The Influence of Methyl Group Content on Tribological Properties of Organo-Silica Thin Films

Solid thin films of lubricants are often used as protection coatings of working surfaces in frictional contacts. Usually, these films have to contain stable and tribologically active additives like, for example, molybdenum disulphide or graphite. In this work chemically modified silica was investigated as a potential matrix of nanocomposite lubrication films. The sol-gel technique was used with tetraethoxysilane (TEOS) and triethoxymethylsilane (TEMS) as precursors of organo-silica thin films. Dip coating was applied as the method of film formation. Introducing a methyl group into silica by adding TEMS during sol-gel synthesis of silica films strongly increases their adhesion to the coated materials, which gives possibilities for using them on steel surfaces. The chemical properties of films synthesised by the sol-gel technique were examined by FTIR spectroscopy with the use of the transmission method. The surface topography was imaged and frictional features of organo-silica films were examined by Atomic Force Microscopy (AFM).