Performance and Property of Ni Base Coatings by Using Plasma Arc Technology for 18Cr2Ni4WA Steel Repairing

To understand the structure and performance of Ni base coatings on 18Cr2Ni4WA steel, the key techniques of plasma arc cladding method are introduced. Microstructure and microhardness of the coating clad were analyzed by using Vickers hardness tester,scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).Results show that the phase of the coating is composed of γ-Ni solid solution， nickel boride Ni3B，carbide Cr27C6 and Cr2B3 type chromium boride. The coating has no cracks and does not exhibit porosity, the bonding between layers is compact and the boundaries are not observed. The coating is featured by a homogenized microstructure; small grain and no evident heat-affected zone.