Microstructures and properties of Co-based alloy coatings prepared on surface of H13 steel

The Co-based alloy coatings had been prepared by laser cladding and vacuum fusion sintering. Microstructures of the coatings were investigated and the performance of thermal cycling was also tested using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the coatings and substrates combine well. The main phase compositions of laser cladding coating are γ-Co, Cr23C6 and Ni2.9Cr0.7Fe0.36, while vacuum fusion sintering coating consists of Co, Cr7C3 , and Ni2.9Cr0.7Fe0.36. After thermal cycling, the minimum hot cracking width of laser cladding coating is 14 μm; moreover, laser cladding coating maintains high hardness and hot-cracking susceptibility. Those are beneficial to high temperature wear resistance of hot work dies.