Research On Ni-WC Composite Material Prepared By Ultrasonic Auxiliary Pulse Electroforming And Its EDM Properties Of Resistance To Electrical Erosion

Electronic Discharge Machining is a kind of non-traditional machining technics,based on the instantaneous high temperature created by the pulse spark discharge between the tool electrode and workpiece electrod to removal of metal material.EDM tool electrode consums some energy in the EDM process-cycle,resulting in tool electrode loss,and affecting the working accuracy.Therefore,improving the anti-corrosion properties of EDM electrode material is very important to extend the electrode's life and improve the working accuracy.In order to improve the anti-electrical erosion of the EDM electrode material,use the principle of composite electroplating in this dissertation,the Ni-WC composite coating with excellent anti-electrical erosion was prepared on the surface of copper electrode,and the preparing conditions and properties of composite coating were studied in this dissertation.The main works completed and conclusions were presented as follows:(1)Optimization of process parameters for Ni-WC composite electrode position.The content of WC in the composite plating layer was set to the measuring indicators.Composite plating solution is formed by adding WC particles to the plating solution,by changing experimental conditions and technological parameters,investigations on influences on the amount of WC in the plating solution?current density ?experimental period and bath temperature.the orthogonal tests are performed and the optimum process parameters for preparing Ni-WC composite coatings were obtained via the orthogonal tests.Preliminary results the optimum process parameters to prepare the Ni-WC composite plating,compare all the process parameters to obtain a significant effect sequence on the WC content in composite plating layer: the amount of WC in the plating solution>current density >experimental period > bath temperature.Based on the results of orthogonal experiments,optimized technical conditions results from signal factor analysis is as follows: WC in the plating solution is 35g/L,current density 3A/dm2,pulse frequency2000 Hz,ultrasonic power 40 W,duty ratio 0.7,bath temperature 40?,experimental period4 h.The Optimal performance of of the Ni-WC composite coating prepared under the optimum process conditions is: the highest content of WC in the coating with fine and dense structure.(2)Performance test of composite plating layer.Electrochemical corrosiontesting,saltspraycorrosionensile testing,microshardness testing were carried out on the Ni-WC composite coating.And the performance of Ni-WC composite coating is optical when WCin the plating solution is 35g/L.Under the optimum process conditions,the microhardness of the composite coating is 322.4HV(3)Performance test of anti-EDM electrical erosion.EDM experimental results show that under the high electrical parameters,the plating Ni-WC composite electrode with the optimum process conditions hs the best anti-electrolytic corrosion resistance and hole's conicity.