A precise cladding with direct diode laser for thin cladding layer

Surface modification technologies such as electro-plating, thermal spraying and laser cladding are commonly used to improve functions of low functional materials’ surfaces. Among them, laser cladding method is a good coating tool for surface modification of materials used in many industrial fields, since they have low heat affection on substrate. Recently, a thin cladding layer is required for alternative of electro-plating, because it will be prohibited by RoHS (Restriction of Hazardous Substances). Although laser cladding method is expected to alternative of this method, it is difficult to make a thin layer without melting of substrate. In order to overcome this drawback, we develop laser cladding with a low power direct diode laser and a small size particle. A coating layer of 150µm±50µm thickness with Vickers hardness of HV500 was obtained using a diode laser of 200W power and SFA powder of 20-35µm. In this study, effect of laser characteristics was examined on the laser cladding layer of carbon steel and stainless steel. After laser cladding, the microstructure of the self-fused alloy layer was analysed with an optical microscope and EPMA. The mechanical properties of self-fused alloy layer are evaluated using Vickers hardness tester and sand erosion tester.