Ni-WB2复合熔覆层的微观组织及摩擦磨损性能

利用真空熔覆技术在45钢表面制备了Ni-WB₂复合熔覆层，利用SEM、EDS、XRD等分析其组织特征，利用销盘式摩擦试验机对其摩擦磨损性能进行了测试与分析。结果表明，Ni-WB₂复合熔覆层组织致密并与基体呈牢固的冶金熔合，熔覆层具有特殊的分层结构，分为网状结构层、过渡结构层和扩散熔合层，网状复合区又分为网状Ⅰ区和网状Ⅱ区。扩散区主要由铁基固溶体和镍基固溶体构成，过渡区的主要组成相为γ-Ni及Cr的碳化物，网状复合区的主要组成相有镍基合金、铬碳化物、WB₂、镍硅共晶以及WB₂与镍基合金中的元素形成的复杂硼化物和碳化物。当WB₂含量低于20%时，随着WB₂在复合熔覆层中含量的增加，其磨损率及摩擦因数均逐渐降低，当WB₂含量为15%时，Ni-WB₂复合熔覆层的磨损率及摩擦因数与基体相比，分别降低了48.94%与14.62%。网状分布的硬质相在摩擦过程中起到支撑载荷的作用，摩擦磨损过程中形成了WO_x...

Microstructure and wear performance of Ni-WB2 composite clad layer

Ni-WB₂ composite clad layer was prepared on the 45 steel substrate through vacuum cladding technology. The microstructure of the clad layer was characterized by means of SEM, EDS and XRD, and wear performance was studied by using pin-disc type wear apparatus. The results show that the Ni-WB₂ composite clad layer is dense, and a strong metallurgical bond formed at the interface between the clad layer and the substrate. The clad layer can be subdivided into reticular zone, transition zone and diffusion zone based on its microstructure, and the reticular composite zone is divided into area Ⅰ and area Ⅱ. The diffusion zone is mainly composed of Fe-based solid solution and Ni-based solid solution. The main phases of the transition zone are γ-Ni and chromium carbide, and the main compositions of the reticular composite zone are Ni-based alloy, chromium carbide, WB₂, nickel silicon eutectic and complex comppund formed owing to the chemical combination between the WB₂ and elements of nickel-based alloy. When the WB₂ content is lower than 20%, both the wear rate and friction factor of the Ni-WB₂ composite clad layer decrease gradually with the increase of WB₂ content. When the WB₂ content is 15%, the wear rate and friction factor of Ni-WB₂ composite clad layer decrease by 48.94% and 14.62% respectively compared with that of the 45 steel substrate. During the wear process, the load supporting effect of the hard phase with network distribution and the formation of WO_x oxide are conducive to reduce the friction and wear of the Ni-WB₂ composite clad layer.