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Nickel based composite coatings reinforced with WC particles were fabricated using plasma transferred arc welding(PTAW) technique considering variable welding current and preheating operation. A detailed characterization was conducted to investigate the dissolution mechanism of WC particles and the microstructural evolution of the composite coatings . Results indicated that an increase in the welding current and preheating temperature result in a corresponding rise in dilution rate . Alloying reaction occurred between WC particles and the liquid nickel matrix within the molten pool, WC particles experienced decomposition-dissolution process, contributing to the formation of WC x and M x C y precipitated carbide phases. The trigonal and hollow hexagonal prisms are the basic three-dimensional morphology of in-situ synthesised WC and M 7 C 3 , respectively. Hard WC particles and precipitated carbide phases promote the hardness of the composite cladding coatings significantly together. The average hardness of the hard coating is between 669 and 756 HV, which is at least 2.4 times that of the substrate. • Nickel based coatings reinforced with WC particles were fabricated using PTAW. • The influence of welding current and preheating operation were investigated. • WC particles experienced decomposition-dissolution reaction inside the molten pool. • Morphology evolution of in-situ WC and M 7 C 3 crystal was revealed. • WC x and M x C y carbides and original WC particles improve the hardness together.
Zhang et al. (Wed,) studied this question.