【摘要】 本工作研究了Ni-20Cr-Si和Ni-20Cr-Si-Al合金在1200℃空气中的氧化行为。测定并计算了合金氧化增重与时间的函数关系及抛物线氧化速率。用XRD和SEM-EMPA分析了合金氧化膜的组成与结构。探讨了合金元素硅和铝提高Ni-20Cr合金抗高温氧化性能的机理。更多还原

【Abstract】 The oxidation behavior of Ni-20Cr-Si and Ni-20Cr-Si-Al alloys at 1200℃ in air （Po₂=0.21atm） was investigated. The functional relations of isothermal weight gains vs oxidation time for the alloys were determined and the parabolic oxidation rates were calculated. The results showed that the oxidation rate of Ni-20Cr-Si-Al is lower than that of Ni-20Cr-Si, with the initial oxidation rate of the former being much lower. Composition and structures of the oxide scale of the alloys were analyzed with XRD and SEM-EMPA. The results indicated that the oxides （e. g. Ni₂SiO₄ and NiO·16Al₂O₃ etc.） of silicon and aluminium which are much more readily oxidizable than chromium tend to be located near the metal -oxide interface （in the lower oxygen pressure zone）, while outer layer of oxide scale is mainly composed of chromic oxide.更多还原