Effect of induction remelting on microstructure and wear resistance of plasma sprayed NiCrBSiNb coatings

NiCrBSiNb coating was fabricated on AISI 1045 steel ring by plasma spraying and induction heating method. Then the microstructure, mechanical properties and wear resistance of the coating were studied. Results showed that the defects in the as-sprayed coating were almost eliminated and metallurgical bonding was produced between the coating and substrate. Particularly, a diffusion belt of 50 pm in thickness formed in the remelted coating adjacent to the interface after remelting. In addition to Cr23C6, Fe3C and Ni3Si, NbC in-situ precipitated, which had good coherent bonding with the matrix. After remelting, the mechanical properties were improved. Moreover, the wear resistance of the coating was improved dramatically: wear volume decreased by 58%, and the wear modes changed from fatigue wear and abrasive wear to oxidation wear and micro abrasive wear. Hence, the microstructure and wear resistance of plasma sprayed coatings can be significantly and efficiently improved by induction remelting technology.