Microstructures and performances of Ni-SiC coatings manufactured by laser cladding deposition

Abstract

45# steel substrates were coated with Ni-SiC by using the laser cladding deposition (LCD) method in this article. X-ray diffractometer (XRD), scanning electron microscope (SEM), micro-hardness meter, wear/friction tester and electrochemical workstation were used to examine the surface morphology, microhardness, wear and corrosion performances, and phase structure of the Ni-SiC coatings. The results indicated that the structures of Ni-10SiC and Ni-30SiC coatings were columnar dendrites and equiaxed crystals (finer in Ni-30SiC coating). The Ni-10SiC and Ni-30SiC coatings were passed through initial and stable wear stages. The average micro-hardness values of Ni-30SiC and Ni-10SiC coatings were separately about 851.3 HV and 748.4 HV. Results showed that the Ni-10SiC and Ni-30SiC coatings suffered stable and initial wear phases. Several big grooves and spalling pits were noted on the sported surface of the Ni coating. While shallow scratches were observed on the wear surface of Ni-30SiC coating. In addition, the Ni-30SiC coating had the lowest corrosion current density (6.325 ×10−6 A/cm2), demonstrating the most efficient corrosion resistance among all three coatings.