A study on film growth and tribological characterization of nanostructured C-N/TiNx multilayer coatings

Coatings of C-N/TiNX composite multilayers, where X less than or equal to 1 in the nanometer range, have been deposited in a reactive sputtering system with side-by-side cathodes of titanium and carbon. Coatings were deposited on samples of tungsten carbide, and high-speed steel on a substrate holder rotating with variable speed from 2 to 28 rpm. Sputtering was performed in nitrogen/argon with a constant Ar flow of 25 seem. The individual bilayer thicknesses were derived from the deposition rate and the rotation speed. Power for the Ti and C cathodes was kept constant at 1200 W. Deposition parameters were selected from curves showing total sputtering pressure and the voltages of the Ti and C sputtering cathodes versus the nitrogen gas flow. The acoustic emission scratch test developed for coating-adhesion measurements was used as a coarse rest For coating evaluation. Particularly, the acoustic emission signal will be discussed and the friction coefficient for sliding against a Si3N4 ball in a ball-on-disk tribometer was measured, and showed a strong dependence on the deposition parameters. (C) 1997 Elsevier Science S.A.