Abstract In general support of planetary exploration missions, the chemical, structural and microstructural behavior of stainless steels 304 and 316 was probed after exposure to a gas mixture 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 9.2 × 106 Pa and 740 K for a duration of 10, 21, and 42 days. Stainless steel 304 and 316 samples were characterized before and after the experiment by gravimetric analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and cross-section electron microscopy analysis. All samples exposed to the Venusian atmosphere formed double-layered scales in which the outer layer is mainly magnetite (Fe3O4) and the inner layer is mainly spinel (Fe3-xCrxO4). Nickel sulfide and oxide formed at the interface of stainless steel 304. Nickel sulfide also formed in the inner and outer layer of the stainless steel 316 scale. Chromium carbide was only detected by Auger analysis at the interface of the unpolished side of the stainless steel 304 coupon sample. Stainless steel 304 with its smoother surface (780.62 nm total roughness on the polished side and 3.57 μm on the unpolished side) and slightly higher chromium and slightly lower nickel content, exhibited slower kinetics of oxidation (3.1 ± 0.5 × 10−3 mg cm−2 day−1) than stainless steel 316 (0.05 ± 0.07 mg cm−2 day−1) with its rougher surface (4.78 μm total roughness on both sides). The slightly higher molybdenum content in stainless steel 316 was also responsible for increasing its kinetics of oxidation because of the formation of molybdenum sulfide. Our thermodynamic calculations of the phase assemblage containing the Venus gas mixture and the stainless steel samples predicted hematite Cr2O3(s), Fe2O3(s), CrS(l), Cr2S3(l), NiS(l), FeS(l), CrO(l), H2(g), HCl(g), HF(g), NH3(g) and H2S(g) as the thermodynamically stable phases formed at the Venus atmospheric conditions.

中文翻译：

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304和316不锈钢在金星大气表面条件下的氧化行为

摘要 在行星探索任务的普遍支持下，不锈钢 304 和 316 在暴露于具有模拟金星低层大气的温度、压力和成分的气体混合物后，对其化学、结构和微观结构行为进行了探测。在 Glenn Extreme Environments Rig (GEER) 室中使用金星气体混合物（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 和 5 ppb HF）在 9.2 × 106 Pa 和 740 K 下持续 10、21 和 42 天。不锈钢304和316样品在实验前后通过重量分析、X射线衍射（XRD）、X射线光电子能谱（XPS）、俄歇电子能谱（AES）和横截面电子显微镜分析进行表征。所有暴露于金星大气的样品均形成双层鳞片，其中外层主要是磁铁矿（Fe3O4），内层主要是尖晶石（Fe3-xCrxO4）。304不锈钢的界面处形成硫化镍和氧化物。316不锈钢水垢的内外层也形成硫化镍。仅通过俄歇分析在不锈钢 304 试样未抛光面的界面处检测到碳化铬。不锈钢 304 表面更光滑（抛光面的总粗糙度为 780.62 nm，未抛光面的总粗糙度为 3.57 μm）和略高的铬和略低的镍含量，表现出较慢的氧化动力学（3.1 ± 0.5 × 10−3 mg cm− 2 day−1) 比不锈钢 316 (0.05 ± 0.07 mg cm−2 day−1) 更粗糙的表面 (4. 两侧总粗糙度为 78 μm）。由于硫化钼的形成，不锈钢 316 中钼含量稍高也是增加其氧化动力学的原因。我们对包含金星气体混合物和不锈钢样品的相组合的热力学计算预测赤铁矿 Cr2O3(s)、Fe2O3(s)、CrS(l)、Cr2S3(l)、NiS(l)、FeS(l)、CrO (l)、H2(g)、HCl(g)、HF(g)、NH3(g) 和 H2S(g) 作为在金星大气条件下形成的热力学稳定相。