Fast CO_2 laser firing of sol-gel SnO_2:Sb coatings

摘要

In recent years the coating technology based on the sol-gel process has revealed a great reliability in industrial application. In this method the films are usually prepared by dip or spin coating and afterwards are dried and fired in two separate processes using a furnace [1,2]. The main advan-tages of these techniques compared to other coating technologies such as sputtering, physical vapour deposition (PVD) or chemical vapour deposition (CVD) is that no vacuum installation is needed and that it is possible to produce very homogeneous films at a reasonable price even at large scale. A further benefit is the great variety of oxide materials that can be produced. Drawbacks are the high tempera-ture needed for the densification of the coatings, usually around 500 °C and if several layers are needed, as for instance to produce interference filters or to increase the coating thickness, the substrate has to be heated up and cooled down between each coating. For flat-glass coating, the maximum attain-able cooling rate is the speed-limiting factor of the coating process.