NASA LogoNTRSNTRS - NASA Technical Reports ServerSearchmore_vertCollectionsAboutNewsHelpLogin Back to ResultsChemical and Microstructural Changes in Metallic and Ceramic Materials Exposed to Venusian Surface ConditionsThe chemical and microstructural behavior of steels (304, 310, 316, and 1018), nickel-based alloys (beta-NiAl, G30, and 625), gold, coatings (4YSZ, SilcoNert(TradeMark) 1040 (SilcoTek Co.), Dursan(TradeMark) (SilcoTek Co.), and porcelain), and bulk ceramics (alpha-Al2O3, fused quartz, beta-SiC, and alpha-Si3N4) were probed after exposure to supercritical fluid with temperature, pressure, and composition mimicking the Venus lower atmosphere. Exposures were carried out in the Glenn Extreme Environments Rig (GEER) chamber with the Venusian gas mixture (96.5% CO2, 3.5% N2, 30 ppm H2O, 150 ppm SO2, 28 ppm CO, 15 ppm OCS, 3 ppm H2S, 0.5 ppm HCl, and 5 ppb HF) at 92 bar (1330 psi) and 467 C (873 F) for durations of 10 and 42 days. An additional 21-day exposure was done to stainless steel uncoated and coated with SilcoNert(TradeMark) and Dursan(TradeMark). Samples were characterized before and after the experiment by gravimetric analysis, X-ray diffraction, X-ray photoelectron and Auger electron spectroscopies, and cross section electron microscopy analysis. All steels exposed for 10 and 42 days formed double-layered scales consisting mainly of metal (Cr, Fe, Ni) oxides and sulfides showing different chemistry, microstructure, and crystalline phases. The alloys G30 and 625 formed double-layered scales consisting mainly of nickel sulfides. After 10 days, the beta-NiAl exhibited no detectable scale, suggesting only a very thin film was formed. The 304 and 316 stainless steels coated with 4YSZ that were exposed for 10 and 42 days exhibited no significant oxidation. Steel 1018 coated with 4YSZ exhibited a corrosion scale of iron and/or chromium oxide formed at the base of the alloy. The 304 steel coated with porcelain did not exhibit corrosion, although the coating exhibited recession. SilcoNert(TradeMark) exposed for 10 and 42 days exhibited recession, although no oxidation was found to occur at the base of the alloy. Stainless steel 316 coated with Dursan(TradeMark)  exhibited corrosion at the base of the alloy. All ceramics tested showed no clear evidence of reaction. The weight-gain-per-area performance of the materials exposed in the GEER for 10 and 42 days are reported from the lowest to the highest weight gain per area as follows: gold did not exhibit any weight change; nickel-based alloys: beta- NiAl < G30 < 625; steels: 304 < 310 < 316 < 1018; ceramics: considering the experimental uncertainties, no weight change was observed for all ceramics of this work (alpha-Al2O3, Si3N4, SiC, and amorphous SiO2).Document ID20170006025Acquisition SourceGlenn Research CenterDocument TypeTechnical Memorandum (TM)AuthorsCosta, Gustavo C. C.*(Vantage Partners, LLC Cleveland, OH, United States)*Jacobson, Nathan S.*(NASA Glenn Research Center Cleveland, OH, United States)*Lukco, Dorothy*(Vantage Partners, LLC Cleveland, OH, United States)*Hunter, Gary W.*(NASA Glenn Research Center Cleveland, OH, United States)*Nakley, Leah*(NASA Glenn Research Center Cleveland, OH, United States)*Radoman-Shaw, Brandon G.*(Case Western Reserve Univ. Cleveland, OH, United States)*Harvey, Ralph P.*(Case Western Reserve Univ. Cleveland, OH, United States)*Date AcquiredJuly 3, 2017Publication DateJune 1, 2017Subject CategoryChemistry And Materials (General)Metals And Metallic MaterialsNonmetallic MaterialsReport/Patent NumberE-19325GRC-EDAA-TN37489NASA/TM-2017-219437Funding Number(s)CONTRACT_GRANT: NNC12BA01BDistribution LimitsPublicCopyrightPublic Use Permitted.Available DownloadsNameType20170006025.pdfSTIcloud_downloadcontent_copyvisibilityRelated RecordsThere are no records associated with this record.visibility_offNo Preview Available
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