Effects of TiC/CeO_2 addition on microstructure and wear resistance of Ni-based composite coatings fabricated by laser cladding on H13 steel

摘要

Ni-based composite coating added 10%TiC/1%CeO2, 20%TiC/1%CeO2, 20%TiC and 30%TiC/1%CeO2 (wt%) was prepared on the surface of H13 steel by laser cladding. The microstructure, hardness, friction and wear properties of the composite coatings was investigated by XRD, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) and microhardness tester and friction abrasion tester. The result showed that the Ni-based composite coatings were mainly composed of the matrix -(Ni, Fe) solid solution and the reinforcement phases were TiC, Ni2Si, (Cr, Fe)(7)C-3 and Cr23C6. TiC has less distribution at the bottom and more surface distribution in the coating as a hard phase and the microstructure was refined by the TiC/1%CeO2 addition. The hardness of the composite coating was improved by the TiC/1%CeO2 addition and the highest hardness was obtained when the TiC content was 30%. The composite coating has obviously more high wear resistance than the Ni60 coating, and the composite coating with 20% TiC/1%CeO2 addition acquired super wear resistance. The wear mechanism is mainly abrasive wear and some fatigue wear for the Ni60 coating, but turns to fatigue wear and brittle spalling for the composite coating, especially with high TiC content.