[15a-A26-1~11] 6.2 Carbon-based thin films

[15a-A26-11] Friction coefficient between DLC coated ball and a-BCN:H coated plate

〇Nasa Kawagoshi¹, Tetsuya Yamamoto², Naoto Ohtake¹, Hiroki Akasaka¹ (1.Tokyo Tech, 2.Nippon Shokubai)

Keywords:Diamond-like carbon films, hydrogenated amorphous Boron Carbon Nitrogen, friction coefficient

Diamond-like carbon (DLC) films has many excellent mechanical properties such as high hardness, high wear resistance, and low friction coefficient. Therefore, DLC film has been applied to the surface of a sliding member as a solid lubricant film. It is suggested to deposit hard film on opposite material to reduce wear amount of sliding surface. However, wear amount increases when use similar DLC film. Therefore, in this study, hydrogenated amorphous Boron Carbon Nitrogen (a-BCN:H) film was deposited on opposite material, and evaluated friction coefficient between DLC film and a-BCN:H film. DLC film was deposited on SUJ2 ball of 6mm in diameter and a-BCN:H film was deposited on Si(100) by the pulse plasma CVD method. DLC film deposited from C₂H₂ with a flow rate of 15 cm³/min, for which the deposition time was approximately 1 h. A pulsed bias voltage of -4.5 kV with a frequency of 14.4 kHz was applied to the substrate. The pressure was 3.0 Pa. The balls were moved during DLC film deposited. Amorphous BCN:H film deposited from C₂H₂ with a flow rate of 15 cm³/min and trimethyl borazine, for which the deposition time was approximately 1 h. A pulsed bias voltage of -3.5 kV with a frequency of 14.4 kHz was applied to the substrate. The pressure was 10.0 Pa. The balls were moved during DLC film deposited. Obtained film was evaluated for the chemical composition by the Glow discharge optical emission spectrometry (GD-OES) method, and the friction coefficient by Ball on disk (BoD) test.The friction coefficient and wear amount between SUJ2 ball coated DLC film and a-BCN:H film was lower than between SUJ2 ball and a-BCN:H film. Furthermore, DLC film peeled off when opposite material was Si(100), however, DLC film didn’t peel off when opposite material was a-BCN:H film. Furthermore, the friction coefficient and wear amount were the lowest when opposite material was a-BCN:H film which contained more carbon.According to the above results, the friction coefficient and wear amount between DLC film and a-BCN:H film changes by composition of a-BCN:H film.It was suggested that the friction coefficient can be controlled by the composition of the film and wear amount can be reduced.