Microstructure and Friction and Wear Properties of Plasma Niobium Surface Alloying Layer on 0Cr18Ni9 Steel

A uniform and compact niobium alloying layer with the thickness of 22 μm was prepared on the 0Cr18Ni9 austenitic stainless steel surface using double-glow plasma surface alloying technology.The composition,microstructure and tribological properties of the alloying layer were examined.The results show that the Nb alloying layer was mainly composed of Nb-containing carbides (NbC,Nb6C5) and intermetallic compounds (Cr2Nb,Fe2Nb).The surface hardness of the alloying layer enhanced by one time compared with that of the substrate,which reached 614 HV0.025.The friction coefficient of the Nb alloying layer (8.05×10-2) and the substrate (7.97×10-2) were roughly same.The main wear mode of both the substrate and alloying layer was a mixture of adhesion and abrasion.The wear rate of the alloying layer decreased obviously compared with that of the substrate.