Effect of heat treatment on the microstructure and mechanical properties of Fe-based amorphous coatings

Amorphous coatings were fabricated by arc spraying and the effect of the post heat treatment on the microstructure, and the mechanical properties of arc sprayed coatings were studied. Post heat treatment was conducted in the atmospheric environment within the temperature ranged from 500 °C to 800 °C. The microstructure characteristics were analyzed by means of optical microscopy (OM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA), scanning electron microscopy (SEM), differential thermal analysis (DTA) and transmission electron microscopy (TEM). It was found that with the increase of anneal temperature, the microstructure of the sprayed coatings had several changes as follows: the reduction of porosity, the decomposition and the crystallization of amorphous phase, and the formation of precipitates. The microhardness of the sprayed coatings increased after the heat treatment and it can reached to 1275 HV300g at the post treated at 600 °C. All the coatings exhibited an excellent abrasive wear resistance, approximately 6 times higher than that of the arc-sprayed 3Cr13 coating.