Effects of heat treatment on microstructure and properties of Fe-based amorphous composite coatings

It is found that heat treatment can improve the microstructure and properties of the coating. In this paper, the Fe-Cr-Mo-B-C amorphous composite coatings fabricated by laser cladding technology were heat treated at different temperatures. The effects of heat treatment temperature on the crystallisation, porosity, microhardness, and corrosion resistance of coatings were investigated. The experimental results show that the amorphous content and porosity after heat treatment, the comprehensive properties are improved, and the coating defects are solved. Both the amorphous content and the porosity affect the corrosion resistance of the coatings. The smaller the porosity, the higher the amorphous content, and the stronger the corrosion resistance of the coating. When the difference in amorphous content is small, the porosity of the coating becomes the dominant factor affecting the corrosion resistance of the coating. The experimental results shows that the best optimum heat treatment temperature for the coatings is 200°C.