Study Of (Ti,W)C-C/Cu Grading Composite Coating By Laser Cladding

Gradient materials had multiple properties and structures at the same time.The properties of the materials can be tailored to specific applications.For graded materials,functionally graded phase-enhanced Cu-based composites had excellent metal electrical and thermal conductivity and high hardness and wear resistance due to the addition of a reinforcing phase.Therefore,the application in electrical contact materials had broad prospects.In this paper,two kinds of functional gradient composite coatings of TiC-C/Cu or WC-C/Cu was prepared on the surface of pure Cu by laser cladding technology,which made full use of the excellent properties of graphite and ceramic phase materials,and both a synergistic enhancement effect in the matrix,and functionally graded materials with a composition,structure and properties was gradually constructed.The effects of compositional gradient on the microstructure and properties of the two coatings were investigated.In addition,the electrical erosion and friction and wear properties of the two coatings were investigated.The main results are as follows:1.The process of preparing a TiC-C/Cu gradient coating was preferred,the TiC-C/Cu gradient coating has no new phase,and the reinforcement phase was well bonded to the Cu matrix interface.Along the construction direction of the gradient coating,the phase composition,distribution morphology are gradient.The Vickers hardness of the TiC-C/Cu gradient composite coating increases in a gradient,and the fracture exhibits a characteristic of ductile fracture to brittle fracture,which corresponds to the change of microstructure.2.The final composition of the WC-C/Cu gradient coating was the same as the added component,and no new phase was formed.The added reinforcing phase and the Cu matrix interface wewre free of defects and impurities.The increase in the gradient content of the reinforcing phase results in a gradient change in the microstructure and properties of the gradient composite coating.The strengthening mechanism of WC-C/Cu gradient composite coating was mainly due to the load transfer enhancement of WC particles,the strengthening effect of graphite C on crack propagation.3.In terms of electrical ablation performance,the ablation degree and ablation area of the electrode material prepared by TiC-C/Cu and WC-C/Cu gradient composite coatings increased when the current value increased.The TiC-C/Cu electrode exhibits better ablation resistance than the WC-C/Cu electrode.4.The tribological properties of the two gradient coatings were tested.The sliding speed,load and the increase of the current carrying value made the wear mechanism of the two gradient coatings complicated.According to the comprehensive friction and wear test,the wear of TiC-C/Cu gradient coating was relatively low,while the friction coefficient of WC-C/Cu gradient coating was relatively low.