Microstructure and Wear Resistance of ZrC-ZrB 2 /Ni Composite Coatings Prepared by Plasma Transferred Arc Cladding

摘要

The ZrC-ZrB 2 /Ni metal matrix composite coatings were in-situ synthesized from a mixture of Ni, Zr and B 4 C by plasma transferred arc (PTA) cladding process. Microstructures and phase constituents of the coatings were characterized by electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD). Microhardness and wear resistance of the coatings were systematically investigated by means of vickers hardness tester and wear tester. The results showed that the main phases of the composite coatings were ZrB 2 and ZrC. The coatings had a sound metallurgical bonding to the SA-283C steel substrate. Microhardness and wear resistance of the substrate were greatly improved by the composite coatings, and both of them showed a tendency to increase first and then decrease with the increase of the Ni content. As the content of Ni was 30 wt.%, the hardness of the coating reached the maximum value, 1522 HV, and the wear resistance was about 15 times that of the substrate.