Transparent glass-ceramic coatings: Property distribution on 3D parts

Transparent protective coatings consisting of a graded mixture of SiO2 and Al2O3 are deposited by electron beam evaporation as a finish layer of a dec orative coating system on light metal car wheels. The base coating of the c oating system is a gloss lacquer with a Cr reflection layer. The typical 3D character of the car wheels leads to a distribution of coating properties over the wheel profile, which are evaluated by thickness measurements, dept h-sensing indentation measurements and by depth profiling of the chemical c onstitution. Results of application tests are additionally summarised. Pros pective and critical points of the coating system are outlined. (C) 2000 El sevier Science S.A. All rights reserved.