【摘要】 采用热喷涂预置和激光熔覆方法在Q2 35钢基体上熔覆Ni基合金涂层和Ni/WC复合涂层 ,研究激光功率对涂层微观结构的影响。结果表明 ,选择合适的激光输出功率 ,可获得组织分布均匀、低稀释率、与基体结合良好的合金涂层 ;在Ni/WC复合涂层中 ,合理的激光功率使WC颗粒部分熔化 ,并在颗粒周围重新凝固并析出针状碳化物 ,这既有利于提高涂层的硬度又能使未熔化的WC颗粒与涂层内合金溶剂牢固结合。激光功率较大时涂层内WC颗粒烧损并沉底 ,沉积在涂层底部的WC颗粒 ,使基体到涂层的性能发生突变 ,这样既容易引发裂纹及疲劳破坏 ,又不利于涂层表面的耐磨。更多还原

【Abstract】 Ni based alloy coatings and Ni/WC composite coatings were prepared on Q235 steel by thermal spray and larser cladding.The influences of the laser power on the properties of coatings were widely studied.The results showed that the high quality coatings with uniform WC particles distribution,low dilution and good combination with the substrate can be obtained under the optimized laser power.In the Ni/WC composite coatings,WC particles partly dissociated at the edge,and many needle like dendrites grew epitaxially from the surface of the partially melted WC particles under the proper laser power.This can improve the microhardness of the coating and significantly combined the WC particles with the matrix alloy.When the laser power is too large,WC particles at the top of the coating were burned and remained WC particlels sank to the bottom of coating.Acoordingly,there is a sharp transition in hardness at the interface between the coating and the substrate.It easily brings about cracks and fatigue failure,and does not help to improve the wear resistance of the coating.更多还原