Ni-based Composite Coatings Reinforced by TiB₂/WC Synthesized in Situ on Stainless Steel by Laser Cladding

The Ni-based composite coatings reinforced by TiB2 and WC were prepared on the stainless steel substrate by laser cladding.The coatings were analyzed by means of X-ray diffraction,X-ray energy dispersive spectroscope,scanning electron microscope and thermal shock experiment.The results indicate that the coatings were dense,smooth,uniform,free of cracks and pores,and had good adherence to the substrate.The coatings were composed of TiB2,WC and γ-Ni phases and the fine TiB2 and WC particles mainly dispersed at grain boundaries of γ-Ni dendrite and hindered the expansion of the grain boundaries.WC particles mainly dispersed at the middle and bottom zones after the laser cladding.TiB2 grains synthesized in situ were fine and mainly distributed at the upper zone.The coatings pocess a good metallurgical bond with the substrate and excellent cracking resistance.