论文部分内容阅读
采用火焰喷涂的方法在15CrMo钢表面预置一层约0.4 mm厚的Ni-Cr-B-Si合金层,然后利用微束等离子弧作为热源进行重熔。通过试验深入分析了熔覆层与基材的结合界面、显微组织及成分分布情况,测试了熔覆层的显微硬度、耐磨性及抗腐蚀性等,并与基材进行了对比。结果表明,通过火焰喷涂+微束等离子弧重熔方法相结合制备的Ni-Cr-B-Si熔覆层,组织致密,界面清晰,成分过渡平缓,与基体达到良好的冶金结合;在优化工艺参数下熔覆层表面形成大量的等轴晶;由基材到熔覆层显微硬度呈阶梯分布,与基材220 HV0.025相比,熔覆层显微硬度提高到500～750 HV0.025,耐磨性也得到显著提高;电化学试验结果表明,在3.5%的NaCl腐蚀溶液中经微束等离子弧熔覆的镍基合金涂层的耐蚀性明显高于基材。
A layer of about 0.4 mm thick Ni-Cr-B-Si alloy was precoated on the surface of 15CrMo steel by flame spraying, and then remelted by using micro-plasma arc as a heat source. The bonding interface, microstructure and composition distribution of the cladding layer and the substrate were analyzed through experiments. The microhardness, wear resistance and corrosion resistance of the cladding layer were tested and compared with the substrate. The results show that the Ni-Cr-B-Si cladding layer prepared by flame spraying + micro-arc plasma arc remelting has the advantages of compact structure, clear interface, gentle transition of composition and good metallurgical bonding with the substrate. In the optimized process A large number of equiaxed grains were formed on the surface of the cladding layer. The microhardness of the cladding layer increased from step to step. Compared with 220 HV0.025, the microhardness of the cladding layer increased to 500 ~ 750 HV0. 025, wear resistance has also been significantly improved; electrochemical test results show that 3.5% NaCl solution by micro-plasma arc cladding nickel-based alloy coating corrosion resistance was significantly higher than the substrate.