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Results for “CORROSION PROTECTION”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

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

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.

Mendrek, M. J.↗
NASA NTRS1991

Corrosion-protective coatings from electrically conducting polymers

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.

Thompson, Karen Gebert↗
DOE OSTI2017

Corrosion Protection of Phenolic-Epoxy/Tetraglycidyl Metaxylediamine Composite Coatings in a Temperature-Controlled Borax Environment

The failure behavior for two kinds of phenolic-epoxy/tetraglycidyl metaxylediamine composite coatings in 60 °C borax aqueous solution was evaluated using electrochemical methods (EIS) combined with scanning electron microscopy, confocal laser scanning microscope, water immersion test, and Raman spectrum. The main focus was on the effect of curing agent on the corrosion protection of coatings. Results revealed that the coating cured by phenolic modified aromatic amine possessed more compact cross-linked structure, better wet adhesion, lower water absorption (0.064 mg h{sup −1} cm{sup −2}) and its impedance values was closed to 10{sup 8} Ω cm{sup 2} after immersion for 576 h, while the coating cured by modified aromatic ring aliphatic amine was lower than 10{sup 5} Ω cm{sup 2}. The corrosion mechanism of the two coatings is discussed.

36 MATERIALS SCIENCE↗
NASA NTRS1982

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

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.

Spalvins, T.↗
DOE OSTI2023

Mechanistic origins of corrosion protection of aluminum alloys by graphene/polyetherimide nanocomposite coatings

Light-weighting vehicular components through adoption of light-metal structural alloys holds promise for reducing the fuel consumption of internal combustion engine vehicles and increasing the range of battery electric vehicles. However, the alloyed microstructure and surface precipitates of aluminum alloys render these materials susceptible to corrosion under modest excursions from neutral pH. Traditional chromium-based anodic passivation layers are subject to increasingly stringent environmental regulations, whereas options for sacrificial cathodic films are sparse for electropositive metals. While hybrid nanocomposite coatings have shown initial promise, mechanistic underpinnings remain poorly understood. Here, a fully imidized polyetherimide (PEI) resin is utilized as the continuous phase with inclusion of unfunctionalized exfoliated graphite (UFG). A comprehensive investigation of the mechanisms of corrosion protection reveals key fundamental design principles underpinning corrosion inhibition. First, strong interfacial adhesion, which for PEI is facilitated by binding of imide carbonyl moieties to Lewis acidic sites on Al surfaces. Second, the miscibility of ion-impervious nanoscopic UFG fillers and stabilization of a substantial interphase region at UFG/PEI boundaries that result in minimizing the free volume at the filler/polymer interface. Finally, extended tortuosity of ion diffusion pathways imbued by the below-percolation-threshold 2D fillers. These three design principles help govern and modulate ion transport from electrolyte/coating interfaces to the coating/metal interface and are crucial for the extended preservation of barrier properties. The results suggest an approach to systematically activate multiple modes of corrosion inhibition through rational design of hybrid nanocomposite coatings across hard-to-abate sectors where light metal alloys are likely to play an increasingly prominent role.

36 MATERIALS SCIENCE↗
NASA NTRS2016

Smart Coatings for Corrosion Protection

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.

Coatings↗
DOE OSTI2018

Corrosion Evaluation of CoCrFeMnNi High-Entropy Alloys (HEAs) for Corrosion Protection of Natural Gas Transmission Pipelines

High-entropy alloys (HEAs), are multicomponent alloys composed of at least five elements with compositions of 5-35 atomic % for each element. These alloys are being investigated for corrosion protection of natural gas transmission pipelines by studying their behavior under aqueous acidic conditions. Electrochemical and immersion experiments were carried out in 3.5 weight % NaCl solution at pH 4 and 40°C. Oxygen was purged out from the solution by using CO2 as stripping gas. The electrochemical experiments included potentiodynamic and electrochemical impedance spectroscopy tests, used to calculate corrosion rates. Potentiodynamic polarization curves, including cyclic voltammograms, were used to explain active, active-passive, and passive regions of these alloys and susceptibility to localized corrosion. Surface characterization of the corroded samples were performed using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The results of the immersion and electrochemical testing indicate that some of the HEAs have better corrosion performance than commercial alloys UNS N10276, UNS K03014, and UNS 31600.

03 NATURAL GAS↗
DOE OSTI2022

Laser Surface Processing of Alloys for Corrosion Protection (Final Project Report of Marine Energy Seedling Project)

This is the final project report for the MHK Seedling project. The report describes use of laser surface processing (LSP) to modify the surface of test materials (Al, steel) and the corrosion testing performed on the resulting samples in different corrosion environments. Data shows that LSP improved the corrosion resistance of Al and steel used in this work relative to respective non-LSP samples. The data also showed that each material had a specific range of laser processing conditions where the beneficial effects of LSP (i.e. improvement in corrosion protection) were observed. Application of LSP to enable low-cost materials in marine environments, additional microstructural analysis and long-term testing are proposed to further develop this technology for marine renewable energy and systems.

36 MATERIALS SCIENCE↗
DOE OSTI2016

HVOF Thermal Spray TiC/TiB 2 Coatings for AUSC Boiler/Turbine Components for Enhanced Corrosion Protection

The high temperatures of operations still pose significant risk of degradation and fatigue from oxidizing, corroding and eroding environment. In addition to unused O 2 , water from combustion and SO x 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 (K 1C ~12 MPam 1/2 ) and excellent corrosion resistance (kp~1.9X10 -11 g 2 /cm 4 /s at 800°C in air). The overarching aim of the research endeavor was to synthesize oxidation, corrosion and wear resistant TiC and TiB 2 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.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1997

The Corrosion Protection of Magnesium Alloy AZ31B

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.

Danford, M. D.↗
DOE OSTI2021

Novel Magnesium Pretreatment Coatings Offering Excellent Corrosion Protection

There is a growing interest in using magnesium alloys for automotive, industrial, and aerospace applications due to their low density, high strength-to-weight ratio, good machinability, and low cost. These alloys have the potential to lighten cars and aircraft, reducing fuel consumption and emissions. A major drawback to the use of magnesium alloys is their highly reactive nature, which can result in corrosion; as a result, most existing pretreatment systems for these alloys require the use of chromium, which is increasingly coming under regulatory pressures, as a corrosion inhibitor. Through a project funded by the Department of Energy and administered by the U.S. Automotive Materials Partnership (USAMP), PPG developed chromium-free metal pretreatment solutions for ZEK-100 and AZ21 magnesium alloys. In a major technical advance, several chromium-free cleaning and pretreatment processes were developed that offer excellent corrosion protection when compared to a typical automotive pretreatment systems. To expand the use cases for these systems beyond single-alloy substrates to broader multi-metal assemblies, these pretreatment solutions were also optimized for use in multi-metal applications: compatibility with magnesium and other metals was demonstrated without the need for additional process steps.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Novel Magnesium Pretreatment Coatings Offering Excellent Corrosion Protection

There is a growing interest in using magnesium alloys for automotive, industrial, and aerospace applications due to their low density, high strength-to-weight ratio, good machinability, and low cost. These alloys have the potential to lighten cars and aircraft, reducing fuel consumption and emissions. A major drawback to the use of magnesium alloys is their highly reactive nature, which can result in corrosion; as a result, most existing pretreatment systems for these alloys require the use of chromium, which is increasingly coming under regulatory pressures, as a corrosion inhibitor. Through a project funded by the Department of Energy and administered by the U.S. Automotive Materials Partnership (USAMP), PPG developed chromium-free metal pretreatment solutions for ZEK-100 and AZ21 magnesium alloys. In a major technical advance, several chromium-free cleaning and pretreatment processes were developed that offer excellent corrosion protection when compared to a typical automotive pretreatment systems. To expand the use cases for these systems beyond single-alloy substrates to broader multi-metal assemblies, these pretreatment solutions were also optimized for use in multi-metal applications: compatibility with magnesium and other metals was demonstrated without the need for additional process steps.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Influence of Temperature Variation on the Formation and Corrosion Protective Performance of Calcium Carbonate Deposits in Artificial Seawater

The aim of this research was to investigate the influence of temperature variation on the formation and protective behavior of calcium carbonate scale deposited on steel electrodes in artificial seawater. Chronoamperometry measurement, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) and x-ray diffraction (XRD) were employed for analysis. An increase in temperature from 20 to 50 °C accelerated the oxygen reduction reaction, which increased the nucleation/deposition rate. The chronoamperometry, SEM and XRD results indicated that complete coverage of the electrode surface was achieved at higher temperatures because a denser layer of scale deposits covered the entire surface of the metal and acted as a barrier against the passage of oxygen. The EIS results showed that better corrosion protection was obtained after deposition that included a stepwise decrease in temperature, indicating fewer pathways through the deposited layer onto the electrode surface.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Correlation between Antimicrobial Activity and Bioactivity of Na-Mica and Na-Mica/Fluorapatite Glass and Glass-Ceramics and Their Corrosion Protection of Titanium in Simulated Body Fluid

The improvement in bioactivity of titanium (Ti) surface was achieved via coating it with Na-mica and Na-mica/fluorapatite glass and glass-ceramic using the low-cost electrophoretic deposition technique. Two compositions from pure Na-mica (M) and 80 Na-mica/20 fluorapatite glasses (MF) were prepared in the system SiO{sub 2}-Al{sub 2}O{sub 3}-MgO-MgF{sub 2}-Na{sub 2}O-B{sub 2}O{sub 3} using melting–quenching technique. Characterization of the as-prepared glasses and their counterpart glass-ceramics was studied using differential thermal analysis (DTA), x-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform-IR (FTIR) spectroscopy techniques. The bioactivity behavior was proved by studying the XRD, FTIR and SEM after immersing both glass and glass-ceramic samples in simulated body fluid (SBF). Both M and MF glasses and glass-ceramics showed high microhardness measurements and good antibacterial behavior. In vitro biodegradation was studied by using electrochemical corrosion behavior of the prepared glass- and glass-ceramic-coated Ti in SBF. The prepared coated Ti showed good corrosion resistance in SBF at 37 °C using potentiodynamic polarization technique, and the impedance data fitting explained the structure of the coating and the adsorption of SBF ions on the Ti surface. The MFGC provides the best corrosion-resistant coating, especially after sintering it.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Open-air plasma-assisted deposition of organosilicon coating for corrosion protection of AZ91D Mg alloy

As a corrosion barrier layer, open-air plasma-assisted organosilicon coating was applied on AZ91D Mg alloy. Organosilicon-coated AZ91D samples, prepared from two different plasma coating processes, were used for corrosion evaluation based on multistep electrochemical and H 2 collection measurements in 3.5 wt% sodium chloride (NaCl) solution. Some coated AZ91D samples were characterized with and without corrosion exposure in NaCl solution using electron microscopies and X-ray chemical analysis techniques. Further, the results indicate that the organosilicon coatings from open-air plasma processes are effective to delay the initiation of corrosion attack and also reduce the corrosion rate for AZ91D substrate. The corrosion attack was considered to develop after permeation of NaCl solution through the coating layer.

36 MATERIALS SCIENCE↗