Laser cladding nickel-based alloy coating （Ni60） and nickel-based composite coating doped with WC particles by 35 % （WCp/Ni） were produced on the low-carbon steel substrate by CO2 continuous wave laser with power ...Laser cladding nickel-based alloy coating （Ni60） and nickel-based composite coating doped with WC particles by 35 % （WCp/Ni） were produced on the low-carbon steel substrate by CO2 continuous wave laser with power of 5 kW using the injected powder technique. The effect of laser power on microstructure and wear resistance of laser cladding WCp/Ni cermet coating was investigated. The WCp/Ni alloy coating with evenly distributed WC ceramic phases and the better bond with the substrate alloy was obtained at a power of 2.2 kW. Diffusion solution reaction happened between WC particles and the substrate alloy during laser cladding, and led to the formation of block rich-tungsten carbide on the edges of the WC particles, especially at higher power. The WCp/Ni alloy coating consists of the undissolved WC particles, the block or dendritic rich-tungsten carbide, the bar-like rich-chromium carbide, and dendrite solid solution and eutectic structure among the carbides. Microhardness and wear resistance of the WCp/Ni coating at different powers were much higher or better than those of Ni60 alloy coating, and the best results were obtained at power of 2.2 kW.展开更多
The SiCp(20 %)reinforced cobalt-based alloy composite coatings deposited by laser cladding on IF steel were introduced.The microstructure across the whole section of such coatings was examined using optical microscope...The SiCp(20 %)reinforced cobalt-based alloy composite coatings deposited by laser cladding on IF steel were introduced.The microstructure across the whole section of such coatings was examined using optical microscope,scanning electron microscope(SEM)and X-ray diffractometer(XRD),and the wear resistance of the coatings was measured by MM-200 type wear testing machine.The results show that the SiCpis completely dissolved during laser cladding and the primary phase in the coatings isγ-Co.The other phases,such as Si2 W,CoWSi,Cr3 Si and CoSi2,are formed by carbon,silicon reacting with other elements existing in the melting pool.There are various crystallization morphologies in different zones,such as planar crystallization at the interface,followed by 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 wear resistance of the clad is improved by adding SiCp.展开更多
基金Item Sponsored by Research Programof Anhui Science and Technology Office (2005KJ030) and Korea Research FoundationGrant (KRF-2004-005-D00096)
文摘Laser cladding nickel-based alloy coating （Ni60） and nickel-based composite coating doped with WC particles by 35 % （WCp/Ni） were produced on the low-carbon steel substrate by CO2 continuous wave laser with power of 5 kW using the injected powder technique. The effect of laser power on microstructure and wear resistance of laser cladding WCp/Ni cermet coating was investigated. The WCp/Ni alloy coating with evenly distributed WC ceramic phases and the better bond with the substrate alloy was obtained at a power of 2.2 kW. Diffusion solution reaction happened between WC particles and the substrate alloy during laser cladding, and led to the formation of block rich-tungsten carbide on the edges of the WC particles, especially at higher power. The WCp/Ni alloy coating consists of the undissolved WC particles, the block or dendritic rich-tungsten carbide, the bar-like rich-chromium carbide, and dendrite solid solution and eutectic structure among the carbides. Microhardness and wear resistance of the WCp/Ni coating at different powers were much higher or better than those of Ni60 alloy coating, and the best results were obtained at power of 2.2 kW.
基金Item Sponsored by International Government Cooperation Projects of Sino-Korea(2002009)and Sino-America(01088013)
文摘The SiCp(20 %)reinforced cobalt-based alloy composite coatings deposited by laser cladding on IF steel were introduced.The microstructure across the whole section of such coatings was examined using optical microscope,scanning electron microscope(SEM)and X-ray diffractometer(XRD),and the wear resistance of the coatings was measured by MM-200 type wear testing machine.The results show that the SiCpis completely dissolved during laser cladding and the primary phase in the coatings isγ-Co.The other phases,such as Si2 W,CoWSi,Cr3 Si and CoSi2,are formed by carbon,silicon reacting with other elements existing in the melting pool.There are various crystallization morphologies in different zones,such as planar crystallization at the interface,followed by 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 wear resistance of the clad is improved by adding SiCp.
