感应重熔对NiCrBSi/WC-Ni复合涂层组织和力学性能的影响

Effect of induction remelting on microstructure and mechanical properties of NiCrBSi/WC-Ni composite coatings

采用大气等离子喷涂制备了NiCrBSi/WC-Ni复合涂层,并采用高频感应加热的方法对涂层进行了重熔处理。与NiCrBSi涂层进行对比,分析了涂层截面的显微组织及涂层与基体界面的结合状况,对重熔前后的两种涂层进行了划痕测试,并对大气等离子喷涂制备的两种涂层在不同载荷进行了耐磨性测试。结果表明,感应重熔使得涂层由机械结合变为冶金结合,增强了涂层的内聚力;感应重熔后,NiCrBSi/WC-Ni复合涂层的附着力大幅度提高,涂层的孔隙率和显微硬度降低。NiCrBSi/WC-Ni复合涂层的显微硬度和耐磨性远高于NiCrBSi合金涂层。WC-Ni的添加没有对涂层的摩擦系数产生明显的影响。

NiCrBSi alloy coatings and NiCrBSi/WC-Ni composite coatings were prepared by air plasma spraying and remelted by high frequency induction heating. Cross sectional microstructure and substrate/coating bonding of these two coatings were compared. Scratch test was carried out for both as-sprayed and remelted coatings,and wear resistance of two different coatings prepared by atmospheric plasma spraying was tested under different loads. The results show that induction remelting makes coatings from mechanical bonding into metallurgical bonding. The remelting process remarkably increases both the cohesion and adhesion strength of the coatings. The coatings present lower porosity and micro-hardness after being remelted. WC-Ni added in coating significantly improves not only micro-hardness but also wear resistance. Moreover,the friction coefficient of the coating is found independent on WC-Ni incorporation and applied loads.