New DLC Technologies
S. Mikhailov1, C.Meunier2, S.Goloviatinski3, E.Sheleg4, V.Sheleg5, C.Petit6
1 He-Arc, IMA, 17 Eplatures-Grise, 2300 La Chaux-de-Fonds, Switzerland
2 FEMTO-ST, UMR 6174 CNRS, Université de Franche-Comté, 4 place Tharradin, BP71427 25211 Montbéliard, France
3 Swissnanocoat SA, 17 Eplatures-Grise, 2300 La Chaux-de-Fonds, Switzerland
4 Creepservice Sarl, 22 Sentier du Ministre, 2014 Bôle, Switzerland
5 SZOS, 78 Kolasa, 231042 Smorgon, Belarus
6 Socrate Industrie Sarl, Zone Artisanale Dolines, 25500 Le Bélieu, France
By the choice of the excitation mode (laser, trigger) of the arc discharge, and by using higher energy conditions (100eV / ion [1]), new carbon layers were accomplished. These DLC layers present very interesting characteristics like high smoothness (without droplets), hydrogen-free and low sp2 content in the order of 25 %, estimated by XPS. Raman spectra show a very disordered nature of the sp2 bonding and XRR measurements reveal high density (up to 3). These layers display high hardness up to 80 GPa with an apparent elastic modulus more than 600 GPa and a coefficient of friction about 0.12. They exhibit an infrared transparency and a very good level of biocompatibility.
Method for deposition of these particular DLC coatings consists of a combination of processes: PVD +CVD + low energy ion implantation. Three different sources are used: low energy ion gun for etching / polishing / implantation for the surface preparation, filtered arc sources (x2) for metal deposition (with reactive gases) if a mechanical buffer is needed for a good adhesion on substrates, and pulsed arc carbon source for the DLC coatings deposition (with an adjustable filtering of macroparticles).
This high performance and cost efficient technology enables to improve considerably service life time of micro tools, needles, other components. Obtained DLC show an ultra low friction and increased breakage resistance. They improve anticorrosion, anti-sticking and biocompatibility characteristics. Surface temperature during the treatment is low (<70°). Flexion tests with micro drills of 0.1mm diameter show >40% improves of a breakage resistance.
[1] Robertson J, Materials Science and Engineering: R: Reports, 37, 4-6, 24 2002, 129