Ni42Cr6Fe合金在高温湿氢中的氧化膜组织结构及生长过程研究

用ＴＥＭ、Ｘ射线衍射、ＳＥＭ等技术研究了Ｎｉ４２Ｃｒ６Ｆｅ玻封合金在高温湿氢中的氧化膜生长过程。氧化初期，Ｃｒ＿（２）Ｏ＿３和尖晶石氧化物同时形核长大，前者在晶界处形核长大，后者在晶内处形核长大。随后由于Ｃｒ的选择氧化，氧化膜主要以Ｃｒ２Ｏ３生长为主．当氧化进行到一定程度后，由于表面层Ｃｒ的贫化，氧化膜生长转化以（Ｆｅ，Ｍｎ）Ｃｒ２Ｏ４尖晶石氧化物生长为主．最后形成表层以粗大晶粒（Ｆｅ，Ｍｎ）Ｃｒ２Ｏ４为主，底部以较小晶粒Ｃｒ２Ｏ３为主，中部由大晶粒（Ｆｅ，Ｍｎ）Ｃｒ２Ｏ４围绕小晶粒Ｃｒ２Ｏ３的稳态氧化膜组成

GROWTH AND STRUCTURE OF OXIDE FILM ON Ni42Cr6Fe ALLOY UNDER HIGH TEMPERATURE MOIST HYDROGEN

Structural studies of the growth of oxide film on the glass sealing alloy Ni42Cr6Fe under high temperature moist hydrogen atmosphere were observed by using SEM, TEM and X-ray diffraction techniques. At initial oxidizing stage. Cr2O3 and spinel (Fe, Mn) Cr2O4 were nucleated simultaneously. The former mainly grew intergranularly and the latter intragranularly. Then, the growth of oxide film was mainly of Cr2O3 due to the selective oxidation of Cr. As oxidation goes on to a certain extent. the surface Cr depletes and the growth of oxide film changes into spinel as majority. Finally. the coarse spinel (Fe, Mn)Cr2O4 will form at outer surface, the fine Cr2O3 grains in the bed and the coarse spinel around fine Cr2O3 will be matured in the middle part of oxide film.