Thermally Sprayed Multilayer Coatings as Electrodes and Dielectrics in High Efficiency Ozonizer Tubes

Abstract

This paper presents the results of metal dielectric multilayer structures based on aluminum alloys and several oxide ceramics respectively. It investigates thermomechanical and dielectric properties with regard to the use of different powders for thermal spraying as well as a high and a low energy gun for atmospheric spraying. The experimental work of this study is divided into two main parts: the selection of materials and the development of promising coating systems and the manufacturing and testing of novel ozonizer tubes. The investigated coating systems are analysed focusing the application in ozonizers. Therefore, a metallic electrode, an oxide ceramic and the dielectric properties of the metal-ceramic-composite are analysed. Finally, the appropriate metal-ceramic composites are tested in an ozonizer. Paper includes a German-language abstract.

Dielectric properties of CaTiO3 coatings prepared by plasma spraying

“…Porosity, splat sizes and its boundary character can also play a minor role and are responsible mainly for the behaviour of GSP coating. Plasma spraying broadens the technological variability in the production of dielectric ceramics [1][2][3][4] giving the possibility to cover substrates of various shapes made from various materials. [30][31][32] At the same time the role of microstructure of coatings is important to control.…”

“…Various works on dielectric properties of plasma sprayed titanate ceramics have been published, 4,5,6 but there is a lack of research comparing plasma sprayed samples produced with different spray techniques. Such a study has got to be done with advantage employing CaTiO 3 because it is a material well known and widely used as a dielectric in a sintered state.…”