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2000
Conference Paper
Titel
Abrasion resistant coatings on plastic by PVD high rate deposition
Abstract
Plastic materials have optical clarity and the processing benefits of a thermoplastic, but lack of abrasion resistance. Al2O3 as well as SiOX layers perform very well as clear abrasion resistant layers. The typical layer thickness ranges from l µm to 6 µm. High deposition rates at an adequate layer quality can be reached by application of the Hollow Cathode Activated Deposition (HAD) process. The HAD process is based on the reactive evaporation of oxide or metal with high rates in combination with a hollow cathode plasma activation.The hollow cathode plasma source generates an arc discharge plasma with very high plasma densities in the order of 1012 cm-3. For insulating substrates a high self bias potential of about 15 V is obtained. The typical deposition rates are 100-150 nm/s for Al2O3 and 300-600 nm/s for SiOX. The deposited layers show a dense, amorphous structure and the microhardness (measured by nanoindentation) amounts to 6 GPa for Al2O3 layers respectively 3 GPa for SiOX. Regardless of the different hardnesses the abrasion resistance performs for both oxides very well. Therefore the mentioned oxides are well suited to improve the abrasion resistance of plastic surfaces. Some practical applications will be derived. Finally the industrial production process will be discussed for the oxide deposition on plastic films as well as on plastic sheets. The plant productivity and the coating costs for typical layer thicknesses will be estimated.