Abstract
This paper describes a process that has been developed for producing thick composite coatings with friction and wear properties that were once only achievable in diamond-like carbon (DLC) films. The process is based on cold spraying and the use of surface modified metallic powders. In this investigation, two such powders were prepared by placing either copper or titanium particles on a negatively biased stainless steel tray and then coating them with a DLC film by pulse plasma chemical vapor deposition. The powders are then cold sprayed onto aluminum plates, creating metal-matrix composite coatings. The thickness of the Cu-DLC composite coating is 250 µm and that of the Ti-DLC coating is 435 µm. In each case, the presence of dispersed DLC in the metal matrix was verified by Raman spectroscopy. Sliding wear tests were also conducted, revealing that the Cu-DLC composite has a lower coefficient of friction than copper film, while the Ti-DLC composite has lower specific wear rate than titanium film.
