The effect of applying a rounded stylus to thin metallic films on glass substrates has been investigated using diamond and steel styli with tip radii of approximately 25 μm and loadings of up to 230 g. The films were vacuum-deposited indium, tin, lead, gold, copper, aluminium, nickel, chromium and molybdenum of various thicknesses up to 3·2 μm. Scanning electron microscope and optical interference microscope observations showed that the process of scratch formation was generally very complex and varied with the film material, indicating that it is not possible to deduce absolute values of adhesion forces using a simple general theoretical model. The method can, however, be used with caution for qualitative comparisons under certain restricted conditions.

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The effect of oxygen, present during film formation, on the structure and superconducting properties of tin films vacuum deposited on glass has been studied for substrate temperatures during deposition in the ranges of 23-30°C and 63-91°C.In both temperature ranges, in general, an increase in oxygen pressure decreases crystallite size and electron mean free path; it increases superconducting critical magnetic field value and width of transition but decreases the superconducting temperature transition width.The higher substrate temperatures produce films with larger crystallites and thin intercrystalline regions; these show hysteresis in the superconducting magnetic field transition and have higher values of critical field and critical current, in excess of those theoretically predicted.

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