Key words: smart coating, corrosion inhibition, microencapsulation, microcapsule, pH sensitive microcapsule, corrosion inhibitor, corrosion protection pain

  13. Corrosion Mitigation Strategies - an Introduction

    DTIC Science & Technology

    2009-02-05

    Control Technology – Cathodic protectionCorrosion inhibitors – Combination of methods • Balance cost and other factors Candidate Materials - Metals...Technology -UV, ozone,solvents,oxygen • Concrete -acids, chlorides, sulfates • Vitreous Materials-solvents • Corrosion Control • Waterproofing • Weather...Tar Enamel Leaders in Corrosion Control Technology – Tape – Concrete (Weight) Coating • Make metal to be protected act as a cathode • Application of

  14. Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate.

    PubMed

    Kaabi Falahieh Asl, Sara; Nemeth, Sandor; Tan, Ming Jen

    2016-11-01

    Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016.

  15. Two-shell structured PMAA@CeO2 nanocontainers loaded with 2-mercaptobenzothiazole for corrosion protection of damaged epoxy coated AA 2024-T3.

    PubMed

    Balaskas, A C; Hashimoto, T; Curioni, M; Thompson, G E

    2017-04-12

    In this work, novel two-shell structured inhibitor-loaded poly(methacrylic acid)@cerium oxide (PMAA@CeO2) nanocontainers were synthesised and characterized. The purpose of the nanocontainers is to increase the corrosion protection provided by an epoxy coating applied to an aerospace alloy (AA 2024-T3). The (PMAA@CeO2) nanocontainers with diameters of 550 nm were synthesised by a four-step process with the method of distillation precipitation polymerization for the synthesis of the inner PMAA layer, and the sol-gel method for the development of the outer CeO2 layer. The loaded nanocontainers were characterized by scanning and transmission electron microscopies. The corrosion protection properties of the epoxy coated AA 2024-T3 with 2-mercaptobenzothiazole (2-MBT) loaded PMAA@CeO2 nanocontainers were evaluated with and without artificial scribes by electrochemical impedance spectroscopy (EIS). The results indicated that the epoxy coating containing the 2-MBT-loaded nanocontainers provided enhanced protection of the AA 2024-T3 substrate.

  16. Note: A heated-air curtain design using the Coanda effect to protect optical access windows in high-temperature, condensing, and corrosive stack environments

    NASA Astrophysics Data System (ADS)

    Williams, Gustavious Paul; Keenan, Thomas L.; Herning, James; Kimblin, Clare; DiBenedetto, John; Anthony, Glen

    2011-01-01

    We present an air knife design for creating a heated air curtain to protect optical infrared access windows in high-temperature, condensing, and corrosive stack environments. The design uses the Coanda effect to turn the air curtain and to attach the air curtain to the window surface. The design was tested and verified on our 24 m stack and used extensively over a 6 yr period on several release stacks. During testing and subsequent use no detrimental changes to access window materials have been noted. This design allows stack monitoring without significantly affecting the stack flow profile or chemical concentration.

  17. Note: A heated-air curtain design using the Coanda effect to protect optical access windows in high-temperature, condensing, and corrosive stack environments.

    PubMed

    Williams, Gustavious Paul; Keenan, Thomas L; Herning, James; Kimblin, Clare; DiBenedetto, John; Anthony, Glen

    2011-01-01

    We present an air knife design for creating a heated air curtain to protect optical infrared access windows in high-temperature, condensing, and corrosive stack environments. The design uses the Coanda effect to turn the air curtain and to attach the air curtain to the window surface. The design was tested and verified on our 24 m stack and used extensively over a 6 yr period on several release stacks. During testing and subsequent use no detrimental changes to access window materials have been noted. This design allows stack monitoring without significantly affecting the stack flow profile or chemical concentration.

  18. Coated Aluminized Film Resists Corrosion

    NASA Technical Reports Server (NTRS)

    Rockoff, H. J.

    1982-01-01

    Commercially available corrosion-protection coating allows less costly metals - aluminum in particular used in heat-reflecting films for thermal barriers. Previously, such films had to incorporate gold as reflective layer to withstand humidity, moisture, and salt spray without corroding. This protective coating prevents corrosion of metalized films during evironmental exposure yet remains flexible, thermally stable and clear.

  19. Corrosion behaviour of tinplate cans in contact with tomato purée and protective (inhibiting) substances.

    PubMed

    Nincević Grassino, A; Grabarić, Z; Pezzani, A; Squitieri, G; Fasanaro, G; Impembo, M

    2009-11-01

    The dissolution of iron and tin from tinplate cans filled with tomato purée (pH 4.34) and dioctyl sebacate oil (DOS), essential onion oil (EOO) or potassium nitrate was studied using atomic absorption spectroscopy (AAS), while nitrate was determined using high-performance liquid chromatography (HPLC). The maximum values found in cans were up to 284 mg kg(-1) for tin and 513 mg kg(-1) for iron at elevated storage temperature. Results indicated that the addition of EOO to tomato purée prevents the corrosion process in the case of tin, where concentrations were lowered from 223 to 28 mg kg(-1) for cans with DOS oil and EOO at 20 degrees C, respectively (inhibition rate of 87%). On the other hand, the presence of EOO enhanced the corrosion process for iron increasing the concentration from 15 to 46 mg kg(-1) during 7 months of storage, although this value did not exceed maximum permitted value (50 mg kg(-1)). In cans with tomato purée and potassium nitrate, dissolution of tin started after 30 (36 degrees C) and 60 (20 degrees C) days of storage as a consequence of nitrate action, which act as a corrosion accelerator. Since the addition of EOO improves the taste of canned tomato purée, its potential use as a corrosion inhibitor would be of interest.

  20. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

    2011-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

  1. Application of a quartz crystal microbalance to the study of copper corrosion in acid solution inhibited by triazole-iodide protective films

    SciTech Connect

    Jope, D.; Sell, J.; Pickering, H.W.; Weil, K.G.

    1995-07-01

    When one uses one side of a quartz crystal microbalance as the working electrode in electrochemical experiments, mass changes can be monitored continuously with a sensitivity of a few nanograms per square centimeter. In this study the working electrode consisted of electrolytically deposited copper, exposed to 0.1M sodium sulfate at pH 3, open to the atmosphere and in some cases containing H{sub 2}O{sub 2}. Upon addition of one of the inhibitors, benzotriazole (BTA), tolyltriazole (TTA), carboxy-benzotriazole (CBT), or these inhibitors plus potassium iodide, the rate of frequency change decreases markedly. After removal of the inhibitors from the corrosive medium by fast solution exchange there is a marked continuing protective effect of the inhibitor films in the cases of BTA + KI and TTA + KI with the latter being the most stable and protective of all of the films. The results were qualitatively the same in the more corrosive solution containing H{sub 2}O{sub 2}.

  2. Triboelectric Charging at the Nanostructured Solid/Liquid Interface for Area-Scalable Wave Energy Conversion and Its Use in Corrosion Protection.

    PubMed

    Zhao, Xue Jiao; Zhu, Guang; Fan, You Jun; Li, Hua Yang; Wang, Zhong Lin

    2015-07-28

    We report a flexible and area-scalable energy-harvesting technique for converting kinetic wave energy. Triboelectrification as a result of direct interaction between a dynamic wave and a large-area nanostructured solid surface produces an induced current among an array of electrodes. An integration method ensures that the induced current between any pair of electrodes can be constructively added up, which enables significant enhancement in output power and realizes area-scalable integration of electrode arrays. Internal and external factors that affect the electric output are comprehensively discussed. The produced electricity not only drives small electronics but also achieves effective impressed current cathodic protection. This type of thin-film-based device is a potentially practical solution of on-site sustained power supply at either coastal or off-shore sites wherever a dynamic wave is available. Potential applications include corrosion protection, pollution degradation, water desalination, and wireless sensing for marine surveillance.

  3. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  4. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2004-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  5. Inclusion compounds of dibenzylthiourea with hydroxypropylated-cyclodextrins for corrosion protection of carbon steel in acidic medium

    NASA Astrophysics Data System (ADS)

    de Souza, Thais M.; Cordeiro, Renata F. B.; Viana, Gil M.; Aguiar, Lucia C. S.; de Senna, Lilian F.; Malta, Luiz Fernando B.; D'Elia, Eliane

    2016-12-01

    In this work the complexation of the guest molecule (dibenzylthiourea-DBT) with α and β forms of hydroxypropylated cyclodextrins was evaluated in solution and in the solid state by different techniques. It was shown that the inclusion complexes were obtained and the aromatic moieties of DBT are points of interaction in the structure of the guest. The inhibitory action of these inclusion compounds in carbon steel corrosion in acidic medium was evaluated by polarization curves, electrochemical impedance diagrams and weight loss measurements. There is an enhancement of the inhibitory action against the carbon steel corrosion in HCl solution when the DBT was encapsulated in inclusion compounds whereas the alone hydroxypropylated cyclodextrins did not present an inhibitory effect. It was concluded that these inclusion compounds could be a good alternative to introduce molecules with low solubility in aqueous media and still increase their inhibitory action.

  6. Production of carbon nano-tubes via CCVD method and their corrosion protection performance in epoxy based coatings

    NASA Astrophysics Data System (ADS)

    Raza, M. A.; Ghauri, F. A.; Awan, M. S.; Farooq, A.; Ahmad, R.

    2016-08-01

    Good yield of carbon products was obtained by catalytic chemical vapor deposition (CCVD) technique using 100-500mg of ferrocene catalyst at temperature of 900 °C and acetylene flow rate of 150-200cc/min. The effects of amount of ferrocene, temperature and hydrocarbons precursors on the yield of carbon nanomaterial's was calculated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) andenergy- dispersive X-ray spectroscopy (EDS). Good yield of carbon nanomaterials primarily consisted of carbon nanotubes (CNTs) and carbon nanoparticles was obtained. CNTs obtained after purification were dispersed in epoxy resin to produce composite coatings which were coated on stainless steel 316L. The coated stainless steel samples’ corrosion behavior was studied using open circuit potential (OCP), cyclic polarization and electrochemical impedance spectroscopy (EIS) techniques. Results showed that epoxy coating containing 4 wt. % of CNTs offered improved corrosion resistance to stainless steel.

  7. Optimizing NiCr and FeCr HVOF Coating Structures for High Temperature Corrosion Protection Applications

    NASA Astrophysics Data System (ADS)

    Oksa, M.; Metsäjoki, J.

    2015-02-01

    In order to achieve a desired dense structure for coatings employed in high temperature corrosion conditions, thermal spray process optimization with diagnostic tools can be applied. In this study, NiCr (51Ni-46Cr-2Si-1Fe) and FeCr (Fe-19Cr-9W-7Nb-4Mo-5B-2C-2Si-1Mn) powders were sprayed with HVOFGF (gas-fueled) and HVOFLF (liquid-fueled) systems, and the spray processes were monitored with diagnostic tools, including SprayWatch for measuring the temperature and velocity of the spray stream, and in situ coating property (ICP measurement) for measuring the stress state. Various spray parameters were applied to attain the best coating characteristics for high temperature applications. Selected coatings were exposed to high temperature corrosion conditions both in laboratory and actual power plant. The coatings were analyzed by microscopic means and mechanical testing. The application of process-structure-properties-performance methodology with the process monitoring, analysis of the coating characteristics, and results of corrosion performance are presented in this paper.

  8. Superconducting linear actuator

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce; Hockney, Richard

    1993-01-01

    Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

  9. Protective coatings for intraocular wirelessly controlled microrobots for implantation: Corrosion, cell culture, and in vivo animal tests.

    PubMed

    Pokki, Juho; Ergeneman, Olgaç; Chatzipirpiridis, George; Lühmann, Tessa; Sort, Jordi; Pellicer, Eva; Pot, Simon A; Spiess, Bernhard M; Pané, Salvador; Nelson, Bradley J

    2016-01-24

    Diseases in the ocular posterior segment are a leading cause of blindness. The surgical skills required to treat them are at the limits of human manipulation ability, and involve the risk of permanent retinal damage. Instrument tethering and design limit accessibility within the eye. Wireless microrobots suturelessly injected into the posterior segment, steered using magnetic manipulation are proposed for procedures involving implantation. Biocompatibility is a prerequisite for these procedures. This article investigates the use of polypyrrole- and gold-coated cobalt-nickel microrobots. While gold has been used in ocular implants, no ocular implantation involving polypyrrole is reported, despite its well-established biocompatibility properties. Coated and uncoated microrobots were investigated for their corrosion properties, and solutions that had contained coated and uncoated microrobots for one week were tested for cytotoxicity by monitoring NIH3T3 cell viability. None of the microrobots showed significant corrosion currents and corrosion potentials were as expected in relation to the intrinsic nobility of the materials. NIH3T3 cell viability was not affected by the release medium, in which coated/uncoated microrobots were stored. In vivo tests inside rabbit eyes were performed using coated microrobots. There were no significant inflammatory responses during the first week after injection. An inflammatory response detected after 2 weeks was likely due to a lack of longer-duration biocompatibility. The results provide valuable information for those who work on implant technology and biocompatibility. Coated microrobots have the potential to facilitate a new generation of surgical treatments, diagnostics and drug-delivery techniques, when implantation in the ocular posterior segment will be possible. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  10. Corrosion and protection of heterogeneous cast Al-Si (356) and Al-Si-Cu-Fe (380) alloys by chromate adn cerium inhibitors

    NASA Astrophysics Data System (ADS)

    Jain, Syadwad

    In this study, the localized corrosion and conversion coating on cast alloys 356 (Al-7.0Si-0.3Mg) and 380 (Al-8.5Si-3.5Cu-1.6Fe) were characterized. The intermetallic phases presence in the permanent mold cast alloy 356 are primary-Si, Al5FeSi, Al8Si6Mg3Fe and Mg2Si. The die cast alloy 380 is rich in Cu and Fe elements. These alloying elements result in formation of the intermetallic phases Al 5FeSi, Al2Cu and Al(FeCuCr) along with primary-Si. The Cu- and Fe-rich IMPS are cathodic with respect to the matrix phase and strongly govern the corrosion behavior of the two cast alloys in an aggressive environment due to formation of local electrochemical cell in their vicinity. Results have shown that corrosion behavior of permanent mould cast alloy 356 is significantly better than the die cast aluminum alloy 380, primarily due to high content of Cu- and Fe-rich phases such as Al2Cu and Al 5FeSi in the latter. The IMPS also alter the protection mechanism of the cast alloys in the presence of inhibitors in an environment. The presence of chromate in the solution results in reduced cathodic activity on all the phases. Chromate provides some anodic inhibition by increasing pitting potentials and altering corrosion potentials for the phases. Results have shown that performance of CCC was much better on 356 than on 380, primarily due to inhomogeneous and incomplete coating deposition on Cu- and Fe- phases present in alloy 380. XPS and Raman were used to characterize coating deposition on intermetallics. Results show evidence of cyanide complex formation on the intermetallic phases. The presence of this complex is speculated to locally suppress CCC formation. Formation and breakdown of cerium conversion coatings on 356 and 380 was also analyzed. Results showed that deposition of cerium hydroxide started with heavy precipitation on intermetallic particles with the coatings growing outwards onto the matrix. Electrochemical analysis of synthesized intermetallics compounds in the

  11. Virtual Instrumentation Corrosion Controller for Natural Gas Pipelines

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, J.; Agnihotri, G.; Deshpande, D. M.

    2012-12-01

    Corrosion is an electrochemical process. Corrosion in natural gas (methane) pipelines leads to leakages. Corrosion occurs when anode and cathode are connected through electrolyte. Rate of corrosion in metallic pipeline can be controlled by impressing current to it and thereby making it to act as cathode of corrosion cell. Technologically advanced and energy efficient corrosion controller is required to protect natural gas pipelines. Proposed virtual instrumentation (VI) based corrosion controller precisely controls the external corrosion in underground metallic pipelines, enhances its life and ensures safety. Designing and development of proportional-integral-differential (PID) corrosion controller using VI (LabVIEW) is carried out. When the designed controller is deployed at field, it maintains the pipe to soil potential (PSP) within safe operating limit and not entering into over/under protection zone. Horizontal deployment of this technique can be done to protect all metallic structure, oil pipelines, which need corrosion protection.

  12. Synthesis and application of hybrid polymer composites based on silver nanoparticles as corrosion protection for line pipe steel.

    PubMed

    Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdurrahman O

    2014-05-16

    A facile method was developed to synthesize in high yield dispersed silver nanoparticles (AgNPs) with small particle sizes of less than 10 nm. Silver nitrate was reduced to silver nanoparticles by p-chloroaniline in the presence of polyoxyethylene maleate 4-nonyl-2-propylene-phenol (NMA) as a stabilizer. The produced AgNPs were used to prepare hybrid polymer based on N-isopropylacrylamide (NIPAm), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N,N-methylenebisacrylamide (MBA) and potassium persulfate (KPS) using a semi-batch solution polymerization method. The prepared AgNPs and hybrid polymer were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM). The corrosion inhibition activity of the AgNPs and hybrid polymer towards steel corrosion in the presence of hydrochloric acid has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that the AgNPs and hybrid polymer acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  13. Reline 33 year old kettle for more corrosive process at about 1/3 cost of new unit: lightweight foamed glass block protects corroded cast iron cover

    SciTech Connect

    Not Available

    1982-06-01

    This article presents a solution to a chemical plant's need for a lining material to reline a 33 year old kettle that would be resistant to attack by aqueous bromine and hydrochloric, nitrous, and bromic acid. The solution was to use an elastomeric polyisobutylene sheeting as a primary lining for the kettle. The problem was also solved by using a light weight foamed glass block which protected the corroded cast iron dome cover for the kettle. Installation of the two-step lining for the kettle and cover by Chemsteel Construction Company of New Kensington, PA was completed in 5 weeks. The cost was about 1/3 as much as fabricating, installing, and lining a new steel 5000 gal vessel. The kettle has been in service about 12 months and the acid brick/polyisobutylene membrance liner shows no signs of damage from the highly corrosive chemicals and elevated temperatures required for the process change.

  14. Micromachined electrostatic vertical actuator

    DOEpatents

    Lee, Abraham P.; Sommargren, Gary E.; McConaghy, Charles F.; Krulevitch, Peter A.

    1999-10-19

    A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

  15. Corrosion beneath disbonded pipeline coatings

    SciTech Connect

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

    1997-04-01

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

  16. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  17. Corrosion beneath disbonded coatings: A review

    SciTech Connect

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

    1996-12-01

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

  18. Computerized system for corrosion control

    SciTech Connect

    Hall, C. )

    1991-10-01

    This paper reports that computerization of basic corrosion measurements to provide record-keeping and graphical output has been used by pipeline companies over the lst decade. Northwest Pipeline Corp. has embarked on an ambition project to expand well beyond the scope of standard computer record-keeping by integrating data analysis and management with computer-aided advanced corrosion engineering practices. Most maturing pipeline systems require immense capital and maintenance expenditures to maintain regulatory levels of cathodic protection consistent with traditional corrosion control methods. Major pipeline coating rehabilitation programs and the installation of numerous anode-bed systems will continue in the absence of sophisticated computer-aided corrosion control methods.

  19. Corrosion `98: 53. annual conference and exposition, proceedings

    SciTech Connect

    1998-12-31

    This conference was divided into the following sections: Corrosion in Gas Treating; Problems and Solutions in Commercial Building Water Systems; Green Corrosion/Scale Inhibitors; Atmospheric Corrosion; AIRPOL Update/98; Rubber Lining--Answers to Many Problems; Interference Problems; Environmental Assisted Cracking: Fundamental Research and Industrial Applications; Corrosion in Nuclear Systems; New Developments in Scale and Deposit Control; Corrosion and Corrosion Protection in the Transportation Industries; What`s All the Noise About--Electrochemical That Is; Refining Industry Corrosion; Corrosion Problems in Military Hardware: Case Histories, Fixes and Lessons Learned; Cathodic Protection Test Methods and Instrumentation for Underground and On-grade Pipelines and Tanks; Recent Developments in Volatile Corrosion Inhibitors; Corrosion in Supercritical Fluids; Microbiologically Influenced Corrosion; Advances in Understanding and Controlling CO{sub 2} Corrosion; Managing Corrosion with Plastics; Material Developments for Use in Exploration and Production Environments; Corrosion in Cold Regions; The Effect of Downsizing and Outsourcing on Cooling System Monitoring and Control Practices; New Developments in Mechanical and Chemical Industrial Cleaning; Mineral Scale Deposit Control in Oilfield Related Operations; Biocides in Cooling Water; Corrosion and Corrosion Control of Reinforced Concrete Structures; Materials Performance for Fossil Energy Conversion Systems; Marine corrosion; Thermal Spray--Coating and Corrosion Control; Flow Effects on Corrosion in Oil and Gas Production; Corrosion Measurement Technologies; Internal Pipeline Monitoring--Corrosion Monitoring, Intelligent Pigging and Leak Detection; Cathodic Protection in Natural Waters; Corrosion in Radioactive Liquid Waste Systems; On-line Hydrogen Permeation Monitoring Equipment and Techniques, State of the Art; Water Reuse and Recovery; Performance of Materials in High Temperature Environments; Advances in Motor

  20. Self-sealing anodization approach to enhance micro-Vickers hardness and corrosion protection of a die cast Al alloy

    NASA Astrophysics Data System (ADS)

    Lee, Chulho; Oh, Kiseok; Lee, Dongeun; Kim, Yelim; Yoon, Hyungsop; Park, Dong-Wha; Gab Kim, Moon; Lee, Kiyoung; Choi, Jinsub

    2017-04-01

    Die cast, high-Si content ADC12 Al alloy samples were successfully anodized without surface cracks. This was accomplished with a 0.3 M sulfuric acid electrolyte with a high concentration of sodium aluminate. During anodization, the AlO2- anions were attracted to the positively-charged Al substrate and deposited in the cracks formed by un-oxidized Si islands within the ADC12. Anodic films prepared in electrolytes with a high concentration of AlO2- drastically enhanced surface morphology, thickness uniformity, Vickers hardness, and corrosion behavior in comparison with anodic film prepared without AlO2- concentration. The simultaneous sealing mechanism by AlO2- anions during anodization is reported in detail.

  1. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  2. Measurement and mitigation of corrosion on self-contained fluid filled (SCFF) submarine circuits for New York Power Authority: Volume 2 -- Stray electrical current measurements and preliminary design of the cathodic protection system. Final report

    SciTech Connect

    1998-10-01

    In 1987, the New York Power Authority (NYPA) installed a 345-kV submarine cable circuit across Long Island Sound between substations at Davenport Neck and Hempstead Harbor. During design and installation of the cable circuit, utility and cable manufacturers engineers identified corrosion as a possible problem for the cable system. They considered such effects in the cable design and discussed preliminary requirements for a cathodic protection system on Long Island Sound circuit. EPRI cosponsored this review of the corrosion effects with NYPA and Empire State Electric Energy Research Corp. (ESEERCO). Volume 1 of this report discusses the results from an in-depth evaluation of the self-contained fluid-filled (SCFF) cable construction materials and their susceptibility to corrosion. Volume 2 provides extended stray current field measurements and a preliminary design for a cathodic protection system to ensure cable service reliability. This study provides a blueprint for East or West Coast utilities evaluating site-specific corrosion processes and cable circuit protection methods suitable for underwater environments.

  3. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  4. 49 CFR 193.2631 - Internal corrosion control.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Internal corrosion control. 193.2631 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2631 Internal corrosion control. Each component that is subject to internal corrosive attack must be protected from internal corrosion by—...

  5. 49 CFR 193.2631 - Internal corrosion control.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Internal corrosion control. 193.2631 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2631 Internal corrosion control. Each component that is subject to internal corrosive attack must be protected from internal corrosion by—...

  6. 49 CFR 193.2631 - Internal corrosion control.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Internal corrosion control. 193.2631 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2631 Internal corrosion control. Each component that is subject to internal corrosive attack must be protected from internal corrosion by—...

  7. 49 CFR 193.2631 - Internal corrosion control.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Internal corrosion control. 193.2631 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2631 Internal corrosion control. Each component that is subject to internal corrosive attack must be protected from internal corrosion by—...

  8. U.S. Coast Guard Corrosion Program Office

    DTIC Science & Technology

    2014-11-20

    gr am O ff ic e USCG Aviation Corrosion Program ASETSDefense November 20, 2014 CWO Randy Langley USCG Aviation Corrosion Program Manager...Future Projects for the Corrosion Program Distribution Statement A: Approved for public release. Distribution is unlimited. ASETSDefense...insides of tubes and crevices. • Improved quality, coverage, and adherence will enhance corrosion protection. • Tank can coat parts up to 36

  9. Underground corrosion control

    SciTech Connect

    Not Available

    1993-01-01

    Corrosion of underground metallic structures continues to be a crucial concern within society and the engineering community. Costs associated with corrosion losses are staggering. Indirect costs associated with environmental damage as well as loss of public confidence has in many cases out-stripped direct costs for facility repair and replacement. NACE Group Committee T-10, responsible for the study and advancement of technology necessary for engineering solutions for underground corrosion problems, is divided into five key unit committees as follows: cathodic protection; interference problems; electric power and communications; protective coating systems; and internal corrosion of pipelines. The papers presented in this publication reflect the most recent developments in field practice in all five areas. Cathodic protection criteria, protection of pipelines, tanks and pilings, test methods, transit systems investigations, power and communication cables, and compliance with regulations are addressed. Interference testing, refinery problems, methods of safely mitigating the effects of induced AC on pipelines, and experience with alternate engineering materials such as prestressed concrete cylinder pipe and ductile iron pipe are included. All 37 papers have been processed separately for inclusion on the data base.

  10. Self-actuating reactor shutdown system

    DOEpatents

    Barrus, Donald M.; Brummond, Willian A; Peterson, Leslie F.

    1988-01-01

    A control system for the automatic or self-actuated shutdown or "scram" of a nuclear reactor. The system is capable of initiating scram insertion by a signal from the plant protection system or by independent action directly sensing reactor conditions of low-flow or over-power. Self-actuation due to a loss of reactor coolant flow results from a decrease of pressure differential between the upper and lower ends of an absorber element. When the force due to this differential falls below the weight of the element, the element will fall by gravitational force to scram the reactor. Self-actuation due to high neutron flux is accomplished via a valve controlled by an electromagnet and a thermionic diode. In a reactor over-power, the diode will be heated to a change of state causing the electromagnet to be shorted thereby actuating the valve which provides the changed flow and pressure conditions required for scramming the absorber element.

  11. Corrosion protection of silver-based telescope mirrors using evaporated anti-oxidation overlayers and aluminum oxide films by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Fryauf, David M.; Phillips, Andrew C.; Kobayashi, Nobuhiko P.

    2016-09-01

    An urgent demand remains in astronomy for high-reflectivity silver mirrors that can withstand years of exposure in observatory environments. The University of California Observatories Astronomical Coatings Lab has undertaken development of protected silver coatings suitable for telescope mirrors that maintain high reflectivity at wavelengths from 340 nm through the mid-infrared spectrum. We present results on superior protective layers of transparent dielectrics produced by evaporation and atomic layer deposition. Several novel coating recipes have been developed with ion-assisted electron beam deposition (IAEBD) of various fluorides, oxides, and nitrides in combination with conformal layers of aluminum oxide (AlOx) deposited by ALD using trimethylaluminum as a metal precursor and water vapor as a reactant. Extending on our previous results demonstrating the superior durability of ALD-based AlOx top barrier layers over conventionally-deposited AlOx, this work investigates the effects on mirror barrier durability comparing different anti-oxidation materials on Ag with an identical AlOx top barrier layer deposited by ALD. Samples of coating recipes with different anti-oxidation layers undergo aggressive environmental testing, including high temperature/high humidity (HTHH), in which samples are exposed to an environment of 80% humidity at 80°C for ten days in a simple test set-up. While most samples show fairly successful endurance after HTHH testing, visible results suggest that MgAl2O4, Al2O3, and AlN anti-oxidation layers offer enhanced robust protection against chemical corrosion and moisture in an accelerated aging environment, which is attributed to superior adhesion and intermolecular bonding between the Al-based anti-oxidation layers and the AlOx top barrier layer. Mirror samples are further characterized by reflectivity/absorption before and after deposition of oxide coatings. We also show that the performance of the ALD-AlOx barrier layer depends in part

  12. Moisture barrier and chemical corrosion protection of silver-based telescope mirrors using aluminum oxide films by plasma-enhanced atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Fryauf, David M.; Phillips, Andrew C.; Kobayashi, Nobuhiko P.

    2013-09-01

    An urgent demand remains in astronomy for high-reflectivity silver mirrors that can withstand years of exposure in observatory environments. The University of California Observatories Astronomical Coatings Lab has undertaken development of protected silver coatings suitable for telescope mirrors that maintain high reflectivity at wavelengths from 340 nm through the mid-infrared spectrum. We present initial results of an investigation into whether plasma-enhanced atomic layer deposition (PEALD) can produce superior protective layers of transparent dielectrics. Several novel coating recipes have been developed with ion-assisted electron beam deposition (IAEBD) of materials including yttrium fluoride, and oxides of yttrium, hafnium, and titanium. Samples of these mirror coatings were covered with conformal layers of aluminum oxide (AlOx) deposited by PEALD using trimethylaluminum as a metal precursor and oxygen as an oxidant gas activated by remote plasma. Samples of coating recipes with and without PEALD oxide undergo aggressive environmental testing, including high temperature/high humidity (HTHH), in which samples were exposed to an environment of 80% humidity at 80°C for ten days in a simple test set-up. HTHH testing show visible results suggesting that the PEALD oxide offers enhanced robust protection against chemical corrosion and moisture from an accelerated aging environment. Mirror samples are further characterized by reflectivity/absorption and atomic force microscopy before and after deposition of oxide coatings. AlOx is suitable for many applications and has been the initial material choice for this study, although we also tried TiOx and HfOx. Further experimentation based on these initial results is on-going.

  13. MEMS fluidic actuator

    DOEpatents

    Kholwadwala, Deepesh K.; Johnston, Gabriel A.; Rohrer, Brandon R.; Galambos, Paul C.; Okandan, Murat

    2007-07-24

    The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

  14. Effective Actuation: High Bandwidth Actuators and Actuator Scaling Laws

    DTIC Science & Technology

    2007-11-02

    5c. PROGRAM ELEMENT NUMBER I-ioh Bandwidth Actiintorv and Actuator 9clinp Iaw-, 65502F 6. AUTHOR(S) 5d. PROJECT NUMBER A. B. Cain, G. R. Raman , and E...of possible applications include the high frequency excitation for supprc~sion of flow induced resonance in weapons bay cavities (see Raman et al...systems. Adaptive high bandwidth actuators are required to adapt to changes in flow speed and conditions during flight. Raman et al. (2000) and Stanek et

  15. Hydraulic Actuator Project

    DTIC Science & Technology

    2003-11-01

    Hydraulic Actuator Project Stakeholder meeting held 7- 8 October in Los Angeles; 58 attendees representing aircraft and actuator OEMs, seal...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Research Laboratory,4555 Overlook Ave., SW ,Washington,DC,20375 8 . PERFORMING ORGANIZATION REPORT...unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8 -98) Prescribed by ANSI Std Z39-18 Actuator JTP: Coupon Testing Substrate

  16. Electrostatically Driven Nanoballoon Actuator.

    PubMed

    Barzegar, Hamid Reza; Yan, Aiming; Coh, Sinisa; Gracia-Espino, Eduardo; Dunn, Gabriel; Wågberg, Thomas; Louie, Steven G; Cohen, Marvin L; Zettl, Alex

    2016-11-09

    We demonstrate an inflatable nanoballoon actuator based on geometrical transitions between the inflated (cylindrical) and collapsed (flattened) forms of a carbon nanotube. In situ transmission electron microscopy experiments employing a nanoelectromechanical manipulator show that a collapsed carbon nanotube can be reinflated by electrically charging the nanotube, thus realizing an electrostatically driven nanoballoon actuator. We find that the tube actuator can be reliably cycled with only modest control voltages (few volts) with no apparent wear or fatigue. A complementary theoretical analysis identifies critical parameters for nanotube nanoballoon actuation.

  17. Improved Electrohydraulic Linear Actuators

    NASA Technical Reports Server (NTRS)

    Hamtil, James

    2004-01-01

    A product line of improved electrohydraulic linear actuators has been developed. These actuators are designed especially for use in actuating valves in rocket-engine test facilities. They are also adaptable to many industrial uses, such as steam turbines, process control valves, dampers, motion control, etc. The advantageous features of the improved electrohydraulic linear actuators are best described with respect to shortcomings of prior electrohydraulic linear actuators that the improved ones are intended to supplant. The flow of hydraulic fluid to the two ports of the actuator cylinder is controlled by a servo valve that is controlled by a signal from a servo amplifier that, in turn, receives an analog position-command signal (a current having a value between 4 and 20 mA) from a supervisory control system of the facility. As the position command changes, the servo valve shifts, causing a greater flow of hydraulic fluid to one side of the cylinder and thereby causing the actuator piston to move to extend or retract a piston rod from the actuator body. A linear variable differential transformer (LVDT) directly linked to the piston provides a position-feedback signal, which is compared with the position-command signal in the servo amplifier. When the position-feedback and position-command signals match, the servo valve moves to its null position, in which it holds the actuator piston at a steady position.

  18. Drywell corrosion stopped at Oyster Creek

    SciTech Connect

    Lipford, B.L. ); Flynn, J.C.

    1993-11-01

    This article describes the detection of corrosion on the drywell containment vessel of Oyster Creek Nuclear Plant and the application of a protective coating to repair the drywell. The topics of the article include drywell design features, identification of the problem, initial action, drywell corrosion, failure of cathodic protection, long-term repair, and repair results.

  19. Corrosion Engineering.

    ERIC Educational Resources Information Center

    White, Charles V.

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

  20. Fireside Corrosion

    SciTech Connect

    Holcomb, Gordon

    2011-07-14

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

  1. Corrosion sensor

    DOEpatents

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

    1994-04-26

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

  2. Corrosion sensor

    DOEpatents

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

    1994-01-01

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

  3. Underground pipeline corrosion control

    SciTech Connect

    Gundry, R.D.

    1988-04-01

    In the past few years, the pipeline corrosion control industry has been shaken by several catastrophic pipeline failures attributed to corrosion. Reports of corrosion-related failures seem to be on the rise, and this has caused the industry to reassess the criteria for cathodic protection and the correct application of the criteria. The US Congress and many state legislatures are also asking questions about pipeline safety. Several pieces of legislation are proposed to improve pipeline safety. NACE Task Group T-10-1 is in the process of revising Standard RP0169. Field data have been solicited from industry and are being analyzed. The committee has reviewed an extensive compilation of articles written over the last 50 years to evaluate the existing document. The committee is also awaiting the issuance of an Interim Report from the American Gas Association on the effectiveness of the criteria. The report is to present data obtained from several field test sites from around the country.

  4. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    NASA Astrophysics Data System (ADS)

    Fazullin, D. D.; Mavrin, G. V.; Shaikhiev, I. G.

    2016-06-01

    The article describes the corrosion test of steel of the brand 20 in the stratal water. To increase corrosion resistance as a corrosion inhibitor the concentrate waste emulsion of the mark "Incam- 1" was provided. The article presents studies of the corrosion rate with different dosages of corrosion inhibitor in the stratal water. Based on these research results are revealed that the degree of protection of steel is 27% at a dosage of 3.8 g / dm3.

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

    SciTech Connect

    K.G. Mon

    2004-10-01

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

  6. Three d.o.f. Robotic Wrist Actuator Redesign

    NASA Technical Reports Server (NTRS)

    Bonner, Tom; Tamasi, Gabor

    1997-01-01

    This paper describes the efforts to redesign, fabricate, assemble and test the wrist actuators on the Automated Tile Processing System (ATPS). The ATPS is a robotic system being developed at Kennedy Space Center to inspect and rewaterproof thermal protection tiles on the space shuttle orbiter prior to launch. The objective of the redesign was to eliminate backlash and provide adequate pitch and yaw actuator force. The wrist actuators have been successfully redesigned, fabricated, tested, and installed. The redesigned wrist actuators meet or exceed all design requirements. The wrist has been reinstalled on the tile processing robot and will be further evaluated during operational testing of the system.

  7. Refractory Materials for Flame Deflector Protection System Corrosion Control: Similar Industries and/or Launch Facilities Survey

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Coffman, Brekke E.; Sampson, Jeffrey W.; Kolody, Mark R.; Curran, Jerome P.; Perusich, Stephen A.; Trejo, David; Whitten, Mary C.; Zidek, Jason

    2009-01-01

    A trade study and litera ture survey of refractory materials (fi rebrick. refractory concrete. and si licone and epoxy ablatives) were conducted to identify candidate replacement materials for Launch Complexes 39A and 398 at Kennedy Space Center (KSC). In addition, site vis its and in terviews with industry expens and vendors of refractory materials were conducted. As a result of the si te visits and interviews, several products were identified for launch applications. Firebrick is costly to procure and install and was not used in the si tes studied. Refractory concrete is gunnable. adheres well. and costs less 10 install. Martyte. a ceramic fi lled epoxy. can protect structural stccl but is costly. difficullto apply. and incompatible with silicone ablatives. Havanex, a phenolic ablative material, is easy to apply but is costly and requires frequent replacement. Silicone ablatives are ineJ[pensive, easy to apply. and perl'onn well outside of direct rocket impingement areas. but refractory concrete and epoxy ablatives provide better protection against direcl rocket exhaust. None of the prodUCIS in this trade study can be considered a panacea for these KSC launch complexes. but the refractory products. individually or in combination, may be considered for use provided the appropriate testing requirements and specifications are met.

  8. Self-actuated device

    DOEpatents

    Hecht, Samuel L.

    1984-01-01

    A self-actuated device, of particular use as a valve or an orifice for nuclear reactor fuel and blanket assemblies, in which a gas produced by a neutron induced nuclear reaction gradually accumulates as a function of neutron fluence. The gas pressure increase occasioned by such accumulation of gas is used to actuate the device.

  9. Remotely controllable actuating device

    NASA Technical Reports Server (NTRS)

    McKillip, Jr., Robert M. (Inventor)

    1998-01-01

    An actuating device can change a position of an active member that remains in substantially the same position in the absence of a force of a predetermined magnitude on the active member. The actuating device comprises a shape-memory alloy actuating member for exerting a force when actuated by changing the temperature thereof, which shape-memory alloy actuating member has a portion for connection to the active member for exerting thereon a force having a magnitude at least as large as the predetermined magnitude for moving the active member to a desired position. Actuation circuitry is provided for actuating the shape-memory alloy actuating member by changing the temperature thereof only for the time necessary to move the active member to the desired position. The invention is particularly useful for changing the position of a camber-adjusting tab on a helicopter rotor blade by using two shape-memory alloy members that can act against each other to adjust dynamic properties of the rotor blade as it is rotating.

  10. Massively Redundant Electromechanical Actuators

    DTIC Science & Technology

    2014-08-30

    date of determination). DoD Controlling Office is (insert controlling DoD office). "Massively Redundant Electromechanical Actuators" August... electromechanical systems) processes are used to manufacture reliable and reproducible stators and sliders for the actuators. These processes include

  11. NASA's Corrosion Technology Laboratory at the Kennedy Space Center: Anticipating, Managing, and Preventing Corrosion

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina

    2015-01-01

    The marine environment at NASAs Kennedy Space Center (KSC) has been documented by ASM International (formerly American Society for Metals) as the most corrosive in North America. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pads were rendered even more severe by the highly corrosive hydrochloric acid (HCl) generated by the solid rocket boosters (SRBs). Numerous failures at the launch pads are caused by corrosion. The structural integrity of ground infrastructure and flight hardware is critical to the success, safety, cost, and sustainability of space missions. NASA has over fifty years of experience dealing with unexpected failures caused by corrosion and has developed expertise in corrosion control in the launch and other environments. The Corrosion Technology Laboratory at KSC evolved, from what started as an atmospheric exposure test site near NASAs launch pads, into a capability that provides technical innovations and engineering services in all areas of corrosion for NASA, external partners, and customers.This paper provides a chronological overview of NASAs role in anticipating, managing, and preventing corrosion in highly corrosive environments. One important challenge in managing and preventing corrosion involves the detrimental impact on humans and the environment of what have been very effective corrosion control strategies. This challenge has motivated the development of new corrosion control technologies that are more effective and environmentally friendly. Strategies for improved corrosion protection and durability can have a huge impact on the economic sustainability of human spaceflight operations.

  12. Fast electrochemical actuator

    NASA Astrophysics Data System (ADS)

    Uvarov, I. V.; Postnikov, A. V.; Svetovoy, V. B.

    2016-03-01

    Lack of fast and strong microactuators is a well-recognized problem in MEMS community. Electrochemical actuators can develop high pressure but they are notoriously slow. Water electrolysis produced by short voltage pulses of alternating polarity can overcome the problem of slow gas termination. Here we demonstrate an actuation regime, for which the gas pressure is relaxed just for 10 μs or so. The actuator consists of a microchamber filled with the electrolyte and covered with a flexible membrane. The membrane bends outward when the pressure in the chamber increases. Fast termination of gas and high pressure developed in the chamber are related to a high density of nanobubbles in the chamber. The physical processes happening in the chamber are discussed so as problems that have to be resolved for practical applications of this actuation regime. The actuator can be used as a driving engine for microfluidics.

  13. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water...

  14. Diffusion Coatings as Corrosion Inhibitors

    NASA Astrophysics Data System (ADS)

    Ivanov, Radoslav; Ignatova-Ivanova, Tsveteslava

    2016-03-01

    Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of B2O3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH4)2.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of B2O3), and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

  15. Corrosion-Resistant Roof with Integrated Photovoltaic Power System

    DTIC Science & Technology

    2014-02-01

    system as attached to a metal-panel roof that is protected with a high-performance, corrosion -resistant coating . 1.3 Approach A severely corroded...fluoride (PVF) and polyvinylidene fluoride (PVDF) can pro- vide excellent corrosion protection in corrosive environments such as KMC. Sustainable...systems on the corrosion resistance of coated metal roofing systems is not known. Potential corro- sion mechanisms include moisture trapped between the

  16. CORROSION OF HIGH-TEMPERATURE ALLOYS

    SciTech Connect

    John P. Hurley; John P. Kay

    1999-10-01

    Five alloys were tested in the presence of water vapor and water vapor with HCl for 1000 hours using simulated combustion gas. Samples were removed at intervals during each test and measured for determination of corrosion rates. One sample of each alloy was examined with a SEM after the completion of each test. Cumulative corrosion depths were similar for the superstainless alloys. Corrosion for Alloy TP310 roughly doubled. Corrosion for the enhanced stainless alloys changed dramatically with the addition of chlorine. Corrosion for Alloy RA85H increased threefold, whereas Alloy TP347HFG showed an eightfold increase. SEM examination of the alloys revealed that water vapor alone allowed the formation of chromium oxide protective layers on the superstainless alloys. The enhanced stainless alloys underwent more corrosion due to greater attack of sulfur. Iron-rich oxide layers were more likely to form, which do not provide protection from further corrosion. The addition of chlorine further increased the corrosion because of its ability to diffuse through the oxide layers and react with iron. This resulted in a broken, discontinuous, and loose oxide layer that offered less protection. Niobium, although added to aid in creep strength, was found to be detrimental to corrosion resistance. The niobium tended to be concentrated in nodules and was easily attacked through sulfidation, providing conduits for further corrosion deep into the alloy. The alloys that displayed the best corrosion resistance were those which could produce chromium oxide protective layers. The predicted microstructure of all alloys except Alloy HR3C is the same and provided no further information relating to corrosion resistance. No correlation can be found relating corrosion resistance to the quantity of minor austenite-or ferrite-stabilizing elements. Also, there does not appear to be a correlation between corrosion resistance and the Cr:Ni ratio of the alloy. These alloys were tested for their

  17. Cryogenic Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

    2009-01-01

    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  18. 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.

  19. Synthesize and characterization of a novel anticorrosive cobalt ferrite nanoparticles dispersed in silica matrix (CoFe2O4-SiO2) to improve the corrosion protection performance of epoxy coating

    NASA Astrophysics Data System (ADS)

    Gharagozlou, M.; Ramezanzadeh, B.; Baradaran, Z.

    2016-07-01

    This study aimed at studying the effect of an anticorrosive nickel ferrite nanoparticle dispersed in silica matrix (NiFe2O4-SiO2) on the corrosion protection properties of steel substrate. NiFe2O4 and NiFe2O4-SiO2 nanopigments were synthesized and then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). Then, 1 wt.% of nanopigments was dispersed in an epoxy coating and the resultant nanocomposites were applied on the steel substrates. The corrosion inhibition effects of nanopigments were tested by an electrochemical impedance spectroscopy (EIS) and salt spray test. Results revealed that dispersing nickel ferrite nanoparticles in a silica matrix (NiFe2O4-SiO2) resulted in the enhancement of the nanopigment dispersion in the epoxy coating matrix. Inclusion of 1 wt.% of NiFe2O4-SiO2 nanopigment into the epoxy coating enhanced its corrosion protection properties before and after scratching.

  20. Corrosion resistant coating

    DOEpatents

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

    1997-01-01

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

  1. Corrosion resistant coating

    DOEpatents

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

    1997-08-19

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

  2. Corrosive resistant heat exchanger

    DOEpatents

    Richlen, Scott L.

    1989-01-01

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

  3. Corrosion Behavior of Steel Fibrous Concrete

    DTIC Science & Technology

    1977-05-01

    Crvtaiue wi ,rerse sido it necessaty m’d Identify by block number) steel fibrous concrete corrosion cracked fibrous concrete 20 ABST RACT (Continue...dissolved gas in liq- Although chloride ions affect the rate of steel corro- uids. sion in concrete , corrosion can occur without them. Verbeck has...repcrted that steel subjected to a concrete Corrosion of steel will not occur without water. Not environment normally develops a protective oxide film

  4. Magnetically Actuated Seal

    NASA Technical Reports Server (NTRS)

    Pinera, Alex

    2013-01-01

    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  5. Rotary Series Elastic Actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)

    2013-01-01

    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  6. Rotary series elastic actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)

    2012-01-01

    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  7. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III

    1994-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The linear proof mass actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (mass, upper housing, lower housing, and center support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operating testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  8. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, S. E., III

    1995-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The Linear Proof Mass Actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (Mass, Upper Housing, Lower Housing, and Center Support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operational testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  9. Muscle Motion Solenoid Actuator

    NASA Astrophysics Data System (ADS)

    Obata, Shuji

    It is one of our dreams to mechanically recover the lost body for damaged humans. Realistic humanoid robots composed of such machines require muscle motion actuators controlled by all pulling actions. Particularly, antagonistic pairs of bi-articular muscles are very important in animal's motions. A system of actuators is proposed using the electromagnetic force of the solenoids with the abilities of the stroke length over 10 cm and the strength about 20 N, which are needed to move the real human arm. The devised actuators are based on developments of recent modern electro-magnetic materials, where old time materials can not give such possibility. Composite actuators are controlled by a high ability computer and software making genuine motions.

  10. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  11. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  12. Inertial Linear Actuators

    NASA Technical Reports Server (NTRS)

    Laughlin, Darren

    1995-01-01

    Inertial linear actuators developed to suppress residual accelerations of nominally stationary or steadily moving platforms. Function like long-stroke version of voice coil in conventional loudspeaker, with superimposed linear variable-differential transformer. Basic concept also applicable to suppression of vibrations of terrestrial platforms. For example, laboratory table equipped with such actuators plus suitable vibration sensors and control circuits made to vibrate much less in presence of seismic, vehicular, and other environmental vibrational disturbances.

  13. Combustion powered linear actuator

    DOEpatents

    Fischer, Gary J.

    2007-09-04

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  14. Laser Initiated Actuator study

    SciTech Connect

    Watson, B.

    1991-06-27

    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  15. Compact electrostatic comb actuator

    DOEpatents

    Rodgers, M. Steven; Burg, Michael S.; Jensen, Brian D.; Miller, Samuel L.; Barnes, Stephen M.

    2000-01-01

    A compact electrostatic comb actuator is disclosed for microelectromechanical (MEM) applications. The actuator is based upon a plurality of meshed electrostatic combs, some of which are stationary and others of which are moveable. One or more restoring springs are fabricated within an outline of the electrostatic combs (i.e. superposed with the moveable electrostatic combs) to considerably reduce the space required for the actuator. Additionally, a truss structure is provided to support the moveable electrostatic combs and prevent bending or distortion of these combs due to unbalanced electrostatic forces or external loading. The truss structure formed about the moveable electrostatic combs allows the spacing between the interdigitated fingers of the combs to be reduced to about one micron or less, thereby substantially increasing the number of active fingers which can be provided in a given area. Finally, electrostatic shields can be used in the actuator to substantially reduce unwanted electrostatic fields to further improve performance of the device. As a result, the compact electrostatic comb actuator of the present invention occupies only a fraction of the space required for conventional electrostatic comb actuators, while providing a substantial increase in the available drive force (up to one-hundred times).

  16. Hybrid electromechanical actuator and actuation system

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Xu, Tian-Bing (Inventor)

    2008-01-01

    A hybrid electromechanical actuator has two different types of electromechanical elements, one that expands in a transverse direction when electric power is applied thereto and one that contracts in a transverse direction when electric power is applied thereto. The two electromechanical elements are (i) disposed in relation to one another such that the transverse directions thereof are parallel to one another, and (ii) mechanically coupled to one another at least at two opposing edges thereof. Electric power is applied simultaneously to the elements.

  17. Complete corrosion inhibition through graphene defect passivation.

    PubMed

    Hsieh, Ya-Ping; Hofmann, Mario; Chang, Kai-Wen; Jhu, Jian Gang; Li, Yuan-Yao; Chen, Kuang Yao; Yang, Chang Chung; Chang, Wen-Sheng; Chen, Li-Chyong

    2014-01-28

    Graphene is expected to enable superior corrosion protection due to its impermeability and chemical inertness. Previous reports, however, demonstrate limited corrosion inhibition and even corrosion enhancement of graphene on metal surfaces. To enable the reliable and complete passivation, the origin of the low inhibition efficiency of graphene was investigated. Combining electrochemical and morphological characterization techniques, nanometer-sized structural defects in chemical vapor deposition grown graphene were found to be the cause for the limited passivation effect. Extremely fast mass transport on the order of meters per second both across and parallel to graphene layers results in an inhibition efficiency of only ∼50% for Cu covered with up to three graphene layers. Through selective passivation of the defects by atomic layer deposition (ALD) an enhanced corrosion protection of more than 99% was achieved, which compares favorably with commercial corrosion protection methods.

  18. Backed Bending Actuator

    NASA Technical Reports Server (NTRS)

    Costen, Robert C.; Su, Ji

    2004-01-01

    Bending actuators of a proposed type would partly resemble ordinary bending actuators, but would include simple additional components that would render them capable of exerting large forces at small displacements. Like an ordinary bending actuator, an actuator according to the proposal would include a thin rectangular strip that would comprise two bonded layers (possibly made of electroactive polymers with surface electrodes) and would be clamped at one end in the manner of a cantilever beam. Unlike an ordinary bending actuator, the proposed device would include a rigid flat backplate that would support part of the bending strip against backward displacement; because of this feature, the proposed device is called a backed bending actuator. When an ordinary bending actuator is inactive, the strip typically lies flat, the tip displacement is zero, and the force exerted by the tip is zero. During activation, the tip exerts a transverse force and undergoes a bending displacement that results from the expansion or contraction of one or more of the bonded layers. The tip force of an ordinary bending actuator is inversely proportional to its length; hence, a long actuator tends to be weak. The figure depicts an ordinary bending actuator and the corresponding backed bending actuator. The bending, the tip displacement (d(sub t)), and the tip force (F) exerted by the ordinary bending actuator are well approximated by the conventional equations for the loading and deflection of a cantilever beam subject to a bending moment which, in this case, is applied by the differential expansion or contraction of the bonded layers. The bending, displacement, and tip force of the backed bending actuator are calculated similarly, except that it is necessary to account for the fact that the force F(sub b) that resists the displacement of the tip could be sufficient to push part of the strip against the backplate; in such a condition, the cantilever beam would be effectively shortened

  19. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Yang; Meng, Wen-Jin; Swathirajan, Swathy; Harris, Stephen J.; Doll, Gary L.

    1997-01-01

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell's operating environment. Stainless steels rich in CR, Ni, and Mo are particularly effective protective interlayers.

  20. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Y.; Meng, W.J.; Swathirajan, S.; Harris, S.J.; Doll, G.L.

    1997-04-29

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell`s operating environment. Stainless steels rich in Cr, Ni, and Mo are particularly effective protective interlayers. 6 figs.

  1. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Yang; Meng, Wen-Jin; Swathirajan, Swathy; Harris, Stephen Joel; Doll, Gary Lynn

    2001-07-17

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell's operating environment. Stainless steels rich in CR, Ni, and Mo are particularly effective protective interlayers.

  2. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Yang; Meng, Wen-Jin; Swathirajan, Swathy; Harris, Stephen Joel; Doll, Gary Lynn

    2002-01-01

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell's operating environment. Stainless steels rich in CR, Ni, and Mo are particularly effective protective interlayers.

  3. Non-collinear valve actuator

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2012-01-01

    A non-collinear valve actuator includes a primary actuating system and a return spring system with each applying forces to a linkage system in order to regulate the flow of a quarter-turn valve. The primary actuating system and return spring system are positioned non-collinearly, which simply means the primary actuating system and return spring system are not in line with each other. By positioning the primary actuating system and return spring system in this manner, the primary actuating system can undergo a larger stroke while the return spring system experiences significantly less displacement. This allows the length of the return spring to be reduced due to the minimization of displacement thereby reducing the weight of the return spring system. By allowing the primary actuating system to undergo longer strokes, the weight of the primary actuating system may also be reduced. Accordingly, the weight of the non-collinear valve actuator is reduced.

  4. 49 CFR 193.2635 - Monitoring corrosion control.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Monitoring corrosion control. 193.2635 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2635 Monitoring corrosion control. Corrosion protection provided as required by this subpart must be periodically monitored to give...

  5. 49 CFR 193.2635 - Monitoring corrosion control.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Monitoring corrosion control. 193.2635 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2635 Monitoring corrosion control. Corrosion protection provided as required by this subpart must be periodically monitored to give...

  6. 49 CFR 193.2635 - Monitoring corrosion control.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Monitoring corrosion control. 193.2635 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2635 Monitoring corrosion control. Corrosion protection provided as required by this subpart must be periodically monitored to give...

  7. 49 CFR 193.2635 - Monitoring corrosion control.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Monitoring corrosion control. 193.2635 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2635 Monitoring corrosion control. Corrosion protection provided as required by this subpart must be periodically monitored to give...

  8. Electrochemical Fabrication and Characterization of Corrosion-Resistant, Ternary, Lead-Based Alloys as a New Material for Steel Surface Protection

    NASA Astrophysics Data System (ADS)

    Aliyev, A. Sh.; Tahirli, H. M.; Elrouby, Mahmoud; Soltanova, N. Sh.; Tagiev, D. B.

    2016-06-01

    This article presents the study of the synthesis of the ternary Pb-Sb-Te alloy on the stainless steel substrate via electrochemical method. The corrosion resistance of the electrodeposited alloy has been investigated via subjecting the electro-synthesized alloy to a corrosive medium containing sulfide ions; this medium is similar to the petroleum refining environment. The resulting film of the electrodeposited alloy was analyzed by the scanning electron microscope, energy-dispersive X-ray analysis, and X-ray diffraction to determine the morphology and the phase structure of the electrodeposited film. It was found that the electrodeposited Pb-Sb-Te alloy thin film is a multiphase composition. The obtained data reveal that the most corrosion-resistant phase is the PbSb2Te4 alloy.

  9. Fabrication of FDTS-modified PDMS-ZnO nanocomposite hydrophobic coating with anti-fouling capability for corrosion protection of Q235 steel.

    PubMed

    Arukalam, Innocent O; Oguzie, Emeka E; Li, Ying

    2016-12-15

    Perfluorodecyltrichlorosilane-based poly(dimethylsiloxane)-ZnO (FDTS-based PDMS-ZnO) nanocomposite coating with anti-corrosion and anti-fouling capabilities has been prepared using a one-step fabrication technique. XPS analysis and contact angle measurements showed the fluorine content to increase, while the hydrophobicity of the coatings decreased with addition of FDTS. XRD analysis revealed existence of ZnO nanoparticles of dimensions ranging from 11.45 to 93.01nm on the surface of coatings, with the mean particle size decreasing with FDTS addition, and was confirmed by SEM and TEM observations. Interestingly, the anti-corrosion performance and mechanical properties of the coatings increased remarkably on addition of FDTS. Indeed, the observed low adhesion strength, surface energies and the outstanding anti-corrosive properties imply that the obtained coating would be useful in anti-fouling applications.

  10. Biofilms: strategies for metal corrosion inhibition employing microorganisms.

    PubMed

    Zuo, Rongjun

    2007-10-01

    Corrosion causes dramatic economic loss. Currently widely used corrosion control strategies have disadvantages of being expensive, subject to environmental restrictions, and sometimes inefficient. Studies show that microbial corrosion inhibition is actually a common phenomenon. The present review summarizes recent progress in this novel strategy: corrosion control using beneficial bacteria biofilms. The possible mechanisms may involve: (1) removal of corrosive agents (such as oxygen) by bacterial physiological activities (e.g., aerobic respiration), (2) growth inhibition of corrosion-causing bacteria by antimicrobials generated within biofilms [e.g., sulfate-reducing bacteria (SRB) corrosion inhibition by gramicidin S-producing Bacillus brevis biofilm], (3) generation of protective layer by biofilms (e.g., Bacillus licheniformis biofilm produces on aluminum surface a sticky protective layer of gamma-polyglutamate). Successful utilization of this novel strategy relies on advances in study at the interface of corrosion engineering and biofilm biology.

  11. Digital Actuator Technology

    SciTech Connect

    Ken Thomas; Ted Quinn; Jerry Mauck; Richard Bockhorst

    2014-09-01

    There are significant developments underway in new types of actuators for power plant active components. Many of these make use of digital technology to provide a wide array of benefits in performance of the actuators and in reduced burden to maintain them. These new product offerings have gained considerable acceptance in use in process plants. In addition, they have been used in conventional power generation very successfully. This technology has been proven to deliver the benefits promised and substantiate the claims of improved performance. The nuclear industry has been reluctant to incorporate digital actuator technology into nuclear plant designs due to concerns due to a number of concerns. These could be summarized as cost, regulatory uncertainty, and a certain comfort factor with legacy analog technology. The replacement opportunity for these types of components represents a decision point for whether to invest in more modern technology that would provide superior operational and maintenance benefits. Yet, the application of digital technology has been problematic for the nuclear industry, due to qualification and regulatory issues. With some notable exceptions, the result has been a continuing reluctance to undertake the risks and uncertainties of implementing digital actuator technology when replacement opportunities present themselves. Rather, utilities would typically prefer to accept the performance limitations of the legacy analog actuator technologies to avoid impacts to project costs and schedules. The purpose of this report is to demonstrate that the benefits of digital actuator technology can be significant in terms of plant performance and that it is worthwhile to address the barriers currently holding back the widespread development and use of this technology. It addresses two important objectives in pursuit of the beneficial use of digital actuator technology for nuclear power plants: 1. To demonstrate the benefits of digital actuator

  12. Folded dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Carpi, Federico; Salaris, Claudio; DeRossi, Danilo

    2007-04-01

    Polymer-based linear actuators with contractile ability are currently demanded for several types of applications. Within the class of dielectric elastomer actuators, two basic configurations are available today for such a purpose: the multi-layer stack and the helical structure. The first consists of several layers of elementary planar actuators stacked in series mechanically and parallel electrically. The second configuration relies on a couple of helical compliant electrodes alternated with a couple of helical dielectrics. The fabrication of both these configurations presents some specific drawbacks today, arising from the peculiarity of each structure. Accordingly, the availability of simpler solutions may boost the short-term use of contractile actuators in practical applications. For this purpose, a new configuration is here described. It consists of a monolithic structure made of an electroded sheet, which is folded up and compacted. The resulting device is functionally equivalent to a multi-layer stack with interdigitated electrodes. However, with respect to a stack the new configuration is advantageously not discontinuous and can be manufactured in one single phase, avoiding layer-by-layer multi-step procedures. The development and preliminary testing of prototype samples of this new actuator made of a silicone elastomer are presented here.

  13. The 43rd annual corrosion survey

    SciTech Connect

    Not Available

    1992-03-01

    Applying the science of corrosion prevention to energy (petroleums, oil, LNG) pipelines in actual field operating conditions is a vital aspect of safely and efficiently operating a pipeline system. Ignoring corrosion prevention will allow this never-sleeping enemy to steal the strength from steel pipelines, turning them into dangerous junk. Various methods, techniques and technologies are available to the corrosion control department of cross-country pipelines and gas distribution utilities around the world. Every year, billions of dollars on corrosion control, including everything from coatings to cathodic protection facilities to pigging, are spent to keep these energy pipeline systems in peak operational efficiency. This paper reports that for more than 4 decades, this corrosion survey has sought out the opinions of corrosion control experts, asking them what are the problems they face daily and innovative solutions they have tried to help solve these problems.

  14. 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.

  15. Hydraulically actuated artificial muscles

    NASA Astrophysics Data System (ADS)

    Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

    2012-04-01

    Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

  16. Corrosion control of steel-reinforced concrete

    NASA Astrophysics Data System (ADS)

    Chung, D. D. L.

    2000-10-01

    The methods and materials for corrosion control of steel-reinforced concrete are reviewed. The methods are steel surface treatment, the use of admixtures in concrete, surface coating on concrete, and cathodic protection.

  17. Fault tolerant linear actuator

    DOEpatents

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  18. Hydraulic involute cam actuator

    DOEpatents

    Love, Lonnie J [Knoxville, TN; Lind, Randall F [Loudon, TX

    2011-11-01

    Mechanical joints are provided in which the angle between a first coupled member and a second coupled member may be varied by mechanical actuators. In some embodiments the angle may be varied around a pivot axis in one plane and in some embodiments the angle may be varied around two pivot axes in two orthogonal planes. The joints typically utilize a cam assembly having two lobes with an involute surface. Actuators are configured to push against the lobes to vary the rotation angle between the first and second coupled member.

  19. Tetherless thermobiochemically actuated microgrippers

    PubMed Central

    Leong, Timothy G.; Randall, Christina L.; Benson, Bryan R.; Bassik, Noy; Stern, George M.; Gracias, David H.

    2009-01-01

    We demonstrate mass-producible, tetherless microgrippers that can be remotely triggered by temperature and chemicals under biologically relevant conditions. The microgrippers use a self-contained actuation response, obviating the need for external tethers in operation. The grippers can be actuated en masse, even while spatially separated. We used the microgrippers to perform diverse functions, such as picking up a bead on a substrate and the removal of cells from tissue embedded at the end of a capillary (an in vitro biopsy). PMID:19139411

  20. A Multifunctional Smart Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  1. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  2. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  3. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  4. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  5. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  6. NASA's Corrosion Technology Laboratory at the Kennedy Space Center: Anticipating, Managing, and Preventing Corrosion

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina

    2014-01-01

    Corrosion is the degradation of a material that results from its interaction with the environment. The marine environment at NASAs Kennedy Space Center (KSC) has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the United States. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pads were rendered even more severe by the 70 tons of highly corrosive hydrochloric acid that were generated by the solid rocket boosters. Numerous failures at the launch pads are caused by corrosion.The structural integrity of ground infrastructure and flight hardware is critical to the success, safety, cost, and sustainability of space missions. As a result of fifty years of experience with launch and ground operations in a natural marine environment that is highly corrosive, NASAs Corrosion Technology Laboratory at KSC is a major source of corrosion control expertise in the launch and other environments. Throughout its history, the Laboratory has evolved from what started as an atmospheric exposure facility near NASAs launch pads into a world-wide recognized capability that provides technical innovations and engineering services in all areas of corrosion for NASA and external customers.This presentation will provide a historical overview of the role of NASAs Corrosion Technology in anticipating, managing, and preventing corrosion. One important challenge in managing and preventing corrosion involves the detrimental impact on humans and the environment of what have been very effective corrosion control strategies. This challenge has motivated the development of new corrosion control technologies that are more effective and environmentally friendly. Strategies for improved corrosion protection and durability can have a huge impact on the economic sustainability of human spaceflight operations.

  7. Performance and Analysis of Perfluoropolyalkyl Ether Grease Used on Space Shuttle Actuators--A Case Study

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Street, Kenneth W., Jr.; Zaretsky, Erwin V.

    2013-01-01

    Actuators used on the United States space shuttle fleet are lubricated with unspecified amounts of Braycote 601 (Castrol Braycote) grease consisting of a perfluoropolyalkyl ether (PFPAE) base oil thickened with a polytetrafluoroethylene (PTFE) filler. Each shuttle has four body flap actuators (BFAs) (two on each wing) on a common segmented shaft and four rudder speed brake (RSB) actuators. The actuators were designed to operate for 10 years and 100 flights without periodic relubrication. Visible inspection of two partially disassembled RSB actuators in continuous use for 19 years raised concerns over possible grease degradation due to discoloration of the grease on several places on the surfaces of the gears. Inspection revealed fretting, micropitting, wear and corrosion of the bearings and gears. A small amount of oil dripped from the disassembled actuators. Whereas new grease is beige in appearance, the discolored grease consisted of both grey and reddish colors. Grease samples taken from the actuators together with representative off-the-shelf new and unused grease samples were analyzed by gravimetry for oil content; by inductively coupled plasma spectroscopy (ICP) for metals content; Fourier transform infrared (FTIR) spectroscopy for base oil decomposition; and by size exclusion chromatography (SEC) for determination of the molecular weight distributions of the grease oil. The Braycote 601 grease was stable after 19 years of continuous use in the sealed RSB actuators and was fit for its intended purpose. There were no significant chemical differences between the used grease samples and new and unused samples. Base oil separation was not significant within the sealed actuators. No corrosive effect in the form of iron fluoride was detected. The grey color of grease samples was due to metallic iron. The red color was due to oxidation of the metallic wear particles from the gears and the bearings comprising the actuators.

  8. Corrosion of ductile iron piping

    SciTech Connect

    Szeliga, M.

    1995-12-31

    A compilation of 20 classic NACE papers on the subject, dating from 1957 to 1994. Papers include: Corrosion of Municipal Iron Watermains, Protecting Water Pipelines with Pipeline Coatings Conforming to American Water Works Association Coating Standards, Analysis of Aged Water Distribution Systems, and many more.

  9. Fabrication of Polyurethane Dielectric Actuators

    DTIC Science & Technology

    2005-01-01

    a summary of a 3 year Technology Investment Fund Project entitled “Dielectric Polymer Actuators for Active/ Passive Vibration Isolation”, which was...completed in March 2005. The purpose of this project was to investigate dielectric polymer materials for potential use in active/ passive vibration...devices and systems based on dielectric polymer actuators. Keywords: dielectric actuators, electroactive polymers , Technology Investment Fund 1

  10. Graphene: corrosion-inhibiting coating.

    PubMed

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

  11. Aircraft Corrosion

    DTIC Science & Technology

    1981-08-01

    chlore mais dans une proportion semblable b cells d’une eau de vil)e ; - lea solides, d’aprbs lea analyses chimique et criatallographique, paraissaiont...IATA member airlines at $100 million based on 1976 operations. Thus the numbers are large, but detailed analyses on specific aircraft types, in known...demonstrate this in any quantitative way with accurate figures. Better information is required on the cost of corrosion, together with analyses of the

  12. "Mighty Worm" Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Bamford, Robert M.; Wada, Ben K.; Moore, Donald M.

    1994-01-01

    "Mighty Worm" piezoelectric actuator used as adjustable-length structural member, active vibrator or vibration suppressor, and acts as simple (fixed-length) structural member when inactive. Load force not applied to piezoelectric element in simple-structural-member mode. Piezoelectric element removed from load path when not in use.

  13. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2002-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  14. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2000-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  15. Electromechanical flight control actuator

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The feasibility of using an electromechanical actuator (EMA) as the primary flight control equipment in aerospace flight is examined. The EMA motor design is presented utilizing improved permanent magnet materials. The necessary equipment to complete a single channel EMA using the single channel power electronics breadboard is reported. The design and development of an improved rotor position sensor/tachometer is investigated.

  16. Bistable microelectromechanical actuator

    DOEpatents

    Fleming, James G.

    1999-01-01

    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing.

  17. Bistable microelectromechanical actuator

    DOEpatents

    Fleming, J.G.

    1999-02-02

    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing. 49 figs.

  18. Piezoelectric actuator renaissance

    NASA Astrophysics Data System (ADS)

    Uchino, Kenji

    2015-03-01

    This paper resumes the content of the invited talk of the author, read at the occasion of the International Workshop on Relaxor Ferroelectrics, IWRF 14, held on October 12-16, 2014 in Stirin, Czech Republic. It reviews the recent advances in materials, designing concepts, and new applications of piezoelectric actuators, as well as the future perspectives of this area.

  19. Demonstration of Corrosion-Resistant Coatings for Air-Conditioning Coils and Fins

    DTIC Science & Technology

    2015-06-01

    cost effectiveness of two of the newer coatings to protect build- ing air-conditioning condenser evaporator coils and fins from corrosion . Exposure...on-site coupons under this test be periodically revisited over the next 30 years, and the corrosion - protection performance of the two coating ...quality coating (such as the demonstrated technologies) would protect aluminum from corrosion , even in more corrosive atmospheres. Clearly, each of the

  20. Shadow corrosion

    NASA Astrophysics Data System (ADS)

    Ramasubramanian, N.

    2004-07-01

    An electrochemical mechanism, based on energetically favored complimentary reduction and oxidation reactions, operating in conjunction with radiolysis is proposed for explaining the shadow corrosion phenomenon observed under BWR conditions. The electrochemical reaction on platinum and nickel alloys (Inconel and X-750) is the oxidation of H 2O 2 to produce a localized enhancement in the concentrations of HO 2 and O 2. Energy level of the conduction band of ZrO 2 matches well with that for the reduction of HO 2 and O 2 regenerating H 2O 2. This reduction of the powerful oxidants, stimulates electron emission in ZrO 2 which then is balanced by increased oxidation of zirconium to generate additional electrons and hence also anion vacancies. A coupling between Zircaloy and platinum or nickel alloy is provided by H + transport, the source for initiating shadow corrosion, to Zircaloy-2 (Zircaloy-2 negative relative to platinum or the nickel alloy) in the gap between the materials. An enhanced localized corrosion of Zircaloy-2 occurs, its incidence dependent upon the transport of HO 2, O 2, H + and H 2O 2 in the coolant in the gap.

  1. Thermally Actuated Hydraulic Pumps

    NASA Technical Reports Server (NTRS)

    Jones, Jack; Ross, Ronald; Chao, Yi

    2008-01-01

    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  2. Corrosion protection of aluminum bipolar plates with polyaniline coating containing carbon nanotubes in acidic medium inside the polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Deyab, M. A.

    2014-12-01

    The effect of addition of carbon nanotubes (CNTs) on the corrosion resistance of conductive polymer coating (polyaniline) that coated aluminum bipolar plates in acidic environment inside the PEM fuel cell (0.1 M H2SO4) was investigated using electrical conductivity, polarization and electrochemical impedance spectroscopy (EIS) measurements. Scanning electron microscopy (SEM) was used to characterize the coating morphology. The results show that the addition of CNTs to polyaniline coating enhanced the electrical conductivity and the corrosion resistance of polyaniline polymer. The inhibition efficiency of polyaniline polymer increased with increasing CNTs concentration. The best inhibition was generally obtained at 0.8% CNTs concentration in the acidic medium. This was further confirmed by decreasing the oxygen and water permeability and increasing coating adhesion in the presence of CNTs. EIS measurements indicated that the incorporation of CNTs in coating increased both the charge transfer and pore resistances while reducing the double layer capacitance.

  3. Alternative methods for evaluating corrosion deterioration on existing USTs prior to upgrading with cathodic protection as defined in ASTM standard practice ES40-94

    SciTech Connect

    Bushman, J.B.

    1995-12-31

    In November, 1994 ASTM approved the issuance of Emergency Standard ES40-94 defining new means for evaluating the corrosion condition of existing USTs. This paper presents the background information which lead to the formation of a committee which undertook the development of the new standard, general descriptions of each of the methodologies provided, information on the standard approval process and an outline of the continuing work effort to reissue the standard with minor editorial modifications as a regular ASTM standard.

  4. Chemical Industry Corrosion Management

    SciTech Connect

    2003-02-01

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

  5. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical report, January 14, 1997--August 14, 1997

    SciTech Connect

    Schorr, B.S.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1997-08-31

    Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. Bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. Also, to deposit model Ni-Al{sub 2}O{sub 3} coatings, an electrodeposition technique was developed and coatings with various volume fractions (0-35%) of Al{sub 2}O{sub 3} were produced. The powder and electrodeposition processing of Ni-Al{sub 2}O{sub 3} Composites provide the ability to produce two phase microstructure without changing the microstructure of the matrix material. Therefore, the effect of hard second phase particles size and volume fraction on erosion resistance could be analyzed.

  6. Dielectric Actuation of Polymers

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  7. pH Responsive Microcapsules for Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Li, Wenyan; Muehlberg, Aaron; Boraas, Samuel; Webster, Dean; JohnstonGelling, Victoria; Croll, Stuart; Taylor, S Ray; Contu, Francesco

    2008-01-01

    The best coatings for corrosion protection provide not only barriers to the environment, but also a controlled release of a corrosion inhibitor, as demanded by the presence of corrosion or mechanical damage. NASA has developed pH sensitive microcapsules (patent pending) that can release their core contents when corrosion starts. The objectives of the research presented here were to encapsulate non-toxic corrosion inhibitors, to incorporate the encapsulated inhibitors into paint formulations, and to test the ability of the paints to control corrosion. Results showed that the encapsulated corrosion inhibitors, specifically Ce(NO3)3 , are effective to control corrosion over long periods of time when incorporated at relatively high pigment volume concentrations into a paint formulation.

  8. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Inhibitors which appeared promising in previous tests and additional inhibitors including several proprietary products were evaluated. Evaluation of the inhibitors was based on corrosion protection afforded an aluminum-mild steel-copper-stainless steel assembly in a hot corrosive water. Of the inhibitors tested two were found to be effective and show promise for protecting multimetallic solar heating systems.

  9. Method for inhibiting corrosion of nickel-containing alloys

    DOEpatents

    DeVan, J.H.; Selle, J.E.

    Nickel-containing alloys are protected against corrosion by contacting the alloy with a molten alkali metal having dissolved therein aluminum, silicon or manganese to cause the formation of a corrosion-resistant intermetallic layer. Components can be protected by applying the coating after an apparatus is assembled.

  10. 40 CFR 261.22 - Characteristic of corrosivity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Section 261.22 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Characteristic of corrosivity. (a) A solid waste exhibits the characteristic of corrosivity if a representative... Methods for Evaluating Solid Waste, Physical/Chemical Methods,” EPA Publication SW-846, as incorporated...

  11. Corrosion Damage Functions

    SciTech Connect

    Jones, Russell H.

    2002-11-30

    Corrosion damage can lead to reduced operational lifetimes. Often this damage is not as obvious as general corrosion but takes the form of pits, intergranular corrosion, crevice corrosion and hydrogen absorption. These types of corrosion damage lead to stress corrosion cracking, hydrogen induced cracking and corrosion fatigue. A critical step in defining a corrosion damage function is determining the relationship between the corrosion damage, the resulting crack propagation mechanism and component lifetimes. The sequence of events is often some localized corrosion event such as pitting, transition of the pit to a planar crack, propagation of this short crack, transition of the short crack to long crack conditions and continued propagation through Stage I, II, and III of the long crack SCC regimes. A description of critical corrosion damage processes and examples of the transition to long crack SCC conditions will be discussed.

  12. A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS

    SciTech Connect

    BOOMER, K.D.

    2007-08-21

    The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

  13. Evaluation and control of environmental corrosion for aluminum and steel alloys

    NASA Technical Reports Server (NTRS)

    Franklin, D. B.

    1977-01-01

    Corrosion protection systems for aerospace application and the effects of surface treatments and methods of controlling stress corrosion are evaluated. Chromate pigmented systems were found to be most effective for aluminum alloys; zinc-rich coatings gave the greatest protection to steel alloys. Various steel and aluminum alloys are rated for stress corrosion resistance.

  14. General Corrosion and Localized Corrosion of the Drip Shield

    SciTech Connect

    F. Hua

    2004-09-16

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

  15. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, M.A.; Ciarlo, D.R.; Lee, A.P.; Krulevitch, P.A.

    1997-07-08

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The ``micro`` size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed. 22 figs.

  16. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, Milton A.; Ciarlo, Dino R.; Lee, Abraham P.; Krulevitch, Peter A.

    1997-01-01

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The "micro" size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed.

  17. Electrical Actuation Technology Bridging

    NASA Technical Reports Server (NTRS)

    Hammond, Monica (Compiler); Sharkey, John (Compiler)

    1993-01-01

    This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document.

  18. Microfabricated therapeutic actuators

    DOEpatents

    Lee, Abraham P.; Northrup, M. Allen; Ciarlo, Dino R.; Krulevitch, Peter A.; Benett, William J.

    1999-01-01

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use.

  19. Microfabricated therapeutic actuators

    DOEpatents

    Lee, A.P.; Northrup, M.A.; Ciarlo, D.R.; Krulevitch, P.A.; Benett, W.J.

    1999-06-15

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use. 8 figs.

  20. Scissor thrust valve actuator

    DOEpatents

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

    2006-08-29

    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  1. Dissolution actuated sample container

    SciTech Connect

    Nance, Thomas A.; McCoy, Frank T.

    2013-03-26

    A sample collection vial and process of using a vial is provided. The sample collection vial has an opening secured by a dissolvable plug. When dissolved, liquids may enter into the interior of the collection vial passing along one or more edges of a dissolvable blocking member. As the blocking member is dissolved, a spring actuated closure is directed towards the opening of the vial which, when engaged, secures the vial contents against loss or contamination.

  2. Shape memory alloy actuator

    DOEpatents

    Varma, Venugopal K.

    2001-01-01

    An actuator for cycling between first and second positions includes a first shaped memory alloy (SMA) leg, a second SMA leg. At least one heating/cooling device is thermally connected to at least one of the legs, each heating/cooling device capable of simultaneously heating one leg while cooling the other leg. The heating/cooling devices can include thermoelectric and/or thermoionic elements.

  3. Thermally actuated thermionic switch

    DOEpatents

    Barrus, Donald M.; Shires, Charles D.

    1988-01-01

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  4. Thermally actuated thermionic switch

    DOEpatents

    Barrus, D.M.; Shires, C.D.

    1982-09-30

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  5. Passively actuated valve

    SciTech Connect

    Modro, S. Michael; Ougouag, Abderrafi M.

    2005-09-20

    A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

  6. Linear mass actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)

    1992-01-01

    A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.

  7. Cylindrical Piezoelectric Fiber Composite Actuators

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

  8. Microelectromechanical (MEM) thermal actuator

    DOEpatents

    Garcia, Ernest J [Albuquerque, NM; Fulcher, Clay W. G. [Sandia Park, NM

    2012-07-31

    Microelectromechanical (MEM) buckling beam thermal actuators are disclosed wherein the buckling direction of a beam is constrained to a desired direction of actuation, which can be in-plane or out-of-plane with respect to a support substrate. The actuators comprise as-fabricated, linear beams of uniform cross section supported above the substrate by supports which rigidly attach a beam to the substrate. The beams can be heated by methods including the passage of an electrical current through them. The buckling direction of an initially straight beam upon heating and expansion is controlled by incorporating one or more directional constraints attached to the substrate and proximal to the mid-point of the beam. In the event that the beam initially buckles in an undesired direction, deformation of the beam induced by contact with a directional constraint generates an opposing force to re-direct the buckling beam into the desired direction. The displacement and force generated by the movement of the buckling beam can be harnessed to perform useful work, such as closing contacts in an electrical switch.

  9. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    PubMed Central

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion. PMID:24558346

  10. Monitoring corrosion of steel bars in reinforced concrete structures.

    PubMed

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion.

  11. Analysis of corrosion layers on protective coatings and high temperature materials in simulated service environments of modern power plants using SNMS, SIMS, SEM, TEM, RBS and X-ray diffraction studies.

    PubMed

    Nickel, H; Quadakkers, W J; Singheiser, L

    2002-10-01

    In three different examples, the effects of the oxidation behaviour as well as the microstructural stability of high temperature materials and protective coatings was determined by combining the results of kinetic studies with extensive analytical investigations using, among other techniques, SNMS, SIMS, SEM, TEM, Rutherford back scattering (RBS) as well as X-ray diffraction. 1). The effect of water vapour on the oxidation behaviour of 9% Cr steels in simulated combustion gases has been determined. The effects of O2 and H2O content on the oxidation behaviour of 9% Cr steel in the temperature range 600-800 degrees C showed that in dry oxygen a protective scale was formed with an oxidation rate controlled by diffusion in the protective scale. In the presence of water vapour, after an incubation period, the scales became non-protective as a result of a change in the oxidation limiting process. The destruction of the protective scale by water vapour does not only depend on H2O content but also on the H2O/O2-ratio. 2). The increase of component surface temperature in modern gas turbines leads to an enhanced oxidation attack of the blade coating. Improvements in corrosion resistance and longer lifetime thermal barrier coatings in gas turbines have been achieved by improvement of the high temperature properties of MCrAlY coatings by additions of minor alloying elements such as yttrium, silicon and titanium. 3). The use of oxide dispersion strengthened (ODS) alloys provides excellent creep resistance up to much higher temperatures than can be achieved with conventional wrought or cast alloys in combination with suitable high temperature oxidation/corrosion resistance. Investigation of the growth mechanisms of protective chromia and alumina scales were examined by a two-stage oxidation method with 18O tracer. The distribution of the oxygen isotopes in the oxide scale was determined by SIMS and SNMS. The results show the positive influence of a Y2O3 dispersion on the

  12. Distribution of the current on metallic structures with corrosion damage under nonlinear cathodic polarization

    SciTech Connect

    Galimov, A.A.; Glazov, N.P.; Ivanov, V.T.

    1985-08-01

    The protection of metallic structures from corrosion is effected by cathodic polarization and protective coatings. At sites of damage extending through the insulation an intense corrosion process, which causes the formation of corrosion pits, in which signifiant redistribution of the protective current occurs, takes place. Considered in this paper is the distribution of the current on an electrode with a corrosion pit of arbitrary shape in the example of an electrochemical system consisting of disk electrodes located in a cylindrical bath with a lateral insulator surface. The overall analysis of the numerical results points out the significant redistribution of the current on a protected metallic surface when corrosion pits appear.

  13. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2010-01-01

    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  14. Direct drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1998-03-10

    A positive-drive field actuator motor is described which includes a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 62 figs.

  15. Fault-tolerant rotary actuator

    DOEpatents

    Tesar, Delbert

    2006-10-17

    A fault-tolerant actuator module, in a single containment shell, containing two actuator subsystems that are either asymmetrically or symmetrically laid out is provided. Fault tolerance in the actuators of the present invention is achieved by the employment of dual sets of equal resources. Dual resources are integrated into single modules, with each having the external appearance and functionality of a single set of resources.

  16. Linear Proof-Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III; Crossley, Edward A.; Miller, James B.; Jones, Irby W.; Davis, C. Calvin; Behun, Vaughn D.; Goodrich, Lewis R., Sr.

    1995-01-01

    Linear proof-mass actuator (LPMA) is friction-driven linear mass actuator capable of applying controlled force to structure in outer space to damp out oscillations. Capable of high accelerations and provides smooth, bidirectional travel of mass. Design eliminates gears and belts. LPMA strong enough to be used terrestrially where linear actuators needed to excite or damp out oscillations. High flexibility designed into LPMA by varying size of motors, mass, and length of stroke, and by modifying control software.

  17. Direct drive field actuator motors

    SciTech Connect

    Grahn, Allen R.

    1998-01-01

    A positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  18. Application of ultrasound irradiation on sol-gel technique for corrosion protection of Al65Cu20Fe15 alloy powder

    NASA Astrophysics Data System (ADS)

    Liang, Bo; Zhang, Baoyan; Wang, Guodong; Li, Di; Zhang, Xiaoming

    2013-11-01

    Al65Cu20Fe15 alloy powder was firstly encapsulated by the conventional sol-gel technique utilizing tetraethoxysilane (TEOS) as the precursor in order to improve its corrosion resistance. The optimization was based on nine well-planned orthogonal experiments (L9 (34)). Four main factors in the encapsulation process (i.e. reaction temperature, ethylenediamine concentration, TEOS concentration and feeding method) were investigated. According to the visual analyses of the result, the optimum condition was obtained. Based on the optimal condition in the conventional sol-gel technique, the encapsulation process was then conducted under ultrasonic irradiation. The effects of ultrasound amplitude and irradiation time on the encapsulation process were also studied. FTIR, XRD, SEM, DLS and EDS were also used to characterize the resulting sample. Finally, the corrosion inhibition efficiency of encapsulated powder attained 99.3% in the acidic condition of pH 1, and the average grain size (d50) of the encapsulated powder was just 4.8% larger than that of the raw powder, implying that there was a thin silica film on the surface of powder.

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

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  20. Launch Pad Coatings for Smart Corrosion Control

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  1. Electrolysis-based diaphragm actuators

    NASA Astrophysics Data System (ADS)

    Pang, C.; Tai, Y.-C.; Burdick, J. W.; Andersen, R. A.

    2006-02-01

    This work presents a new electrolysis-based microelectromechanical systems (MEMS) diaphragm actuator. Electrolysis is a technique for converting electrical energy to pneumatic energy. Theoretically electrolysis can achieve a strain of 136 000% and is capable of generating a pressure above 200 MPa. Electrolysis actuators require modest electrical power and produce minimal heat. Due to the large volume expansion obtained via electrolysis, small actuators can create a large force. Up to 100 µm of movement was achieved by a 3 mm diaphragm. The actuator operates at room temperature and has a latching and reversing capability.

  2. 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.

  3. Metallized coatings for pressure vessel corrosion

    SciTech Connect

    Hankirk, M. ); Hansen, D.S. )

    1994-09-01

    Metallized coatings have been successful for many years in providing sacrificial protection to pressure vessels in high-temperature applications in which they are susceptible to localized corrosion, hydrogen blistering, erosion, and pitting. In addition, when corrosion allowances have decreased or have been eliminated after many years of service, metallized coatings can be used to restore the allowances and extend the life of the equipment.

  4. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  5. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  6. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  7. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  8. 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.

  9. Lead screw linear actuator

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1980-01-01

    A linear actuator which can apply high forces is described, which includes a reciprocating rod having a threaded portion engaged by a nut that is directly coupled to the rotor of an electric motor. The nut is connected to the rotor in a manner that minimizes loading on the rotor, by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded rod portion, with an oilcarrying groove in the nut being interrupted.

  10. Piezoelectric actuated gimbal

    DOEpatents

    Tschaggeny, Charles W.; Jones, Warren F.; Bamberg, Eberhard

    2011-09-13

    A gimbal is described and which includes a fixed base member defining an axis of rotation; a second member concentrically oriented relative to the axis of rotation; a linear actuator oriented in immediate, adjoining force transmitting relation relative to the base member or to the second member, and which applies force along a linear axis which is tangential to the axis of rotation so as to cause the second member to rotate coaxially relative to the fixed base member; and an object of interest mounted to the second member such that the object of interest is selectively moved relative to the base member about the axis of rotation.

  11. Experimental and theoretical analysis of polymerization reaction process on the polydopamine membranes and its corrosion protection properties for 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Yu, Fei; Chen, Shougang; Chen, Yan; Li, Houmin; Yang, Lejiao; Chen, Yuanyuan; Yin, Yansheng

    2010-10-01

    Inspired by the bio-adhesion principle, polydopamine membrane was fabricated by dipping the 304 Stainless Steel (304 SS) substrate into an aqueous alkaline dopamine solution and its possible reaction mechanism and the temperature effect were studied. The membranes were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), surface reflection Fourier transform infrared spectrum (SR-FTIR), UV-visible spectrum. The polymerization reactions of dopamine in solution were also analyzed by the LUMO energies, simulated infrared spectrum and HOMO-LUMO energy gaps of selected structure models calculation, and the possible interfacial reaction mechanism was also discussed by the molecular orbital analysis of melanin clusters. Moreover, the corrosion behaviors of the polydopamine films prepared at different temperatures and dipping days were evaluated by the electrochemical impedance spectroscopy (EIS), as well as that of bare 304 SS, especially long stability in 3.5% NaCl solution.

  12. 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.

  13. Corrosion-Control (CC) Program SIMA (Shore Intermediate Maintenance Activity) Pilot CC (Corrosion-Control) Shop Service Test and Technical Support. Volume 2. Appendices A3, A4, A6, A8.

    DTIC Science & Technology

    1985-11-30

    protects against corrosion. The aluminum forms a galvanic coating which becomes the base for the sealing system, without which it cannot be used successfully...Formula 150 and a topcoat system. The resultant coating system protects against corrosion. The aluminum forms a galvanic coating which becomes the base...excess moisture from the surface to be protected prior to applying the corrosion-preventive compound. p Apply a thin uniform coat of corrosion-preventive

  14. The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

    SciTech Connect

    Ruscak, M.; Chvatal, P.; Karnik, D.

    1997-04-01

    One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here.

  15. Actuator operated microvalves

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor)

    2008-01-01

    An actuator operated microvalve and the method of making same is disclosed and claimed. The microvalve comprises a SiC housing which includes a first lower portion and a second upper portion. The lower portion of the SiC housing includes a passageway therethrough, a microvalve seat, and a moveable SiC diaphragm. The SiC diaphragm includes a centrally located boss and radially extending corrugations which may be sinusoidally shaped. The boss of the SiC diaphragm moves and modulates in a range of positions between a closed position wherein the boss interengages said microvalve seat prohibiting communication of fluid through the passageway and a fully open position when the boss is spaced apart from the seat at its maximum permitting communication of fluid through said passageway. The actuator includes a SiC top plate affixed to the boss of the diaphragm and a first electrode and the second upper portion of the SiC housing further includes a second electrode.

  16. Motor actuated vacuum door

    NASA Astrophysics Data System (ADS)

    Hanagud, A. V.

    1986-10-01

    Doors that allow scientific instruments to record and retrieve the observed data are often required to be designed and installed as a part of sounding rocket hardware. The motor-actuated vacuum door was designed to maintain a medium vacuum of the order of 0.0001 torr or better while closed, and to provide an opening 15 inches long x 8.5 inches wide while open for cameras to image Halley's comet. When the electric motor receives the instruction to open the door through the payload battery, timer, and relay circuit, the first operation is to unlock the door. After unlatching, the torque transmitted by the motor to the main shaft through the links opens the door. A microswitch actuator, which rides on the linear motion conversion mechanism, is adjusted to trip the limit switch at the end of the travel. The process is repeated in the reverse order to close the door. 'O' rings are designed to maintain the seal. Door mechanisms similar to the one described have flown on Aerobee 17.018 and Black Brant 27.047 payloads.

  17. Bi-stable optical actuator

    DOEpatents

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  18. Remotely-actuated biomedical switch

    NASA Technical Reports Server (NTRS)

    Lee, R. D.

    1969-01-01

    Remotely-actuated biomedical switching circuit using transistors consumes no power in the off position and can be actuated by a single-frequency telemetry pulse to control implanted instrumentation. Silicon controlled rectifiers permit the circuit design which imposes zero drain on supply batteries when not in use.

  19. Prevention and Control in Corrosion

    DTIC Science & Technology

    2001-03-01

    ferric acid mix’ 1 showed at the moment the best performance. 3. CORROSION PROTECTION Many factors have to be taken into account in order to carry out...nickel metavanadate 7 , Phosphoric Sulfuric Acid anodizingŜ, etc.) have already given promising results. A non-toxic trivalent chromium conversion...coating formed applying dilute solutions of basic chromic sulfate plus hexafluorozirconate has been already successfully proposed’ 9; it appears at the

  20. Actuated Hybrid Mirror Telescope

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory; Redding, David; Lowman, Andrew; Cohen, David; Ohara, Catherine

    2005-01-01

    The figure depicts the planned Actuated Hybrid Mirror Telescope (AHMT), which is intended to demonstrate a new approach to the design and construction of wide-aperture spaceborne telescopes for astronomy and Earth science. This technology is also appropriate for Earth-based telescopes. The new approach can be broadly summarized as using advanced lightweight mirrors that can be manufactured rapidly at relatively low cost. More specifically, it is planned to use precise replicated metallic nanolaminate mirrors to obtain the required high-quality optical finishes. Lightweight, dimensionally stable silicon carbide (SiC) structures will support the nanolaminate mirrors in the required surface figures. To enable diffraction- limited telescope performance, errors in surface figures will be corrected by use of mirror-shape-control actuators that will be energized, as needed, by a wave-front-sensing and control system. The concepts of nanolaminate materials and mirrors made from nanolaminate materials were discussed in several previous NASA Tech Briefs articles. Nanolaminates constitute a relatively new class of materials that can approach theoretical limits of stiffness and strength. Nanolaminate mirrors are synthesized by magnetron sputter deposition of metallic alloys and/or compounds on optically precise master surfaces to obtain optical-quality reflector surfaces backed by thin shell structures. As an integral part of the deposition process, a layer of gold that will constitute the reflective surface layer is deposited first, eliminating the need for a subsequent and separate reflective-coating process. The crystallographic textures of the nanolaminate will be controlled to optimize the performance of the mirror. The entire deposition process for making a nanolaminate mirror takes less than 100 hours, regardless of the mirror diameter. Each nanolaminate mirror will be bonded to its lightweight SiC supporting structure. The lightweight nanolaminate mirrors and Si

  1. Internal Corrosion and Deposition Control

    EPA Science Inventory

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

  2. Galvanic corrosion of beryllium welds

    SciTech Connect

    Hill, M.A.; Butt, D.P.; Lillard, R.S.

    1997-12-01

    Beryllium is difficult to weld because it is highly susceptible to cracking. The most commonly used filler metal in beryllium welds is Al-12 wt.% Si. Beryllium has been successfully welded using Al-Si filler metal with more than 30 wt.% Al. This filler creates an aluminum-rich fusion zone with a low melting point that tends to backfill cracks. Drawbacks to adding a filler metal include a reduction in service temperature, a lowering of the tensile strength of the weld, and the possibility for galvanic corrosion to occur at the weld. To evaluate the degree of interaction between Be and Al-Si in an actual weld, sections from a mock beryllium weldment were exposed to 0.1 M Cl{sup {minus}} solution. Results indicate that the galvanic couple between Be and the Al-Si weld material results in the cathodic protection of the weld and of the anodic dissolution of the bulk Be material. While the cathodic protection of Al is generally inefficient, the high anodic dissolution rate of the bulk Be during pitting corrosion combined with the insulating properties of the Be oxide afford some protection of the Al-Si weld material. Although dissolution of the Be precipitate in the weld material does occur, no corrosion of the Al-Si matrix was observed.

  3. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Deramus, G. E., Jr.

    1977-01-01

    Problems dealing with corrosion and corrosion protection of solar heating and cooling systems are discussed. A test program was conducted to find suitable and effective corrosion inhibitors for systems employing either water or antifreeze solutions for heat transfer and storage. Aluminum-mild-steel-copper-stainless steel assemblies in electrical contact were used to simulate a multimetallic system which is the type most likely to be employed. Several inhibitors show promise for this application.

  4. Smart Coating for Corrosion Indication and Prevention: Recent Progress

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Hintze, Paul; Calle, Luz M.; Buhrow, Jerry; Curran, Jerry; Muehlberg, A. J.; Gelling, V. J.; Webster, D. C.; Croll, S. G.; Contu, F.; Taylor, S. R.

    2009-01-01

    The authors are developing a smart coating system based on pH-triggered release microcapsules. These microcapsules can be incorporated into various coating systems for corrosion detection, protection and self-repair of mechanical coating damage. This paper will present the results from progress made to date in the controlled release properties of these microcapsules as well as in their corrosion indication and corrosion inhibition function.

  5. Corrosion Activities at the NASA Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Heidersbach, Robert H.

    2002-01-01

    This report documents summer faculty fellow efforts in the corrosion test bed at the NASA Kennedy Space Center. During the summer of 2002 efforts were concentrated on three activities: a short course on corrosion control for KSC personnel, evaluation of commercial wash additives used for corrosion control on Army aircraft, and improvements in the testing of a new cathodic protection system under development at KSC.

  6. Dictionary of corrosion and corrosion control: English-German/German-English

    SciTech Connect

    Gross, H.

    1985-01-01

    This dictionary has been complied by coworkers of the Department of Applied Linguistics of the Dresden University of Technology. It comprises the special terms of a highly important economical branch of science and technology. Corrosion-induced damage occurs in every branch of technology, and subsequent losses in money and material are enormous. Experts estimate that about one-third of the annual world production of steel and iron is destroyed by corrosion. Corrosion protection is thus becoming increasingly important in order to solve the problems involved, a profound understanding of corrosion processes and of the possibilities of corrosion control is indispensible. The dictionary comprises approximately 3,000 entries in each part taken from a wide variety of fields.

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

    DTIC Science & Technology

    2009-01-01

    19 Figure 8. Surfaces of unpainted 15 - 5PH and S53 after 12 month beach exposureC Kure Beach...strength steel used in landing gear, and equivalent in corrosion resistance to the lower strength 15 - 5PH stainless steel used in actuators. It also...for using S53 in place of lower strength corrosion-resistant (CRES) steels such as 15 - 5PH , 17-4PH, and PH13-8Mo, which are used in applications

  8. T-Slide Linear Actuators

    NASA Technical Reports Server (NTRS)

    Vranish, John

    2009-01-01

    T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off

  9. Nuclear radiation actuated valve

    DOEpatents

    Christiansen, David W.; Schively, Dixon P.

    1985-01-01

    A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

  10. Application Actuation Trade Study

    DTIC Science & Technology

    1982-01-01

    Rectifier Unit 3 1..5 37.5 Battery 40 A-Hr 1 76 75 Battery Charger 1 6.8 6.8 Static Inverter I 12.C 13.C AC Power Pelay 3 PDT 1 1.2 1.2 AC Povmr Relay 3 PD)T...Weight 0.7 pounds Total Weight 4.7 pounds Both actuators are Vowered by 28V DC brush type motors so that the system can be operated from battery pover in... DC -AC Inverter 2 34 68 Battery (2 @ 4C A-Hr) 2 75 150 AC Power Contactor 6POT 2 18 36 AC Power Contactor 6PST 2 12 24 AC Power Contactor SPST 4 1

  11. Use of a composite Biomer-butyl rubber/Biomer material to prevent transdiaphragmatic water permeation during long-term, electrically-actuated left ventricular assist device (LVAD) pumping

    PubMed Central

    McGee, Michael G.; Szycher, Michael; Turner, Stephen A.; Clay, Warren; Trono, Ruben; Fuqua, John M.; Norman, John C.

    1980-01-01

    The pumping diaphragm of the Texas Heart Institute (THI) E-Type ALVAD must perform the dual functions of providing a flexible blood interface and isolating the electrical actuator from adjacent fluids. Thus, protection is required against fluid leakage and moisture diffusion to prevent corrosion and damage to electrical actuator components. Average diffusion rates up to 1 ml per day through currently used elastomeric diaphragm materials have been measured during static in-vitro and in-vivo tests. To circumvent this problem, an improved pumping diaphragm has been recently developed for use with the electrically-actuated THI E-Type ALVAD. This trilaminar diaphragm consists of a composite Biomer and butyl rubber design. A.010 inch layer of butyl rubber (characterized by an extremely low diffusion rate for water, ≃ 0 ml per day) is positioned between two Biomer layers (.020 and .010 inches in thickness). Initial invitro and in-vivo studies, in calves, indicate that this composite diaphragm provides an excellent barrier to water permeation, without sacrificing biocompatibility or structural integrity under conditions of chronic flexure. Images PMID:15216255

  12. Oxidation Protection for Thermocouples

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1984-01-01

    Thin platinum film on thermocouple sheath protects non-noble-metal thermocouples from deterioration in oxygen-rich atmosphere. Coating works on nickel-alloy sheathed thermocouples otherwise destroyed by corrosion in pure oxygen at 1,000 degrees C.

  13. Polypyrrole actuators for tremor suppression

    NASA Astrophysics Data System (ADS)

    Skaarup, Steen; Mogensen, Naja; Bay, Lasse; West, Keld

    2003-07-01

    Neurological tremor affecting limbs can be divided into at least 6 different types with frequencies ranging from 2 to about 20 Hz. In order to alleviate the symptoms by suppressing the tremor, sensing and actuation systems able to perform at these frequencies are needed. Electroactive polymers exemplify "soft actuator" technology that may be especially suitable for use in conjunction with human limbs. The electrochemical and mechanical properties of polypyrrole dodecyl benzene sulphonate actuator films have been studied with this application in mind. The results show that the time constants for the change of length and for the stiffness change are significantly different; the stiffness change being about 10 times faster. Both force measurements and Electrochemical Quartz Crystal Microbalance measurements indicate that the actuation process is complex and involves at least two different processes. The EQCM results make it possible to formulate a hypothesis for the two different time constants: Sodium ions enter the polymer correlated with a fast mass change that probably involves a few (~4) strongly bound water molecules as well. On further reduction, about 10 additional water molecules enter the polymer in a slower process driven by osmotic pressure. Earlier work has tended to focus on achieving the maximum length change, therefore taking the time needed to include all processes. However, since the slower process described above is associated with the lowest strength of the actuator, concentrating on the faster stiffness change results in only a small reduction in the work done by the actuator. This may make actuation at higher frequencies feasible.

  14. Actuator design using electroactive polymers

    NASA Astrophysics Data System (ADS)

    Fernandez, Diego; Moreno, Luis; Baselga, Juan

    2005-07-01

    In order to make EAP actuators technology scalable a design methodology for polymer actuators is required. Design variables, optimization formulas and a general architecture are required as it is usual in electromagnetic or hydraulic actuators design. This will allow the development of large EAP actuators from micro-actuator units, specifically designed for a particular application. It will also help to enhance the EAP material final performance. This approach is not new, since it is found in Nature. Skeletal muscle architecture has a profound influence on muscle force-generating properties and functionality. Based on existing literature on skeletal muscle biomechanics, the Nature design philosophy is inferred. Formulas and curves employed by Nature in the design of muscles are presented. Design units such as fiber, tendon, aponeurosis, and motor units are compared with the equivalent design units to be taken into account in the design of EAP actuators. Finally a complete design methodology for the design of actuators based on multiple EAP fiber/sheets is proposed. In addition, the procedure gives an idea of the required parameters that must be clearly modeled and characterized at EAP material level prior to attempt the design of complex Electromechanical Systems based on Electroactive Polymers.

  15. Gear-Driven Turnbuckle Actuator

    NASA Technical Reports Server (NTRS)

    Rivera, Ricky N.

    2010-01-01

    This actuator design allows the extension and contraction of turnbuckle assemblies. It can be operated manually or remotely, and is extremely compact. It is ideal for turnbuckles that are hard to reach by conventional tools. The tool assembly design solves the problem of making accurate adjustments to the variable geometry guide vanes without having to remove and reinstall the actuator system back on the engine. The actuator does this easily by adjusting the length of the turnbuckles while they are still attached to the engine.

  16. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, Douglas B.; Shahinpoor, Mohsen; Segalman, Daniel J.; Witkowski, Walter R.

    1993-01-01

    Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

  17. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, D.B.; Shahinpoor, M.; Segalman, D.J.; Witkowski, W.R.

    1993-10-05

    Electrically controlled polymeric gel actuators or synthetic muscles are described capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots. 11 figures.

  18. Low toxic corrosion inhibitors for aluminum in fresh water

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Combinations of chemical compounds that reportedly reduce the corrosion of aluminum in fresh water were evaluated. These included combinations of borates, nitrates, nitrites, phosphates, silicates, and mercaptobenzothiazole. Eight of fifty inhibitor combinations evaluated gave excellent corrosion protection and compared favorably with sodium chromate, which has generally been considered standard for many years.

  19. Corrosion in prestressed concrete: Pipes, piles, and decks

    SciTech Connect

    Szeliga, M.

    1995-12-31

    This is the first compilation or book focusing on prestressed concrete. It features 21 classic NACE papers on prestressed concrete piping, piles, bridge decks, and cathodic protection. It includes basic corrosion mechanisms of prestressed concrete structures with detailed case histories of corrosion failures and corrective measures.

  20. Shop fabricated corrosion-resistant underground storage tanks

    SciTech Connect

    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 over 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.