利用电火花沉积技术,采用自制电极在P20钢基材表面沉积Ni-Cr合金涂层,研究了沉积层的组织特征、显微硬度分布及耐磨、耐蚀性能.结果表明:通过优化沉积工艺参数可以获得厚度高达430μm的沉积层.电火花沉积层与基体的结合界面属于非均匀混合互熔结晶型界面,沉积层与基体呈现良好的冶金结合;涂层中下部组织为细小的枝晶组织,而上部组织为纳米晶结构.沉积层的硬度呈梯度分布,涂层外层硬度值最高.涂层的耐磨、耐蚀性能比基体有较大提高,涂层上部超细的纳米晶结构是其耐磨性能及耐蚀性能提高的主要因素.%The Ni-Cr alloyed coating was produced on the surface of P20 steel plate with self-made electrode by electro-spark deposition (ESD) technique. The microstructures and properties of the coating were investigated. The results show that ESD process can produce big-thickness coating with proper process parameters, and the thickness is about 430μm. The coating is well bonded to the matrix and the interface between the coating and the substrate is presented as non-uniformly mixed mu-tuai melting crystallization. The superfine dendritic structure prevails in the middle and bottom of the coating and nano-structured grains in the upper coating. The hardness of the coating shows gradient distribution from the surface reached the largest to the substrate reduced sequentially. Nano-structured particles of the upper coating are the main factors leading to high hardness as well as corrosion and wear resistance of the coating.
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