【摘要】 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。更多还原

【Abstract】 In order to improve wear resistance of parts,a Ni-Cr-B-Si alloy coating was prepared on 15 CrMo steel surface by pre-placing a Ni-Cr-B-Si alloy powder layer of 0.4 mm in thickness using flame spraying and then melting the layer by micro-beam plasma arc(MBPA).The interface of the coating to substrate,microstructure,composition distribution,micro-hardness,wear and corrosion resistance of the Ni-Cr-B-Si cladding layer and substrate were examined.The results show that the Ni-Cr-B-Si cladding layer is compact with a good metallurgical bonding to substrate.Under optimizing process parameters,a large number of equiaxed grains are observed on the surface of the cladding layer.The micro-hardness from substrate to cladding layer exhibits step distribution.As compared with the base metal,the micro-hardness of cladding layer increases obviously by about 3 times.The electrochemical test results show that the corrosion resistance of the Ni-Cr-B-Si alloy cladding layer in 3.5% NaCl solution is significantly higher than that of the base metal.更多还原