Ti-TiN Films Prepared by Cathodic Multi Arc Ion Plating on Magnesium Alloy AZ91C

TiN films grown on Ti as interlayers were prepared on AZ91C magnesium alloy substrate by cathodic multi arc ion plating.The surface morphology,microstructure and hardness of the films were examined using high-resolution scanning electron microscope(SEM),X-ray energy diffraction spectrometers(EDS)and microcharacter hardness tester.The results show that TiN films with good performance can be obtained on the properly pretreated magnesium substrate by the multi arc ion plating technique.The adhesion force between the film and substrate was over 130 mN,and the complex hardness of the films was about 500 HV whereas that of AZ91C magnesium alloy was about 125 HV.The neutral salt spray accelerated testing indicated that corrosion rate of magnesium alloy after treated by this method declined significantly under ASTM-117 standard test condition.The surface of the films was not corroded obviously after salt spray test for 200 h.Vacuum multi arc ion plating technique can be applied to the area of magnesium alloy surface protection.