Microstructure and mechanical properties of Co-based alloy coatings fabricated by laser cladding and plasma arc spray welding

The presented paper concerned a comparison of microstructural characters and mechanical performances between the cobalt based alloy (Co-based) coatings of the same chemical composition and yet fabricated by laser cladding and plasma arc spray welding (PASW), respectively. The phase constituent and microstructure of the coatings was characterized by optical metallography, scanning electron microscopy (SEM), X-ray diffraction spectrum (XRD), transmission electron microscopy (TEM) and energy dispersive spectrum (EDS), while the mechanical properties of the coatings obtained by different procedures were comparatively evaluated according to the microhardness and high-temperature wear resistance tests. As the novelties of the presented research, it was interesting that the amorphous Co-based coating was directly fabricated by laser cladding rather than by cladding-and-remelting method with commercial self-flux alloy powder for the first time. The formation mechanism of the amorphous phase was explained by experiments and finite element simulation. The advantages of the amorphous coatings in mechanical performances were quantitatively revealed. •We made two coatings which have amorphous structures and crystal structures.•The laser cladding coating was excellent in mechanical than the PASW coating.•The wear mechanism of the laser cladding coating and PASW coating was revealed.•The formation mechanism of the amorphous phase was explained.