等离子喷涂制备Mo-Si-B复合涂层的高温抗氧化行为研究

STUDY ON HIGH-TEMPERATURE OXIDATION RESISTANCE OF Mo-Si-B COMPOSITE COATING PREPARED BY PLASMA SPRAYING

本文采用等离子喷涂法在钼电极表面制备了Mo-Si-B复合涂层,利用SEM观察涂层的显微形貌,通过XRD分析涂层的物相组成,通过DSC-TGA考察了涂层钼电极在空气环境中的抗氧化行为。结果表明:当Mo∶B∶Si添加比例达3∶1∶1时,钼电极的涂层由MoSi_2相和MoB相组成,涂层的内部致密,与基体钼电极结合紧密;在抗氧化过程中,涂层经历了氧化增重、平稳运行、再次增重3个阶段;涂层物相最终转化为MoSi_2相、Mo_5Si_3相、B_2O_3相和Si O2相。

Mo-Si-B composite coating was prepared on the surface of molybdenum electrode by plasma spraying. The microstructures and phase composition of the coatings were measured by SEM and XRD. The oxidation resistance in air was measured by DSC-TGA. The results show thatwhen the ratio of Mo＊ B＊ Si was 3： 1： 1 ,the molybdenum elec-trode coating comprised of MoSi2and MoB phases which shows higher density and closer interfacial bonding with matrix molybdenum electrode. The oxidization of coating experienced three stages ： the first stage was in the state of oxidative weight gain, the second stage was in steady operation and the third stage was slow weight gain. The molyb-denum electrode coating comprised of MoSi2 , B203Mo5Si3and Si02 phases after oxidation at 1 450℃ in air.