MICROSTRUCTURE PERFORMANCE AND SYNTHESIS OF THE ARGON-ARC CLAD COBALT BASE COMPOSITE COATING

Abstract

Composite coating was obtained by argon-arc clad (AAC) of the Stellite20-Si3N4 pre-placed mixed powders on a TA7 titanium alloy substrate, which increased the micro-hardness of the substrate surface significantly; then this produced coating was re-melted by an argon arc, forming a hard layer on the coating surface. The AAC and re-melted coatings were investigated using a scanning electron microscope and high-resolution transmission electron microscope, indicating that amorphous and nanocrystalline phases were produced in the coating surface after an argon-arc re-melting process, which increased the wear resistance of such coatings significantly.