Bond Behaviors Characterization of the Plasma Sprayed NiCrBSi Coatings by Scratch Testing on Coatings Cross-Section

Three plasma sprayed NiCrBSi coatings were deposited on 1045 steel substrate. The cohesion bond strength of the coatings was characterized by cross-sectional scratch testing. The sliding wear behaviors of the coatings were studied under oil lubrication. Results indicate that the wear volume and the microhardness of plasma sprayed NiCrBSi coatings are not invariably linked. The wear resistance of the coatings ranking from the highest to the lowest is Ni25, Ni35 and Ni45. There existed a good correlation between the wear behavior and the cohesion of NiCrBSi coatings. The wear mechanism of the coatings included abrasive wear and spalling wear. The former was the dominant mechanism at lower load. By increasing load, spalling of splats of coating was dominant wear mechanism.