Measurement of the adhesion of silver films to glass substrates

The adhesion of thin silver films to glass substrates was measured using the topple test. The effects of the film thickness, the deposition temperature, the time after deposition and ion bombardment of the substrates on the adhesion were investigated. The values obtained using the topple test were compared with those obtained using the scratch test (the styli used for the scratch test were pencil leads of various hardnesses). The main results were as follows. (1) The adhesion was of the order of 107 N m-2. (2) The adhesion was independent of the film thickness between 820 and 2120Å. (3) The adhesion was almost independent of the deposition temperature below 200°C. (4) Ion bombardment of the substrates produced an appreciable improvement in the adhesion. The effect appeared gradually after deposition. (5) The adhesion of films measured 75 days after deposition increased by a factor of 2.5 compared with the initial values. (6) A close simple relationship was found between the results of the topple test and those of the scratch test.