Interface Behavior and Mechanical Properties of Ni/WC Brazing Coating

Ni/WC composite coating with high wear resistance, corrosion resistance and high hardness characteristics is widely used in shield components, aerospace and other fields. In order to improve the service life of hydraulic machinery overflow components, the Ni/WC composite brazing coating was prepared on the surface of 201 stainless steel by vacuum brazing process with WC particles and Ni-based powder brazing filler metals as raw materials. The interface microstructure and mechanical behavior of the brazing coating were investigated through scanning electron microscope, metallographic microscope and Rockwell hardness tester. The results show that the diffusion behavior of elements between the coating and substrate is mainly the dissolution of Fe, Cr and Mn elements from the stainless steel into the coating microstructure, and the segregation precipitation phenomenon appears on the interface. 25wt% WC coating shows a uniform hardness distribution, whose hardness is 4.6 times higher than that of steel substrate. The wear resistance of coating is increased with increasing the WC content. 15wt%-35wt% WC addition can significantly improve the wear resistance of the steel surface. The wear resistance of the coating is 8.4-15.7 times as high as that of the steel, the surface of the coating does not change significantly, and the crack opening is flat and brittle fracture.