Effect of WC-Co addition on tribological and cracking behavior of laser cladded Fe-based amorphous/crystalline composite coatings

The effect of doping ceramic reinforcing particles during the fabrication of amorphous alloy coatings by laser cladding technology has rarely been investigated. A crack-free Fe-based amorphous/crystalline composite coating with good tribological properties was prepared on the surface of 40Cr steel by changing the content of WC-14Co addition during laser cladding. As the content of WC-14Co particles increases, cracks in the coating are first suppressed until gradually disappearing and then re-forming, reaching a crack-free state at 5 wt% addition. SEM, TEM and EBSD results showed that the incorporation of WC-14Co successfully introduced fine WC particles into the coating structure and refined the microstructure of the coating. The Vickers hardness of the coating is 937.7 Hv, and the wear loss of the coating was 1.1 x 10(-2) mm(3) at a load of 30 N, a friction counterpart of Al2O3, and a sliding speed of 9 mm/s for 1.5 h. The crack-free and good tribological properties of the coating were mainly attribute to the uniform and diffuse distribution of WC, which inhibits the directional growth of columnar crystals at the coating-substrate interface and promotes the refinement of the crystal structure.