利用激光熔覆工艺制备锡基合金熔覆层、镍/锡基合金熔覆层,对两种熔覆层的显微组织、硬度及摩擦磨损性能进行分析,并与铸造锡基巴氏合金进行对比。结果表明:锡基合金熔覆层由方块状SnSb、花瓣状Cu6Sn5和基体相α-Sn组成。由于镍元素的扩散作用,在镍/锡基合金熔覆层底部生成了NixSny和CuNiSb2混合相;两种激光熔覆层在截面深度0.1~0.7 mm处的显微硬度差别不大,均约为50 HV;随着截面深度增大,镍/锡基合金熔覆层的硬度急剧升高,这是因为过渡层中的镍元素扩散到了熔覆层,形成了Sn-Ni金属间化合物,增大了这一区域的硬度;镍/锡基合金熔覆层和锡基合金熔覆层的平均摩擦因数分别为0.165和0.199,均优于铸造锡基巴氏合金;两种激光熔覆层的磨损机理为表面疲劳磨损,磨损面有点蚀现象。铸造锡基巴氏合金的磨损较为严重,出现了犁沟,磨损机理为表面疲劳磨损和磨粒磨损。

A tin-based alloy cladding layer and a nickel/tin (Ni/Sn)-based alloy cladding layer are prepared using a laser cladding process. The microstructure, hardness, and friction and wear properties of the two cladding layers are analyzed and compared to those of the as-cast Sn-based Babbitt alloy. The results reveal that the prepared Sn-based alloy cladding layer comprises square-shaped SnSb, petal-like Cu₆Sn₅, and a matrix phase α-Sn. A mixed phase of Ni_xSn_y and CuNiSb₂ is formed at the bottom of the Ni/Sn-based alloy cladding layer due to Ni diffusion. The two cladding layers have similar microhardness at a cross-sectional depth of 0.1-0.7 mm and both layers have a hardness value of approximately 50 HV. As the depth of the section increases, there is an abrupt increase in the microhardness of the Ni/Sn-based alloy cladding layer because the Ni element in the transition layer diffuses to the cladding layer, forming an Sn-Ni intermetallic compound. The Sn-Ni intermetallic compound increases the microhardness of this region. The average friction coefficients of the Ni/Sn-based cladding layer and Sn-based cladding layer are 0.165 and 0.199, respectively, which are superior to that of the as-cast Sn-based Babbitt alloy. The two cladding layers have better wear and fatigue properties than the as-cast Sn-based Babbitt alloy because the wear mechanism of the former is surface fatigue wear and pitting phenomenon is found on the wear surface. On the other hand, the wear mechanism of the latter is surface fatigue wear and abrasive wear, and the surface is severely worn, which results in furrows.