Tribology of carbonaceous films formed by ion-beam- assisted deposition of organic material

• Published in: Surface & coatings technology 1991-07, Vol.46 (2), p.233-243
• Main Authors: Hioki, T., Itoh, Y., Itoh, A., Hibi, S., Kawamoto, J.
• Format: Article
• Language: English
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/0257-8972(91)90166-T

By combining the vapour deposition of a silicone oil (pentaphenyltrimethyltrisiloxane) and simultaneous energetic ion irradiation, carbonaceous films (i-silicone films) 0.1-0.3 μm thick were coated on disc samples of hardened SUJ2 (AISI 52100). As the ions for irradiation, 1.5 MeV Ar +, 400 keVTi + were used. The frictional properties of the i-silicone coated disc, in particular the dependence of the friction coefficient μ on humidity, were tested with a pin-on-disc method using a hardened SUJ2 pin. All the i-silicone coatings prepared by using the three ion beams exhibited similarly low values of μ−0.05 in ambient atmosphere. In both air and nitrogen gas the i-silicone coating exhibited a low value of μ≈0.05 for a relative humidity range from 70% to 20%, the lowest humidity available. On the contrary, diamond-like carbon prepared by plasma- enhanced chemical vapour deposition displayed a value of μ≈0.2 for the same humidity range. In dry nitrogen, both the i-silicone and the diamond-like carbon exhibited an extremely low value of μ⩽0.02. Reasons for the moisture-insensitive frictional properties of i-silicone and features of the ion-beam-assisted deposition coating process of organic materials are discussed.