Determination of thin film hardness for a film/substrate system

A simple model for determining the film hardness for the composite hardness of a film/substrate system is developed. On the basis of volume law and current models, the model can be used without requiring any additional material property for amorphous, multicomponent and multiphase coatings. As the cause of indentation size effect (ISE) is taken into account, the ISE of the film is neglected at a high depth/thickness ratio and the introduction of Meyerʹs equation is avoided. The hardness values of TiC/a-C:H in situ composite films by PECVD are assessed with the model by controlling the film thickness and indenting under fixed loads, the results obtained for the films coated on Si(100) and Corning 7059 are 1479 and 1681 kg/mm2 respectively.