Plasma CVD of alumina-Unsolved problems

The investigations clearly demonstrated that activating the process gas by plasma lowers the temperature needed for the formation of hard alumina coatings. The properties of the alumina coatings depend strongly on process parameters like temperature, plasma power and process gas composition. Higher plasma power as well as certain additives to the process gas favour the formation of hard alumina (α-phase) at lower temperatures and suppress the formation of softer alumina modifications. At the present stage, the process is still not sufficiently uniform. Furthermore, certain types of damage in the coatings were observed.