Structural and functional properties of nanocomposite Au-WO3 coatings

In this study several Au-WO3 nanocomposite coatings were deposited by reactive magnetron co-sputtering and characterized with respect to their chemical composition, structure, microstructure and mechanical and optical properties. The nanocomposites consist of a dual phase system of Au nanoparticles dispersed homogeneously in an amorphous WO3 matrix, with compositions ranging between 0 and 11 at.% Au. To enhance the surface plasmon resonance effect in the coatings, the growth of Au nanoparticles was stimulated by applying a thermal annealing treatment at different temperatures up to 500 degrees C. The annealing treatments promoted the crystalization of the WO3 matrix. The hardness of the coatings remained close to 4.5 GPa, irrespectively of the Au content and annealing temperature. As a result of the microstructural changes in both the nanoparticles and matrix, surface plasmon resonance effect was successfully enhanced and different colourations were obtained in the coatings. (C) 2015 Elsevier B.V. All rights reserved.