Laser cladding Co-based alloy/SiCp composite coatings on IF steel

Hardfacing coatings, made of Co-Cr-W-Ni-Si alloy+ 20% SiCp, deposited by laser cladding on IF steel is introduced. Cross-section of such coatings has been examined to reveal their microstructure using optical microscope, scanning electron microscope (SEM) and X-ray diffractometer (XRD). MM-200 type wear tester is used to examine wear resistance of the coatings. The results showed that SiCp is dissolved completely during laser cladding process under this conditions, the primary phase gamma-Co dendrite and Si2W, CoWSi, Cr3Si, COSi2 formed by C, Si reacting with other elements existed in the coatings. There existed some crystallization morphologies in different regions, such as planar (at the interface), followed cellular and dendrite crystallization from interface to the surface. The direction of solidification changes from one direction perpendicular to interface to multi-directions at the central and Upper regions of the clad. The results also showed that the wear resistance of the clad improved by adding SiCp. (C) 2003 Elsevier Ltd. All rights reserved.