MICROSTRUCTURE AND HIGH-TEMPERATURE WEAR BEHAVIOR OF FE-BASED AMORPHOUS COATINGS BY LASER CLADDING

Abstract

FeCrMoCB amorphous coatings were prepared on 316 stainless steel via an amorphous powder. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to analyze the microstructure, composition, and phase structure of the coatings. Hardness and friction wear testers were applied to investigate the microhardness and wear behavior of the coatings. Results show that the Cr23C6, Cr15Fe7C6 and Fe3Mo crystal phases appeared after laser cladding relative to the complete amorphous powder, and the amorphous phase fraction of the coating was calculated up to 68.4 % using the Verdon method. The coating exhibited a dominating adhesive wear mechanism under room temperature (RT) and transformed to a fatigue wear mechanism as wear test temperature increased to 600 °C. As the temperature was elevated from RT to 600 °C, the wear rate increased from 26 × 10–6 mm3/N·m to 79 × 10–6 mm3/N·m. The laser-cladded Fe-based amorphous coating exhibited much stronger wear performance than the 316 stainless steel, even the wear rate reached one third of that of steel.