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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Corrosion-Resistant Coatings on Spent Nuclear Fuel Canisters to Mitigate and Repair Potential Stress Corrosion Cracking (FY22 Status)

This report summarizes the activities performed by Sandia National Laboratories in FY22 to identify and test coating materials for the prevention, mitigation, and/or repair of potential chloride-induced stress corrosion cracking in spent nuclear fuel dry storage canisters. This work continues efforts by Sandia National Laboratories that are summarized in previous reports in FY20 and FY21 on the same topic. The previous work detailed the specific coating properties desired for application and implementation to spent nuclear fuel canisters (FY20) and identified several potential coatings for evaluation (FY21). In FY22, Sandia National Laboratories, in collaboration with four industry partners through a Memorandum of Understanding, started evaluating the physical, mechanical, and corrosion-resistance properties of 6 different coating systems (11 total coating variants) to develop a baseline understanding of the viability of each coating type for use to prevent, mitigate, and/or repair potential stress corrosion on cracking on spent nuclear fuel canisters. This collaborative R&D program leverages the analytical and laboratory capabilities at Sandia National Laboratories and the material design and synthesis capabilities of the industry collaborators. The coating systems include organic (polyetherketoneketone, modified polyimide/polyurea, modified phenolic resin), organic/inorganic ceramic hybrids (silane-based polyurethane hybrid and a quasi-ceramic sol-gel polyurethane hybrid), and hybrid systems in conjuncture with a Zn-rich primer. These coatings were applied to stainless steel coupons (the same coupons were supplied to all vendors by SNL for direct comparison) and have undergone several physical, mechanical, and electrochemical tests. The results and implications of these tests are summarized in this report. These analyses will be used to identify the most effective coatings for potential use on spent nuclear fuel dry storage canisters, and also to identify specific needs for further optimization of coating technologies for their application on spent nuclear fuel canisters. In FY22, Sandia National Laboratories performed baseline testing and atmospheric exposure tests of the coating samples supplied by the vendors in accordance with the scope of work defined in the Memorandum of Understanding. In FY23, Sandia National Laboratories will continue evaluating coating performance with a focus on thermal and radiolytic stability.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1979

X-ray photoelectron spectroscopy study of nickel and nickel-base alloy surface alterations in simulated hot corrosion conditions with emphasis on eventual application to turbine blade corrosion

Research on the high temperature oxidation and Na2SO4 induced hot corrosion of some nickel base superalloys was accomplished by using ESCA to determine the surface composition of the oxidized or corroded samples. Oxidation was carried out at 900 or 1000 C in slowly flowing O2 for samples of B-1900, NASA-TRW VIA, 713C, and IN-738. Oxidation times ranged from 0.5 to 100 hr. Hot corrosion of B-1900 was induced applying a coating of Na2SO4 to peroxidized samples, the heating to 900 C in slowly flowing O2. For oxidized samples, the predominant type of scale formed by each superalloy was determined, and a marked surface enrichment of Ti was found in each case. For corroded samples, the transfer of significant amounts of material from the oxide layer to the surface of the salt layer was observed to occur long before the onset of accelerating weight-gain. Changes in surface composition were observed to coincide with the beginning of accelerating corrosion, the most striking of which was a tenfold decrease in the sulfur to sodium ration and an increase in the Cr(VI) ratio.

Mateescu, G. D.↗
DOE OSTI2019

Passivation of a Corrosion Resistant High Entropy Alloy in Non-oxidizing Sulfate Solutions

The passivation behavior of a novel high entropy alloy (HEA) of composition 38Ni-21Cr-20Fe-13Ru-6Mo-2W at.% (33Ni-16Cr-17Fe-19Ru-9Mo-6W wt.%) was investigated in sulfate solutions of various pH levels. The HEA was compared to a commercially available Ni-Cr-Mo-W-Fe alloy, C-22. Experiments were conducted using in-situ electrochemical and ex-situ surface-sensitive methods to probe the growth and dissolution of the passive layer. The HEA exhibited excellent corrosion resistance in highly acidic and highly alkaline solutions, maintaining passivity through a broad range of potentials below the Cr transpassivity range. Extremely rapid and efficient oxide formation and lower quasi-steady passive current densities were observed during oxide growth in the passive range compared to commercial alloy C-22. Ex-situ characterization of the passive film by atom probe tomography and X-ray photoelectron spectroscopy provided insight into the oxide composition, thickness, and elemental valence states of potentiostatically-grown and air-formed oxides. All elements in the alloy were oxidized following potentiostatic oxide growth. Instead of distinct stoichiometric and phase-distinct oxides, a disordered solid solution oxide was observed with significant enrichment in Cr and Ru with the latter depending sensitively on potential, as well as depletion of Fe and Ni. Enrichment of Cr was modeled with a modified surface enrichment model. The oxide thickness was estimated to be 3-4 nm thick. The connection between the enrichment of Cr in the passive layer, Mo and W presence, and excellent passivity is discussed.

corrosion, High entropy alloys, XPS, atom probe to↗
DOE OSTI2017

Stress corrosion crack initiation of alloy 600 in PWR primary water

Stress corrosion crack (SCC) initiation of three mill-annealed (MA) alloy 600 heats in simulated pressurized water reactor primary water has been investigated using constant load tests equipped with in-situ direct current potential drop (DCPD) measurement capabilities. SCC initiation times were greatly reduced by a small amount of cold work. Shallow intergranular (IG) attack and/or cracks were found on most high-energy grain boundaries intersecting the surface with only a small fraction evolving into larger cracks and IGSCC growth. Crack depth profiles were measured and related to DCPD-detected initiation response. Processes controlling the SCC initiation in MA alloy 600 are discussed. IN PRESS, CORRECTED PROOF, 05/02/2017 - mfl

alloy↗
DOE OSTI2016

Understanding of corrosion mechanisms after irradiation: effect of ion irradiation of the oxide layers on the corrosion rate of M5 - 2016-0081

Irradiation damage in fuel cladding material is mainly caused by the neutron flux that results from fission reactions occurring in the fuel. To avoid the constraints inherent in handling radioactive material, the irradiation effects on the corrosion resistance of zirconium alloys can be studied by irradiating the materials with ions. We performed an original experiment using ion irradiation to more specifically study the influence of irradiation damage in the oxide on the corrosion rate of M5{sup R}. It has been established that irradiation with a 1.3-MeV helium ion at a fluence of 10{sup 17} cm{sup -2} results in significant modifications of oxide properties, oxygen diffusion flux, and oxidation kinetics, as evidenced by Raman spectroscopy, secondary ion mass spectrometry (SIMS) analyses, and measurements of mass gains. A newly identified Raman vibration band at 712 cm{sup -1} was linked to the presence of irradiation defects and allowed the evolution of their concentrations to be followed. The oxygen diffusion flux was significantly reduced after irradiation partly due to a surface concentration decrease of oxygen. The defects remained present in the oxide after 100 days of annealing in pressurized water reactor (PWR) conditions and were thus very stable in PWR conditions, which probably means that these defects would be stable in the reactor. According to the kinetics and in agreement with the results obtained by SIMS analyses, the oxidation rate was significantly reduced after ion irradiation, and this effect remained beyond 100 days in agreement with the high stability of irradiation defects in PWR conditions. An original model described quite well the oxidation kinetic results. (authors)

36 MATERIALS SCIENCE↗
DOE OSTI2022

Optimizing the Operational Parameters of an Electrochemical Purification Cell for Corrosion Mitigation in CSP Plants During Operation: Preprint

To make concentrating solar power (CSP) cost-competitive, the next generation of CSP plants will increase efficiency by operating at a higher temperature, which will require a new thermal energy storage material. One option for the thermal energy storage material is a ternary chloride salt that is stable at the temperatures required, but reacts easily with the atmosphere to form MgOHCl, a corrosive impurity. If left unchecked, this impurity will corrode the containment alloys, potentially leading to dangerous spills. We are working to design an electrochemical purification cell to remove MgOHCl from the molten chloride salt during CSP plant operation. In this paper, we use predictive modeling to assess the rate at which purification must occur. Additionally, we analyze possible process flow pathways for the molten chloride salts. Ultimately, we determine that implementation of a single reactor through which all chloride salts flow is the most efficient design to reduce impurity concentration below 0.1 mol % impurity.

concentrating solar power↗
NASA NTRS2017

Natural Environment Corrosion Testing at the Kennedy Space Center Beachside Atmospheric Corrosion Test Site

This presentation will provide an overview of how NASA has been conducting corrosion testing in the Natural Marine Environment at the Kennedy Space Center, Florida, U.S. The following questions will be addressed: What factors should be considered when selecting and constructing a test site? What are the attributes of a good test site? Is more severe always better? What environmental parameters should be monitored? How frequently? What factors should be considered when designing test specimens? Are current test standards sufficient? How do diurnal, annual and other fluctuations in corrosivity influence tests? How are test results interpreted? Can they be quantified?

Corrosion↗
DOE OSTI2017

Development of New Corrosion-Resistant Bimetals with Increased Corrosion Resistance Prepared by Electroslag Surfacing Technology

Results are presented for research in the development of new grades of corrosion-resistant steels for a bimetal cladding layer prepared by electroslag surfacing technology. It is shown that steel of transition martensiticaustenitic class may surpass martensitic steels both with respect to reliability characteristics and wear resistance. In this case, these steels have a more economic alloying system, and correspondingly low cost compared with austenitic chromium-nickel steels. Based on thermodynamic modeling of regions for phase existence optimum steel alloying systems are determined for new grades as a bimetal cladding layer. Results are presented for research in the development of new grades of corrosion-resistant steels for a bimetal cladding layer prepared by electroslag surfacing technology. It is shown that steel of transition martensiticaustenitic class may surpass martensitic steels both with respect to reliability characteristics and wear resistance. In this case, these steels have a more economic alloying system, and correspondingly low cost compared with austenitic chromium-nickel steels. Based on thermodynamic modeling of regions for phase existence optimum steel alloying systems are determined for new grades as a bimetal cladding layer.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Cold Spray Deposition of 304L Stainless Steel to Mitigate Chloride-Induced Stress Corrosion Cracking in Canisters for Used Nuclear Fuel Storage

A feasibility study of the cold spray deposition process of 304L stainless steel on 304L stainless steel substrates as a mitigation method for chloride-induced stress corrosion cracking (CISCC) has been investigated under various substrate conditions. The study is aimed at the application of this technology to mitigate CISCC that may potentially occur in or nearthe fusion welded regions of stainless steel canisters in Dry Cask Storage System (DCSS) for used nuclear fuels. Spherical gas-atomized 304L stainless steel powder, in the size range of 25 µm to 44 µm, was used as a feedstock powder for the cold spray process. The powder was deposited on four types of 304L substrates with various surface conditions: as-polished, oxidized, cold-rolled, plates with prototypical CISCC. The effects of cold spray parameters on quality of cold spray coatings were investigated. Thickness, porosity, and phases in the as-deposited materials were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and correlated with microhardness and adhesion strength measured via micro-indentation and ASTM C633 pulling test, respectively. XRD analysis of the coatings was also conducted to examine the effects of cold spray condition on residual stress state in the coating. Detailed cross-sectional examination of coating/substrate interfaces was performed with transmission electron microscopy (TEM) equipped with energy dispersive spectroscopy (EDS). Dense and continuous coatings with good adhesion strength and hardness were produced for the various substrate conditions by adjusting cold spray parameters. The results demonstrate that cold spray stainless steel coating is a viable option to provide a physical barrier against CISCC in fusion weld regions of stainless steel in corrosive chloride salt-bearing environments.

Dry Cask Storage Systems, cold spray, 304L stainle↗
DOE OSTI2020

Surface-Activated Corrosion in Tin–Lead Halide Perovskite Solar Cells

Mixed tin–lead halide perovskite solar cells have promising power conversion efficiencies, but long-term stability is still a challenge. Here, we examine the stability of a 60:40 tin–lead perovskite to better understand diminished device performance upon thermal treatment, both in ambient and inert atmosphere. Operando X-ray diffraction shows a stable bulk structure of the perovskite absorber, leading to the hypothesis that surface chemistry dominates the degradation mechanism. X-ray photoelectron spectroscopy reveals two new observations post-thermal annealing that accompany previously reported Sn 4+ evolution: (i) the formation of I 3 – intermediates preceding I 2 loss at the surface and (ii) evidence of under-coordinated tin and lead surface sites (Sn δ<2+ and Pb δ<2+ , respectively) in inert and ambient conditions. These two species indicate an activated corrosion (i.e., both oxidation and reduction) process at the surface as a possible chemical pathway for degradation, which is expected to be accelerated under operando voltage and light biases.

14 SOLAR ENERGY↗
DOE OSTI2016

Patterning corrosion-susceptible metallic alloys for digital image correlation in a scanning electron microscope: Patterning corrosion susceptible alloys for SEM-DIC

Here we investigate the self-assembly of gold nanoparticles on the surface of magnesium functionalized with 3-(aminopropyl)trimethoxysilane or 3-(mercaptopropyl)trimethoxysilane. These nanoparticles served as a speckle pattern for high magnification deformation tracking via digital image correlation combined with scanning electron microscopy. Controlling the pH of the gold nanoparticle suspension to a specific basicity passivated corrosion in magnesium and in three of its alloys to enable proper nanoparticle bonding and self-assembly. Magnesium was used as a model material as it is particularly difficult to modify for self-assembly because of its propensity to quickly form a thick oxide, hydroxide, and carbonate layer in the presence of oxygen, water, and carbon dioxide, respectively. Moreover, it corrodes in acidic and slightly basic solutions, further complicating the self-assembly process. Due to these difficulties, the successful self-assembly of nanoparticles on magnesium has not previously been reported, to the best of the authors' knowledge. This technique is potentially amendable to other corrosion-susceptible materials. Gold nanoparticles were self-assembled in a uniformly dispersed random distribution on pure cast magnesium, cast AM60 (Mg-6Al-0.5Mn), rolled WE43 (Mg-4Y-3Nd/Gd), and extruded ZE20 (Mg-2Zn-0.2Ce).

36 MATERIALS SCIENCE↗
DOE OSTI2023

Corrosion-Resistant Coatings on Spent Nuclear Fuel Canisters to Mitigate and Repair Potential Stress Corrosion Cracking (FY23 Status)

This report summarizes the activities performed by Sandia National Laboratories in FY23 to identify and test coating materials for the prevention, mitigation, and/or repair of potential chloride-induced stress corrosion cracking in spent nuclear fuel dry storage canisters. This work continues efforts by Sandia National Laboratories that are summarized in previous reports from FY20 through FY22 on the same topic. In FY23, Sandia National Laboratories, in collaboration with five industry partners through a memorandum of understanding, evaluated the physical, mechanical, and corrosion-resistance properties of eight different coating systems. The evaluation included thermal and radiation environments relevant to various time periods of storage for spent nuclear fuel canisters. The coating systems include polymeric (polyetherketoneketone, modified polyimide/polyurea, modified phenolic resin, epoxy), organic/inorganic ceramic hybrids (silane-based polyurethane hybrid and a quasi-ceramic sol-gel polyurethane hybrid), and coatings utilizing a Zn-rich primer applied to stainless steel coupons. The results and implications of these tests are summarized in this report. These analyses will be used to identify the most effective coatings for potential use on spent nuclear fuel dry storage canisters and to identify specific needs for further optimization of coating technologies for application on spent nuclear fuel canisters.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗