Abrasion resistance of thin film coatings as measured by diffuse optical scattering

In this study, the abrasion resistance of a reflective thin film multilayer system consisting of Chromium Nitride (CrNx) layers deposited on specially prepared coated polymeric substrates is presented. The abrasion resistance is quantified by the Bayer abrasion test, and then correlated with the physical properties of the film. Their resistance to abrasion is identified as being defined partially by the microstructure of the layers within the multilayer system. Relative measures of the abrasion resistance are made by quantifying the surface roughness in the specific case where the substrate is the same (hardness and elastic moduli) and the elemental and phase composition of the coating is the same. Importantly, the optical measurement of the diffuse reflectance is used to assess the relative structure of the coatings prior to the abrasion test. By doing so, a useful, non-destructive technique is presented for characterising the relative abrasion resistance of sputtered thin film coatings.