In-situ Synthesis of MoSi{sub}2/SiC Composite Coating by Laser Cladding

摘要

In order to improve resistance to high temperature and wear resistance of pure aluminum, the laser cladding experiments were conducted on a 3kW continuous wave CO{sub}2 laser to produce in-situ synthesized MoSi{sub}2/SiC composite coatings on pure aluminum. The laser consolidified microstructure and phase evolution were investigated using scanning electron micrograph and x-ray diffraction. The in-situ formation of MoSi{sub}2 /SiC was conducted by adding a mixture of Mo, Si and C precursor powder layer followed by melting the layer and substrate under a laser beam. The experimental results showed that these compound, MoSi{sub}2 and SiC can be formed from three distinct powders of Mo, Si and C on Al alloy, provided that supplied energy was sufficient to start the reaction between the initial products, a good metallurgical bond between coating and the substrate can be achieved. The microstructures of the coating were composed of MoSi{sub}2, Mo{sub}5Si{sub}3 and SiC phases. The microhardness of coating was about twelve times that of the aluminum substrate, the maximum value reached HV{sub}0.2 1200.