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Thin alumina-based ceramics are promising materials for many applications due to their excellent physical and chemical properties. An attractive and modern application is the use of such materials as dielectric barrier layers for advanced types of 'cold' electric plasma sources based on dielectric barrier discharges. In this study, we compare three alumina-based ceramics with respect to their properties for this particular application. We focus on basic electric properties mainly, e.g. permittivity and loss angle. Also, the discharge ignition voltage and quenching voltage are studied in detail because of their importance for the practical performance of dielectric barrier discharges.

The machinability of newly developed zirconia ceramics for CNC milling was investigated. The zirconia blanks were prepared by the gelcasting method and tested in the green and two pre-sintered states. All blanks exhibited uniform sintering shrinkage in all directions. The blanks were investigated from the viewpoint of surface milling roughness, quality of milled edges and sharp tips, and machinability of thin structures. The best milling results were obtained for the blanks pre-sintered at 900 °C/1 h. Mechanical properties of zirconia blanks, such as biaxial flexural strength, microhardness, indentation elastic modulus, and fracture toughness were determined in the green and pre-sintered states (900 °C/1 h and 1100 °C/1 h) and the