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用硫酸钠沉积法研究了四种镍基合金-Ni-16Cr,Ni-16Cr-2Nb,IN738和537合金-在900～1000℃之间的热腐蚀行为。用热天平测量了热腐蚀动力学曲线,用金相、SEM、电子探针、X 射线衍射和~(3δ)S 示踪法观察和分析了腐蚀产物。研究发现,Ni-16Cr-2Nb 合金中的铌富集在表面氧化膜内,形成 NaNbO_3而降低熔盐中的 O~(2-)浓度,抑制 Cr_2O_3膜与熔盐的反应;但在复杂成份的合金中。铌的上述作用可能促进氧化膜的酸性熔融。鈪同时能促进硫在 Ni-16Cr-2Nb 变形合金晶界上的连续分布,加速内硫化过程。
The corrosion behavior of four Ni-based alloys-Ni-16Cr, Ni-16Cr-2Nb, IN738 and 537 alloys at 900 ~ 1000 ℃ was investigated by sodium sulfate deposition method. The hot corrosion kinetics curve was measured by thermobalance, and the corrosion products were observed and analyzed by metallography, SEM, electron probe, X-ray diffraction and ~ (3δ) S tracing method. It is found that niobium is enriched in the surface oxide film in Ni-16Cr-2Nb alloy to form NaNbO_3 and reduce the concentration of O_2 in the molten salt, which inhibits the reaction of the Cr_2O_3 film with the molten salt. However, Alloy. The above action of niobium may promote the acidic melting of the oxide film. At the same time, it can promote the continuous distribution of sulfur on the grain boundary of Ni-16Cr-2Nb deformed alloy and accelerate the internal vulcanization process.