Cr20Ni80电热合金在高温空气条件下氧化机制研究

Studyon oxidation mechanism of Cr20Ni80 electrothermal alloyunder high temperature air condition

通过高电阻电热合金快速寿命仪氧化装置研究了Cr20Ni80电热合金在空气中极限温度1200℃下的高温抗氧化性,并采用扫描电镜(SEM)和能谱分析(EDS)研究了氧化膜的表面形貌,氧化膜的厚度及成分,并通过热力学计算研究了氧化膜的形成过程。结果表明,在1200℃氧化60h形成了3层氧化膜。最外层为NiO和NiCr2O4,中间比较致密均匀的Cr2O3,最内层为疏松多孔的SiO2,当氧化时间达到100h时,外层的氧化膜发生剥落。

The high temperature oxidation property of Cr20Ni80 electrothermal alloy was studied by a high resistance heating apparatus at 1200℃heated for 200 hin air.The surface morphology,thickness and composition of the oxide film were observed and analyzed by SEM and EDS.The formation process of oxide film was also discussed by thermodynamic calculation.The results show that three layers of oxide film were formed at 60 hafter oxidation The outer layer is NiO and NiCr2O4,then dense and uniform Cr2O3 followed,and the inner layer is loosely porous SiO2.When the oxidation time is up to 100 h,the oxide film in the outer layer will spalling off.