The Microstructure of Ni/ZrO<sub>2</sub> Infiltrated Composite Layer

The Ni/ZrO2 composite powder was used as raw materials to fabricate the surface infiltrated composite layer on cast steel substrate through vacuum infiltrated casting technology. The microstructure indicated that the infiltrated composite layer included surface composite layer, Ni-based alloying layer and diffusion transition layer. The thickness of diffusion transition layer deceased with the increasing thickness of preform. The surface infiltrated composite layer was composed of ZrO2 ceramic particles, Cr2B and NiB intermetalic compounds as well as Ni-based solid solution. The Ni-based solid solution and Fe-based solid solution was the main composition for diffusion transition layer. The change of micro-hardness of surface infiltrated composite layer presents gradient from surface of infiltrated layer to substrate.