Enhanced discharge and surface properties of (Ti,AlCr)N coatings by cleaning cathodic-arc chamber

Abstract

In the PVD processes, the clearance of the chamber wall directly affects the microstructure and surface properties of the coatings. The (Ti,AlCr)N coatings are fabricated on M2 high-speed steel (HSS) and Si (100) by cathodic arc evaporation with the vacuum chamber cleaned or uncleaned. With the chamber cleaned, the arc discharge was enhanced with a higher intensity of optical spectrum and the concentration of residual oxygen was decreased. The clearance of chamber wall altered the external behavior of power supply and a larger input power was achieved. The average substrate ion current was increased by 13.0% and a larger Ebi was observed implying increased densification of coatings. A thicker coating was obtained with less surface defects (macroparticles). Consequently the microstructure and surface properties of (Ti,AlCr)N coatings have been improved with higher hardness, lower friction coefficient and superior adhesion strength between the coatings and substrate.