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通过静态氧化法研究了Cr20Ni80电热合金在空气中电加热到1 200℃的恒温氧化行为。使用无纸记录仪记录了Cr20Ni80合金两端电流电压的变化,扫描电镜(SEM)、X射线衍射仪(XRD)分析研究了氧化60、120h的氧化膜表面与截面形貌、表面氧化膜的相组成以及氧化层中元素分布情况。结果表明,Cr20Ni80合金在1 200℃下的氧化过程符合氧化过程的三阶段理论。氧化60h正处于氧化的第二阶段,氧化产物区分为三层,最外层主要包括NiO与NiCr_2O_4,中间层为Cr_2O_3,最内层为SiO_2内氧化层,其中最外层基本剥落。氧化120h为氧化的第三个阶段初期,此时,氧化膜剥落严重,Cr20Ni80合金丝即将断裂。
The static oxidation behavior of Cr20Ni80 electric alloy in air heated to 1 200 ℃ was studied by static oxidation method. The change of current and voltage across the Cr20Ni80 alloy was recorded by using a paperless recorder. The surface and cross-sectional morphology of the oxide film after 60 and 120h oxidation were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) Composition and the distribution of elements in the oxide layer. The results show that the oxidation process of Cr20Ni80 alloy at 1 200 ℃ accords with the three-stage theory of oxidation process. Oxidation 60h is in the second stage of oxidation, the oxidation product is divided into three layers, the outermost layer mainly includes NiO and NiCr_2O_4, the middle layer is Cr_2O_3, and the innermost layer is the SiO_2 inner oxide layer, in which the outermost layer basically peels off. Oxidation of 120h oxidation of the early stages of the third phase, this time, the oxide film peeling serious, Cr20Ni80 alloy wire is about to break.