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Results for “stainless steel corrosion”

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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Composite coatings from polycarbosilane derived SiC and Al/SiC cermet active fillers as protective barriers against steel corrosion

Stainless steel is used throughout the world as a structural material. However, it undergoes corrosion damage when exposed to extremely corrosive media, such as the marine environment. An alternative to solve this problem lies in the development of coatings that can withstand extreme conditions but also be easily deposited with inherently corrosion-resistant materials such as silicon carbide (SiC). The present study shows a simple method to produce Al/SiC cermet powders by attrition milling. The resulting cermet powders with a metallic matrix and hemispherical morphology, were employed as fillers in polycarbosilane (PCS) solutions that were sprayed on A304 stainless steel substrates. Al/SiC composite coatings were produced after heating the sprayed suspensions at 700 °C for 1 h in Ar atmosphere. The resulting composite coatings exhibited low surface energies (< 35 mN/m), water contact angles of 53°, and adhesion strength of up to 30 MPa. Finally, corrosion tests were performed in a cyclic corrosion test chamber, showing that these coatings effectively reduced the corrosion rate of stainless steel by 87%, reaching corrosion rate values of 0.007 g/cm 2 year.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Chemical Modeling of ATR Fuel in DOE Standard Canisters with Borated Stainless Steel Corrosion

Road-ready and final disposition packaging configurations for the ATR fuel dictates storage within helium backfilled sealed DOE standard canisters. The packaging configuration for the DOE canisters places 10 ATR elements within a Type 1a basket, and three baskets are loaded within each DOE canister. In order to provide a criticality control mechanism, these stainless baskets are proposed to be built with 1-2 weight percentage of boron. This report seeks to identify effects of corrosion of this basket material over time. The primary reaction found through surveying literature was the oxidation of the iron in steel by water to produce some hydrogen. This reaction was built into the previous chemical model of the DOE canister to assess additional hydrogen and pressure build up over time. Literature for non-borated stainless steel, and carbon steel has shown that irradiation increases the rate of corrosion, and it is assumed a similar effect would occur with borated stainless steel. Due to the wide range of results in literature, and the variation of the corrosion with boron content, a wide range of corrosion rates was tested in the model from 80 nm/yr up to 1800 nm/yr.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1985

The effects of surface pretreatment and nitrogen tetroxide purification on the corrosion rate of Type 304L stainless steel

Corrosion rates of 304L stainless steel coupons in MON-1 oxidizer have been measured as a function of cleaning procedures employed, surface layer positions, propellant impurity levels, and short-term exposure durations (14 to 90 days). Of special interest was propellant contamination by buildup of soluble iron, which may cause flow decay. Surface treatments employed were combinations of cleaning, pickling, and passivation procedures. Propellants used were MIL-SPEC MON-1 and several types of purified NTO (i.e., low water, low chloride) which may, at a later time, be specified as spacecraft grade. Pretest coupon surface analysis by X-ray photoelectron spectroscopy (XPS-ESCA) has revealed important differences, for the different cleaning procedures, in the make-up of the surface layer, both in composition and state of chemical combination of the elements involved. Comparisons will be made of XPS/ESCA data, for different cleaning procedures, for specimens before and after propellant exposure.

Blue, G. D.↗
DOE OSTI2023

Influence of Realistic, Cyclic Atmospheric Cycles on the Pitting Corrosion of Austenitic Stainless Steels

Pitting corrosion was evaluated on stainless steels 304H, 304, and 316L the surfaces of which had ASTM seawater printed on them as a function of surface roughness after exposure to an exemplar realistic atmospheric diurnal cycle for up to one year. Methods to evaluate pitting damage included optical imaging, scanning electron microscopy imaging, profilometry analysis, and polarization scans. The developed cyclic exposure environment did not significantly influence pitting morphology nor depth in comparison to prior static exposure environments. Cross-hatching was observed in a majority of pits for all material compositions with the roughest surface finish (#4 finish) and in all surface finishes for the 304H composition. Evidence is provided that cross-hatched pit morphologies are caused by slip bands produced during the grinding process for the #4 finish or by material processing. Additionally, micro-cracking was observed in pits formed on samples with the #4 surface finish and was greatly reduced or absent for pits formed on samples with smooth surface finishes. This suggests that both a low RH leading to an MgCl 2 -dominated environment and a rough surface containing significant residual stress are necessary for micro-cracking. Finally, the use of various characterization techniques and cross sectioning was employed to both qualitatively and quantitatively assess pitting damage across all SS compositions and surface finishes.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Enhanced crevice corrosion of stainless steel 316 by degradation of Cr-containing hollandite crevice former

This study explores the corrosion interactions between stainless steel 316 (SS316), a candidate nuclear waste canister material, and Cr-containing hollandite (Ba 1.15 Cr 2.3 Ti 5.7 O 16 ), a model ceramic nuclear waste form. The two materials were corroded in close proximity in 0.6 M NaCl solution at 90 °C for 28 days. Severe crevice corrosion was observed on the stainless steel surface after the corrosion experiment, which is likely associated with the rapid accumulation of Cr 3+ cations originating from both SS316 and the Cr-containing hollandite. Furthermore, the enhanced corrosion of SS316 by the corrosion products of hollandite is quantitatively explained using a classical crevice corrosion model.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Corrosion Testing Proposal -1: Assessment of the Corrosion of Stainless Steel Subjected to an Aqueous Solution of Hydrochloric Acid

This corrosion-test proposal outlines the methods to promote rapid pitting corrosion on various pitting resistant stainless steels under controlled conditions. This study can be performed in-whole or in- part as the Corrosion Working Group (CWG) leadership of the Los Alamos National Laboratory (LANL) deems pertinent. This proposal is in response to CWG’s need to understand the mechanisms and the possible detrimental failure of the 316L SAVY (an acronym that represents the first initial of the four co-developers, Stone, Anderson, Veirs, Yarbro) 4000 container design currently in service. This detrimental failure evolved from a question that the CWG arrived to by consensus as “What is the critical pit depth that would comprise the design wall-strength of the SAVY-4000?”

36 MATERIALS SCIENCE↗
DOE OSTI2022

Characterization of Contaminants and Mobility in WMA A-AX Boreholes D0006 and D0008

This study was initiated to determine if subsurface contaminants in the A-AX vadose zone at the Hanford site (boreholes D0006 and D0008) caused corrosion of nearby stainless steel well casings (299-E-24-19, 299-E25-46, and 299-E25-236) and, based on the type and distribution of contaminants, determine if contaminants are from one or more sources including a) the A-104 and/or A-105 tanks, b) the 242A evaporator, and c) the 200-E-286 ditch. A tiered approach was used for characterizing contaminants in vadose zone sediments starting with mobile and total contaminant concentrations (Tier 1), characterizing contaminant speciation (Tier 2), and measuring contaminant leaching (Tier 3). Total and mobile contaminant measurements at seven depths showed elevated sulfate and nitrate in all samples (130 to 280 ft depth), elevated chloride in five depths, and no elevated radionuclides except I-129 in D0006 at 206 to 208 ft depth. If these contaminants were initially acidic, stainless-steel corrosion would occur. However, because sediments likely have a high acid neutralization capacity, an acidic spill would have been neutralized within tens of feet, so casing corrosion would likely occur in shallow sediments. GEL labs data also shows low (but above natural) chromate from shallow to 170 ft depth, then higher chromate to 280 ft, suggesting a surface Cr spill or casing corrosion. GEL labs data also showed evidence of more than one plume, with deep nitrate, sulfate, and chloride migration, but only shallow tritium migration. Tritium should migrate nearly unretarded in the subsurface like nitrate and chloride. Elevated aqueous cations and anions in the D0006 206 to 208' depth pore water (SO 4 2- , NO 3 - , Na + , K + , Ca 2+ , Mg 2+ , Si) could be the result of acid disposal and calcite dissolution at shallow depth, with deeper migration of SO 4 2- , NO 3 - from acids and Ca 2+ and Mg 2+ from calcite. Elevated Si (160 mg/L) indicates dissolution of clays or other silicates, which can also occur in acids. Acid extractable metals did show elevated Cr (but not Fe, Ni, Mo, and Mn) above natural levels, which may indicate stainless-steel well corrosion or transport of metals from a shallow spill. The elevated I-129 in D0006 at 206 to 208' depth was low with 0.34 μg/g in pore water and 1.5 μg/g total extractable I-129 in the sediment, which indicates significant fraction of I-129 was bound in one or more precipitates. Although total I-129 was below detection limits in most extractions due to high molybdate interference, I-127 analysis provided some insight into potential precipitate phases. Total I-127 was mainly extracted by acetate or acetic acid (67%), which may be iodine in calcite. Inorganic carbon measurement identified 1.65% calcite, and total organic carbon (TOC) was below detection limits, so iodine was not associated with organic matter. Nearly all the I-127 was present as iodide. In 1-D leach experiments, I-127 as iodide leached from the sediment within 2 pore volumes. Due to high and dynamic molybdate leaching from the sediment and interference with I-129 analysis, there were few quantifiable I-129 measurements. The calculated molybdate release rates from the sediment suggested Mo was being released from the same precipitate phase, such as molybdate incorporated into calcite. Overall, because there was little radioactive contamination measured in D0006 and D0008 boreholes, potential releases from A-104 and A-105 did not reach this location south of the A tank farm. Elevated cations and anions found in D0006 and D0008 at depth as the result of acidic disposal could cause shallow stainless steel casing corrosion. The nearby 242A evaporator generally contained alkaline waste and tritium, but the nearby 200-E-286 ditch generally contained high Cl - liquid effluent, so these are unlikely to be acidic sources.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

Mechanistic transition of stainless steel 304L corrosion in MgCl 2 phase change material under thermal cycling

Magnesium chloride (MgCl 2 )-based molten salt phase change materials (PCMs) are promising candidates for thermal energy storage (TES) owing to their advantageous thermophysical properties, however, their high corrosivity in the molten state limits material compatibility. In this study, the corrosion behavior of 304?L stainless steel (SS304L) exposed to MgCl2 PCM was investigated as a function of thermal cycling (up to 9000 cycles) relevant to PCM-based TES systems. Microstructural changes and elemental redistribution at the alloy-salt interface under thermal cycling conditions were characterized using synchrotron-based X-ray fluorescence (XRF) and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS). Results show that corrosion is governed by selective Cr-dissolution and elemental diffusion near the interface and grain boundaries. A clear transition in the dominant corrosion mechanism is observed with increasing thermal cycles. Surface corrosion is the dominant mechanism up to 1000 cycles, whereas intergranular corrosion becomes the primary degradation mode beyond 2000 cycles. These mechanistic changes are interpreted in terms of evolving interfacial chemistry, microstructure and the diffusion-driven redistribution of alloying elements.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Ab initio Study of the Mechanism for the Initiation of Localized Corrosion on Stainless Steel

Stainless steels are widely used as primary piping material in PWR’s because of their high corrosion resistance largely due to the formation of a passive film of metal oxides, such as chromium (e.g., Cr2O3). However, upon exposure to aggressive ions like chlorides (Cl-), stainless steel becomes susceptible to localized corrosion due to the breakdown of the passive film. It is therefore essential to gain fundamental insights into the mechanism of the passive film breakdown (depassivation) to develop a tailored design to minimize localized corrosion. This project investigates the initial stages of the depassivation of the Cr passive film using density functional theory (DFT), a quantum based computational method.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Multiscale Development and Validation of the Stainless Steel Alloy Corrosion (SStAC) Tool for High Temperature Engine Materials

The goal of this project was to create a simulation tool to assist in part design, reducing costs by eliminating the need for conservative material selection, and enabling alloy optimization to improve corrosion resistance. Thus, it helps decrease costs for existing engines and assists in the material and engine design for the engines of the future. To meet our stated goal, we developed the Stainless-Steel Alloy Corrosion (SStAC) tool, which: (1) Models corrosion of engine valves fabricated from 21-2N valve steel in an engine environment at temperatures up to 800 °C. (2) Runs in 1D for a fast estimate of the corrosion rate, and in 2D or 3D for more detailed simulations that represent any part geometry and predict the precise location and rate of corrosion and its impact on the mechanical and thermal behavior. (3) Was implemented using the open-source Multiphysics Object Oriented Simulation Environment (MOOSE). (4) Couples the corrosion model with mechanics and thermal transport models. The SStAC tool can predict the corrosion rate of 21-2N engine valves with less than 10% error.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Viability of Cathodic Protection for Preventing Corrosion of Stainless Steel 316H in Molten LiF-NaF-KF

Molten fluoride salts are candidate heat transfer fluids in a number of applications such as generation IV molten salt nuclear reactors and concentrated solar power plants. However, a chief concern in the design of these systems is the corrosion of structural materials that come in contact with these molten salts. Redox control methods such as the purification of salt, the addition of active elements, and applied electrochemical potential can be efficient methods for preventing the corrosion of structural materials in molten fluoride salts. Applied electrochemical potential as a redox control method for application in molten fluoride salts has rarely been explored. This study seeks to understand the viability of impressed current cathodic protection (CP) at various currents as a redox control method to prevent corrosion of stainless steel 316H in molten LiF-NaF-KF (FLiNaK) salt. Results show that application of CP can be an effective method to prevent corrosion of SS316H in molten FLiNaK salt, but the applied current will have to be optimized to prevent undesirable side effects such as reduction of salt constituents, salt deposition on electrodes, etc.

Materials Science↗
DOE OSTI2022

Long-term interactive corrosion between International Simple Glass and stainless steel

The interactive corrosion between stainless steel 316 (SS) and International Simple Glass (ISG) has been studied for 12 months. The samples were placed in intimate contact to create crevice corrosion conditions on SS in a 0.6 M NaCl solution with and without 142 ppm dissolved silica species enriched in 29 Si. Corrosion on SS was observed with large pits located close to the crevice mouth at the end of 1 year in 0.6 M NaCl solution. The SS corrosion was also associated with the dissolution of nearby glass in a highly localized manner. When the leaching solution was saturated with silica species, the corrosion rate of SS was suppressed. However, the presence of SS enhances ISG dissolution in both conditions. The implications of the observed phenomena on the long-term storage of nuclear waste are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Pitting Corrosion in 316L Stainless Steel Fabricated by Laser Powder Bed Fusion Additive Manufacturing: A Review and Perspective

Abstract 316L stainless steel (316L SS) is a flagship material for structural applications in corrosive environments, having been extensively studied for decades for its favorable balance between mechanical and corrosion properties. More recently, 316L SS has also proven to have excellent printability when parts are produced with additive manufacturing techniques, notably laser powder bed fusion (LPBF). Because of the harsh thermo-mechanical cycles experienced during rapid solidification and cooling, LPBF processing tends to generate unique microstructures. Strong heterogeneities can be found inside grains, including trapped elements, nano-inclusions, and a high density of dislocations that form the so-called cellular structure. Interestingly, LPBF 316L SS not only exhibits better mechanical properties than its conventionally processed counterpart, but it also usually offers much higher resistance to pitting in chloride solutions. Unfortunately, the complexity of the LPBF microstructures, in addition to process-induced defects, such as porosity and surface roughness, have slowed progress toward linking specific microstructural features to corrosion susceptibility and complicated the development of calibrated simulations of pitting phenomena. The first part of this article is dedicated to an in-depth review of the microstructures found in LPBF 316L SS and their potential effects on the corrosion properties, with an emphasis on pitting resistance. The second part offers a perspective of some relevant modeling techniques available to simulate the corrosion of LPBF 316L SS, including current challenges that should be overcome.

Voisin, T. (ORCID:0000000287462659)↗