Microstructure evolution and high temperature corrosion behavior of FeCrBSi coatings prepared by laser cladding

摘要

In this study, an FeCrBSi coating was deposited on a stainless steel substrate by laser cladding with a 6 kW CO2 laser to improve the hardness and corrosion resistance. The phase composition, microstructure evolution and chemical composition of the coating were investigated via X-ray diffraction (XRD), confocal scanning laser microscopy (CSLM), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX). Microhardness and high temperature corrosion tests in molten aluminum were also conducted for evaluating the properties of the coating. The XRD pattern suggested that the coating was particularly composed of martensite, (Fe, Cr)(7)C-3 and CrFeB hard phases. The microstructure results exhibited that equiaxed dendrites, dendrite networks, columnar dendrites, cellular and planar grains were distributed from the surface to the bottom of the coating. The hardness of the substrate increased from 217 H-0.2 to 762 HV0.2. Moreover, the laser cladding FeCrBSi coating exhibited good corrosion resistance in molten aluminum, thereby making it a promising candidate in the surface modification and protection of hot dip aluminum equipment.