高能脉冲类激光熔覆镍基合金层的组织及性能

为了提高304不锈钢表面的综合性能,采用高能脉冲类激光熔覆沉积技术在304不锈钢表面制备了镍基合金熔覆层.采用扫描电子显微镜、能谱仪、X射线衍射仪、销-盘磨损试验机与电化学测试系统对镍基合金熔覆层的显微组织、相结构、耐磨损性能和电化学腐蚀性能进行了研究.结果表明,镍基合金熔覆层与304不锈钢基材呈良好的冶金结合,熔覆层的相对耐磨损性为304不锈钢基材的4.4倍.熔覆层组织由γ-Ni基体相、Ni_3Mo、Fe_7Mo_3和Cr_(23)C_6碟状增强相与不规则棒状增强相组成.增强相是提高耐磨损性能的主要原因,增强相与基体相的电极电位差是导致腐蚀电流密度增加的主要原因.

Microstructures and properties of Ni-based alloy cladding coating by high-energy pulsed like-laser

In order to improve the comprehensive surface properties of 304 stainless steel, the Ni-based alloy cladding coating was prepared on the surface of 304 stainless steel with the high-energy pulsed like-laser deposition technology. The microstructure, phase constituent, wear resistance and electrochemical corrosion performance of Ni-based alloy cladding coating were studied with scanning electron microscope(SEM), energy dispersive spectroscope(EDS), X ray diffractometer(XRD), pin-disk wear tester and electrochemical test system. The results show that the Ni-based alloy cladding coating has good metallurgical bonding to 304 stainless steel, and the relative wear resistance of Ni-based alloy cladding coating is 4.4 times high as that of 304 stainless steel. The microstructure of Ni-based cladding coating is composed of γ-Ni matrix phase, Ni₃Mo, Fe₇Mo₃ and Cr₂₃C₆ butterfly-like hard reinforcing phases and irregular rod-like hard reinforcing phase. The hard reinforcing phases are the key reason for improving the wear resistance. The electrode potential difference between the hard reinforcing phases and matrix phase is the main reason for the increase of corrosion current density.