Tribological and magnetic characterization of fluorosilanes on cobalt surface

Abstract

In this paper, we present a study of tribological properties of fluorosilane monolayer on magnetic surface. The used fluorosilane was 1H, 1H, 2H, 2H perfluorodecyltrichlorosilane (FDTS), and the used magnetic material was a cobalt film. The effectiveness of modification of the cobalt surface by FDTS was monitored by the measurement of the wetting contact angle and the surface free energy. The increase of surface hydrophobicity was observed upon the modification by reducing the surface free energy and increasing the wetting contact angle. The nanotribological properties were characterized by means of adhesion, friction and wear, using atomic force microscopy (AFM). The cobalt surface modified by FDTS exhibits lower values of adhesion and the coefficient of friction in comparison with those for the unmodified surface. It was also found that FDTS effectively reduces wear of the system. We also investigated the magnetic structure of the cobalt film before and after modification by FDTS. The magnetic structure was composed of maze stripe domains magnetized perpendicular to the film surface, as revealed by magnetic force microscopy (MFM). The domain structure of the modified cobalt film was practically the same (in character and in size) as that observed for the bare cobalt film.