Effects of pulsed bias duty ratio on microstructure and mechanical properties of TiN/TiAIN multilayer coatings

摘要

TiN/TiAIN multilayer coatings were deposited on M2 high speed steel by a pulsed bias arc ion plating system. The effect of pulsed bias duty ratio on the microstructure, mechanical and wear properties was investigated. The amount of macroparticles reduced with the increase of the duty ratio. The surface roughness was 0.0858μm at duty ratio of 50%. TiN/TiAIN multilayer coatings were crystallized with orientations in the (111), (200) (222) and (311) crystallographic planes and the microstructure strengthened at (111) preferred orientation. At duty ratio of 20%, the hardness of TiN/TiAIN multilayer coatings reached a maximum of 3004 HV, which was 3.2 times that of the substrate. The adhesion strength reached a maximum of 77 N at 50% duty ratio. Friction and wear analyses were carried out by pin-on-disc tester at room temperature. Compared with the substrate, all the specimens coated with TiN/TiAIN multilayer coatings exhibited better tribological properties.