Microstructure and Friction and Wear Properties of Plasma Surfacing Layer of Ni-based Alloy

The Ni50ANi-based alloy powders were deposited on the surface of 1Cr18Ni9Ti stainless steel by plasma arc surfacing technology, and the microstructure, microhardness and friction and wear properties of the surfacing layer at different welding currents were studied. The results show that the surfacing layer mainly consisted of γ-Ni and precipitates such as CrB, M23(C, B)6, Cr7C3, Cr5B3, Ni3Si and Ni3B. The morphology of surfacing layer varied with the increase of welding current. When the welding current was 160 A, the microstructure was floret-like and granule-like and the surfacing layer had the highest microhardness of 680 HV, and its wear resistance was the best. The wear quantity of the surfacing layer increased with the increase of wear time, and the wear quantity was the largest when the current was 190 A. Wear mechanism of the surfacing layer was mainly adhesive and accompanied by mild abrasive and oxidative wear appearing in later stage