Decorative optical coatings

Abstract

The paper gives a survey of current research on decorative coatings. In the first part the main deposition techniques as well as characterization techniques are discussed. The paper is restricted to decorative physically vapor deposited hard coatings with electrochemically deposited barrier coatings. The influence of stoichiometry, structure, and surface roughness on the colour of physically vapor deposited hard coatings is reviewed. In the last decades, a number of different coating deposition techniques have been developed. The demand for environmental compatibility of low cost large-scale production techniques has resulted in the development of combinations of physical vapor deposition and electroplating. Coating systems have been developed using NiPd and CuSn(Zn) instead of Ni electroplated coatings as interlayers, strongly reducing the allergy risk. New industrial applications demonstrate the increasing economic importance of decorative hard coatings.