Microstructure and properties of ESD coating on aluminum alloy

Using silicon bronze electrode,2A12 aluminum alloy surface was strengthened by electrospark deposition process.The microstructure,element distribution and phase structure of deposited coating were analyzed by scanning electron microscopic,energy-dispersive spectrum and X-ray diffractometer,respectively.Furthermore,the microhardness distribution and wear resistance of deposition coating were studied by microhardness tester and abrasion tester,respectively.The results show that the deposition coating has an average thickness of about 30 μm and forms metallurgical bonding with the substrate.The deposition coating is mainly composed of Cu-Al intermetallic compounds,its microhardness can reach 578 HV.Compared with the 2A12 aluminum alloy substrate,the wearing volume loss of deposition coating is less than one fifth of the substrate.The surface performance of 2A12 aluminum alloy is improved obviously.