Effects of substrate bias voltages on the erosion wear resistance of TiN coatings deposited by pulsed filtered vacuum cathode arc deposition

TiN coatings were produced on substrates of a hard metal at different bias by pulsed filtered vacuum cathode arc deposition assisted with ion bombardment. The erosion wear resistance of TiN coatings was investigated. The erosion wear was tested with a gas blast apparatus. In the test, TiN coatings were impacted at an impingement angle of 90° by angular SiC solid particles with an average diameter of 124um. The maximum depth of the erosion scar measured by the Veeco NT9300 optical profiler was used to evaluate the erosion wear loss of the coatings. The coatings proved to have lower erosion rate than the substrate material and consequently, the erosion rate increased significantly to the high level of the hard metal substrate after the coatings were penetrated. The results indicated that the TiN coating deposited at 150V bias had the lowest erosion wear rate and best wear resistance. The failure mechanism was revealed by examining the surface morphology of the coatings before and after the erosion test. The erosion wear of the TiN coatings behaved as typical brittle materials.