Formation of electrodeposited Ni-TiAlN/Si3N4 composite coating: effect of Si3N4 concentration

摘要

The Ni-TiAlN/Si3N4 composite coating has been investigated.The composites were deposited at fixed electrodeposition current of 3 mA for 15 minutes.The electrolyte consists of 0.49 mol/1 H3B03,0.17 M MC126H2O,0.38 M NiSO46H2O,0.2 gr/lit SDS,2 gr/lit A1N and 2 gr/lit TiN.The concentration of Si3N4nanofiber was varied into 10,20 and 30 gr/lit.The electrodes used were Pt wire as counter electrode,AgClwire as reference electrode and tungsten carbide(WC)rod as working electrode.The surface morphology and composition of composites were characterized by using Scanning Electron Microscopy(SEM)dan Energy Dispersive Spectroscopy(EDS),respectively.The crystal structure of composites was characterized by using X-Ray Diffraction(XRD)and the hardness was tested by using Vickers hardness tester.The results showed that the composite coating surface morphology was finer as the increase of Si3N4 concentration due to the decrease of Ni crystal size.The increase of S3N4 concentration indicating the formation of stable structure composed of Ni-TiAlN/Si3N4 caused the increase of the coating hardness.