Title: Mechanical and tribological properties of diamond-like carbon and DLC:Si coatings deposited on stainless steel/WC-Co substrates
Authors: Ricardo Assunção Santos; Sérgio Souza Camargo
Addresses: Programa de Engenharia Metalúrgica e de Materiais, COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil ' Programa de Engenharia Metalúrgica e de Materiais, COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Programa de Engenharia de Nanotecnologia, COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Abstract: The mechanical and tribological properties of diamond-like carbon (DLC) and silicon-containing DLC (DLC:Si) films deposited onto stainless steel/WC-Co substrates by radio frequency plasma enhanced chemical vapour deposition (rf-PECVD) were investigated at two different temperatures. DLC films presented the highest adhesion to the substrates, decreasing with the silicon content, due to the higher compressive stress and fracture toughness of DLC. The low silicon content DLC:Si films present higher friction coefficients and wear rates at 22°C, due to the continuous oxidation of the films during the tests, leading to the strong formation of oxide wear debris. At 110°C the friction coefficient and wear rate of the low silicon content DLC:Si films are strongly reduced due to the formation of a thin lubricating C-Si-O transfer layer. In case of the high silicon content DLC:Si films, the mechanisms of friction and wear reduction are not present because the films present a silicon carbide-like structure.
Keywords: diamond-like carbon; DLC; silicon-containing diamond-like carbon; coatings; mechanical properties; nanoindentation; tribology; friction coefficient; wear; scratch test; adhesion.
International Journal of Surface Science and Engineering, 2018 Vol.12 No.4, pp.259 - 276
Received: 11 Sep 2017
Accepted: 20 Mar 2018
Published online: 07 Nov 2018 *