Electrically Conductive Plasma Sprayed Oxide-Metal Coatings on Glass Ceramic Substrates

The manufacturing of insulating and electrically conductive functional coatings on glass or glass ceramic substrates by thermal spraying is of outstanding interest for a wide range of industrial applications, like ozoniser tubes, solar absorbers or cooking plates. However, due to the specific properties of such substrate materials, i.e. low or even negative CTE, low heat conductivity and inability to deform plastically, modified production processes in comparison to the established coating operations on metal surfaces are required. In the proposed approach, oxide ceramic as insulator and different metal alloys as conductive layers are deposited on glass ceramic plates by the APS technique. The use of grit blasting on glass ceramic coupled with optimized thermal pre-treatment is studied in order to improve the adhesion and mechanical stability of the coating system. For the deposition of complex shaped conductive layers, robot assisted coating processes as well as the development of new masking concepts are required. The influence of different process parameters on coating properties and residual stress distribution through coating and substrate is analyzed.