电热爆炸喷涂NiAl涂层的热循环氧化行为

Thermal Cyclic Oxidation Behavior of NiAI Coating Prepared by Electric Thermal Explosion Spray

电弧喷涂技术具有高速、高温、涂层硬度高、与基体结合良好的优点,可满足现代航空航天业对材料服役温度、密度及性能的要求。采用电热爆炸喷涂法在DZ125高温合金表面制备了NiAl涂层,研究了该涂层在1050℃下的循环氧化行为,并利用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对热循环后的试样进行了分析。结果表明,所制备的NiAl涂层致密、晶粒细小、与基体结合良好;涂层在1050℃热循环后其表面生成了致密的AlO氧化层,能阻止氧向内扩散,减缓内层的氧化速率,从而起到了保护基体的作用。

NiAl coating was prepared on DZ125 superaUoy by electric thermal explosion spray.The ther-mal cyclic oxidation behavior of the coating at 1 050 °C was inves-tigated.The compositions and microstructures of the thermally cy-cled samples were analyzed by means of scanning electron micros-copy(SEM),energy dispersive spectrometry(EDS),and X-ray diffraction(XRD).Results showed that the NiAl coating com-posed of refined grains was dense and well bonded to the sub-strate.After thermal cyclic oxidation at 1 050 °C in air,A12O3 oxide layer was formed on the surface of the substrate,acting to retard the diffusion oi oxygen into the inner zone and inhibiting the oxidation of the inner layer,and hence protecting the sub-strate from oxidation at elevated temperatures.