Laser Cladding Ni-base Composite Coatings Reinforced by In-Situ Synthesized Multiple Carbide Particles

摘要

Nickel-base composite coatings reinforced by in situ synthesized multiple carbide particles were fabricated on mild carbon steel through powder-feeding laser cladding. The results indicate that laser cladding is an effective approach to fabricate required coatings, which combines heat and corrosion resistance of nickel based superalloy, good hardness of the reinforced hard phase, and low cost of commercial spraying alloy powders. This offers a potential strengthening solution for wearing components which works in high temperature and caustic environment in industry. The composite coatings exhibit fine shape and are free of pores and cracks. The microstructure of the coatings is mainly composed of γ-Ni dendrite, interdendritic eutectic and dispersed multiple carbide particles. With variation of the amount of strong-carbide-formation elements, there are significant changes in the morphology of microstructure and the size, distribution and density of precipitated particles. The corresponding changes in the microhardness, friction and wear properties of the coatings were investigated by means of scanning electron microscopy, X-ray diffraction and tribology test.