Microstructures and Properties of Laser Clad Ni-based Metal-ceramics Layers

Laser clad metal ceramics layers of Ni based B 4C(NB 4C) and Ni based SiC(NSiC) have been obtained on 16Mn steel substrate by means of 5 kW continuous wave CO 2 laser. Microstructure, phases, microhardness and sliding wear characteristics of the layers have been studied. Microhardness and sliding wear characteristics of laser clad Ni based alloy layer (Ni60) was also investigated under the same conditions as a contrast. The results show that the microstructure of laser clad layers consists of dendritic solid solution and the fine eutectic structure between the dendrites. NB 4C clad layer mainly consists of γ Ni,γ (Ni,Fe), (Cr,Fe) 7C 3, CrB, Ni 3B, Fe 2B, Fe 23 (C,B) 6 and B 4C. NSiC clad layer mainly consists of γ Ni,γ (Fe,Ni), (Cr,Fe) 7C 3, Cr 23 C 6 and (Cr,Si) 3Ni 3Si. Microhardness and sliding wear resistance of the three laser clad layers have an order from high to low: NB 4C→NSiC→Ni60.