高速电弧喷涂FeNiCrAl/Cr_3C_2涂层的高温氧化性能和氧化机理

High temperature oxidation resistance and oxidation mechanism of FeNiCrAl/Cr_3C_2 composite coating deposited by high velocity arc spraying

选用两种不同外皮的Fe Ni Cr Al/Cr3C2金属陶瓷粉芯丝材,采用高速电弧喷涂技术在45钢基体上制备涂层.采用增重法研究Fe Ni Cr Al/Cr3C2涂层在750℃时的氧化动力学曲线,利用金相显微镜、扫描电镜、X射线衍射仪研究涂层的显微组织结构和氧化产物,分析涂层在750℃时的抗高温氧化性能和氧化机理.结果表明,Fe NiCr Al/Cr3C2涂层的氧化动力学曲线呈抛物线型,涂层的增重明显低于20G钢,并且以304不锈钢为外皮的涂层的抗高温氧化性能明显优于以430不锈钢为外皮的涂层;涂层氧化后表面生成致密的氧化膜,阻塞氧的扩散通道,抑制氧化,起到保护作用.

FeN iC rA l / Cr3C2metal-ceramic composite coating was prepared on the 45 steel by high velocity arc spraying process. The oxidation kinetic curves of the coating was measured at 750 ℃ for 200 h. Optical microscopy,scanning electron microscopy,and X-ray diffraction were used to analyze the microstructures and the oxidation products of the coating. The high temperature oxidation mechanism was discussed. The results show that the oxidation kinetic curves of the coatings followed a parabolic law. The weight gain of the FeN iC rA l / Cr3C2 coating is much lower than that of the 20 G steel. The high Ni content FeN iC rA l / Cr3C2 coating shows much better oxidation resistance than that of the other. The oxidation products can block the oxygen diffusion channel to protect the coating.