| AVS 59th Annual International Symposium and Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | H. Nishi, Kogakuin University, Japan |
| Authors: | H. Nishi, Kogakuin University, Japan K. Harada, Kogakuin University, Japan I. Takano, Kogakuin University, Japan |
| Correspondent: | Click to Email |
DLC (Diamond-like carbon) classified in new materials is amorphous carbon including hydrogen and has the similar property to diamond. DLC films were formed by the ion beam evaporation method in the early 1970's and after that have been manufactured by various methods. Because the representative property of DLC shows the high hardness and low friction coefficient, DLC is applied in various fields such as motor parts or tools. The ion beam assisted deposition method has many parameters on the film formation condition in comparison with other dry process methods. Therefore this method was anticipated in production of new characteristics such as a high adhesion film.
From the result of our research, DLC thin films prepared by the ion beam assist method using an N2 gas showed the excellent low friction coefficient in the atmosphere. In this study, the behavior on friction in a vacuum of those DLC films was investigated. The DLC films were formed using N2+ ion beam assisted deposition in a toluene (C7H8) atmosphere. The formation conditions of DLC films were changed with an ion beam current density and an accelerating voltage. Stainless steels (304SS) were used for the sample substrate. The mechanical properties of hardness and friction coefficient were measured using the dynamic micro knoop hardness tester and the ball-on-disk tribotester respectively. Atomic concentration and structure of the films were investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The friction coefficient in a vacuum was measured under 5 x10-4 Pa. The conditions of the ball-on-disk test were 0.98 N in a weight and 135 rpm in a sliding speed.
The suitable friction property of DLC films was obtained by the condition with an accelerating voltage of 5 kV at a current density of 10 μA/cm2. The minimum friction coefficient in a vacuum was 0.016 for an SUJ2 ball of the counter material, however, the DLC thin film started to cause partial peeling-off in a sliding distance of 52 m. It is anticipated that the property in a vacuum of these DLC films is applied in space technology.