激光熔覆TiB2颗粒增强镍基合金复合涂层的微观组织与摩擦学性能研究

为了提高铝合金摩擦构件的耐磨性能，运用激光熔覆技术在铝合金表面制备了TiB₂颗粒增强镍基合金（TiB₂/镍基合金）复合涂层，分析了其微观组织结构，研究了其在干摩擦和海水介质中的摩擦磨损行为与机制。结果表明：复合涂层中均匀分布有TiB₂增强相，并含有TiB、TiC、CrB和Cr₂₃C₆等反应生成硬质相，显微硬度达到855.8HV_0.5，是铝合金母材的6.7倍；不同环境介质中，复合涂层的摩擦系数和磨损失重均较镍基合金涂层和铝合金母材显著降低；干摩擦条件下，复合涂层的磨损机理以微观切削磨损为主，并伴有一定的硬质颗粒剥落；海水环境中，复合涂层的磨损机理转变为微观切削磨损和点蚀腐蚀磨损。

Microstructure and Tribological Properties of Laser Cladding TiB2/Ni-based Alloy Composite Coatings

In order to improve the wear resistance of aluminum alloy frictional parts, TiB₂ particles reinforced Ni-based alloy composite coatings are prepared by laser cladding technology. The microstructure of the composite coatings is studied. The tribological properties of the composite coatings in dry friction and seawater environment are investigated. The results show that the TiB2 reinforced phase is uniformly distributed in composite coating, and contains the reactively generated hard phases of TiB, TiC, CrB and Cr₂₃C₆ , etc. Its microhardness is 855.8HV_0.5, which is 6.7 times as high as that of the aluminum alloys. In different friction conditions, the friction coefficients and wear losses of the composite coatings are significantly lower than those of Ni-based alloy coatings and aluminum alloys. The wear mechanisms of the composite coatings in dry friction are micro-cutting wear accompanied with hard particle peeling. In seawater environment, the composite coatings suffer from micro-cutting wear and pitting corrosion wear.