Research on the Preparation Process and Performance of a Wear-Resistant and Corrosion-Resistant Coating

Abstract

In order to study the wear resistance and corrosion resistance of a composite material with a Fe316L substrate and Co-Cr-WC coating, Co-Cr alloy coatings with different mass fractions of WC (hard tungsten carbide) were prepared on a Fe316L substrate by laser cladding technology. The phase composition, microstructure and element distribution were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The hardness of the samples was tested by a Vickers microhardness tester, the friction coefficient and wear amount of the samples were tested by a friction and wear tester, and the corrosion resistance of the samples was tested by an electrochemical corrosion workstation. The results showed that the macroscopic appearance of the coating surface was good without obvious cracks, and the microstructures were mostly equiaxed crystals, cellular crystals and dendrites. With the addition of WC, the structures near the particles became more refined and extended from the surface of the WC particles. When the WC content was 40%, defects such as fine cracks appeared in the coating. The average microhardness of the 30%WC-Co-Cr coating was 732.6 HV, which was 2.29 times that of the Fe316L matrix; the friction coefficient was 0.16, and the wear amount was 14.64 × 10−6 mm3 N−1 m−1, which were 42.1% and 44.47% of the matrix, respectively; the self-corrosion voltage of the cladding layer was 120 mV, and the self-corrosion current was 7.263 × 10−4 A/cm2, which were 30.3% and 7.62% of the substrate, respectively. The experimental results showed that the laser cladding Co-Cr-WC composite cladding layer could significantly improve the wear resistance and corrosion resistance of the Fe316L matrix under the optimal laser process parameters.