La_2O_3对Ni基合金激光熔覆层组织和耐磨性的影响

Effect of La 2O 3 on the microstructure and wear resistance of laser clad nickel based alloy coatings

在Ｎｉ基自熔合金粉末中添加不同量的Ｌａ２Ｏ３，并利用激光形成熔覆层。利用扫描电镜、Ｘ射线能谱仪、Ｘ射线衍射仪、显微硬度计和环块摩擦磨损实验机等对激光熔覆层显微组织、化学成分、相结构、显微硬度和摩擦磨损性能进行了研究。结果表明，在激光熔覆层中添加Ｌａ２Ｏ３能细化和净化显微组织；降低基材对熔覆层的稀释率；减小固溶体的晶格常数；提高熔覆层的显微硬度；降低熔覆层摩擦系数并提高其耐磨性能。该文还探讨了Ｌａ２Ｏ３作用的机理。

The nickel based alloy powders with different contents of La 2O 3 addition were laser cladded onto steel substrates. The clad coatings were examined and tested for microstructural features, chemical compositions, phase structure, microhardness, friction and wear properties by scanning electron microscopy (SEM) with X ray energy dispersive analysis (EDX), X ray diffractometer, microhardness tester, block on ring friction and wear tester separately. The results were compared with those of the coatings without La 2O 3 addition. The comparison indicates that the addition of La 2O 3 can refine and purify the microstructure of the clad coating, reduce the dilution of clad material from substrate, decrease the lattice constant of solid solution. Moreover, the friction coefficient of the clad coating with La 2O 3 addition is reduced and the wear resistance of clad coating with La 2O 3 addition is enhanced. The mechanisms of these effects are also discussed in the paper.