Adhesion of thin films

Özenbas, M.
Tan, C.
The periodic cracking technique for determining the work of adhesion of thin metallic films was applied to two different substrate systems which were metallic substrates (Al, Cu and steel sheet) and a polymeric substrate (ABS, acrylonitrile butadiene styrene). The original model assumes elastic behaviour of the composite and is insufficient for such an application since the substrates exhibit plastic deformation before failure takes place. The model, however, is quite sufficient for obtaining relative magnitudes of the work of adhesion values. The films were vacuum deposited at <10-5 Torr onto the substrates. The adhesion increased with increasing substrate temperature and cleanliness of the substrate surfaces. The adhesion values were higher on the electropolished surfaces in comparison to the rough ones. To support the results obtained from the periodic cracking technique, microhardness measurements and tape tests were also performed on the same specimens.