Microstructure and wear resistance of Fe-Cr-Mo-Co-C-B amorphous composite coatings synthesized by laser cladding

Abstract

A novel amorphous composite coating was synthesized successfully on 3Cr13 stainless steel by laser cladding Fe-Cr-Mo-Co-C-B amorphous alloy 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 used to analyze the hardness and wear resistance of the coatings. Results show that the cladding layer has an amorphous/crystalline composite structure, which is composed of a columnar grain region at the bottom and an amorphous region in the upper layer. The solute redistribution between the coating and the substrate in the bonding zone and the lower cooling rate at bottom account for the occurrence of crystallization. The highest hardness of the cladding layer is 1179 HV0.5, which is about 6 times that of the 3Cr13 stainless steel substrate (200 HV0.5). The cladding layer greatly improves the wear resistance of the substrate with a much lower coefficient of friction and wear mass loss compared with the substrate.