Preparation and Characterization of Nickel-Based Composites Coatings Reinforced by TiB2+WC on Stainless Steel by Laser Cladding

The preparation and characterization of a nickel-based composite coating reinforced by TiB2 particles produced in situ and WC particles on stainless steel by laser cladding have been investigated. The experiment results show that the coating obtained at suitable parameters epitaxially grows from the substrate. The coating is mainly composed of γ-Ni dendrite and dispersed TiB2 and WC particles. In the upper part of the coating, the white phase dispersed in the coatings is mainly fine batt-shaped TiB2 particles. In the middle and bottom parts of the coating, the white phase is mainly composed of comparatively coarse equiaxial WC particles, only an small amount of fine TiB2 particles are present. The different distribution of TiB2 and WC should be attributed to the density difference of TiB2, WC and Ni-based alloys and the comparatively slow scanning rate. No cracks were observed throughout the whole coating, especially in the interface, after the coating was deal with by the thermal shock experiment, which shows that the coating processes a good metallurgical bond with the substrate and the high cracking resistance.