Experimental and modelling techniques for assessing the adhesion of very thin coatings on glass

Abstract

The adhesion of very thin (<100 nm) coatings on glass is not easy to assess. A particular issue at the present time is the assessment of the adhesion of thin metal coatings sandwiched between dielectric layers in a multilayer stack as is used in solar control coatings. A range of experimental techniques have been developed for thicker coatings but they do not always give consistent results, particularly as the coating thickness decreases. In all cases the operating failure mechanisms must be identified and the correct methods for analysing the data produced must be selected. In this paper, the experimental techniques, models and atomistic simulations which can determine the interfacial adhesion of thin ZnO/Ag ceramic/metal layers have been investigated. Overlayer techniques, scratch and nanoindentation techniques, and double cantilever beam methods can give reasonable and consistent results which agree very well with the intrinsic interface adhesion obtained from atomistic simulations.