Innenbeschichtung von Rohren, Schläuchen und Kapillaren

Coating inside tubes becomes increasingly important for fluidic applications, in which inner surfaces are strained tribologically by flowing liquid and scratching of particles. The developed process for tube coating, presented in this work, is based on novel setup with a discharge in between two electrodes at the ends of the tube, which results in fragmentation of the reactive precursor, delivered through one of the electrodes, and in film deposition. Igniting plasma inside the tube, the tube walls are the barrier to the atmosphere. Especially, pulsed DC discharges for plasma polymerization in such alignment lead to good coating results as shown in the workfocusing on deposition in pure and mixed hexamethyldisiloxane (HMDSO), acetylene (C<inf>2</inf>H<inf>2</inf>), and O<inf>2</inf> atmospheres. Chemical binding, wetting and tribology are highly influenced by the choice of gas mixtures, resulting in either hydrophilic or hydrophobic behavior for SiO<inf>2</inf>-Hke and Si-doped polymer-like carbon films, respectively. Tribologically, reciprocating sliding tests under high loads against Al<inf>2</inf>O<inf>3</inf> counterparts revealed high wear resistance, especially for low-friction, Si-free polymer-like carbon films.