A comparative study of laser cladding high temperature wear-resistant composite coating with the addition of self-lubricating WS_2 and WS_2/(Ni-P) encapsulation

摘要

In order to inhibit its decomposition and improve its compatibility with the metal matrix during laser cladding, WS_2 powder was encapsulated with a layer of micro Ni-P by electroless plating. The microstructure and tribological properties of the NiCr-Cr_3C_2/30%WS_2 and NiCr-Cr_3C_2/30%WS_2(Ni-P) high temperature self-lubricating wear-resistant composite coatings at RT (room temperature), 300℃ and 600℃ were investigated, respectively. It was found that the NiCr-Cr_3C_2/30%WS_2(Ni-P) coating had a microstructure consisting of primary Cr_7C_3 dendrite, γ-(Fe,Ni)/Cr_7C_3 eutectic and solid lubricant particles WS_2 and CrS, Ni-P electroless plating had decreased the decomposition of WS_2 to some extent, the WS_2 solid lubricant particles dispersed in the ductile γ-(Fe,Ni)/Cr_7C_3 matrix. Friction and wear experiments indicated that the tribological properties of the NiCr-Cr_3C_2/30%WS_2(Ni-P) coating was better than that of NiCr-Cr_3C_2/30%WS_2 coating, the NiCr-Cr_3C_2/30%WS_2(Ni-P) coating presents lower friction coefficient at RT and 300℃ and lower wear rate from RT to the elevated temperature of 600℃.