Thermally sprayed Al2O3 coatings having a high content of corundum without any property-reducing additives, and method for the production thereof

US8318261B2 · kind B2 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Filofteia-Laura Toma · Dresden, DE
• Lutz-Michael Berger · Dresden, DE
• Carl Christoph Stahr · Alzenau, DE
• Tobias Naumann · Dresden, DE
• Stefan Langner · Dresden, DE

Key dates

• Filing date: May 28, 2009
• Grant date: Nov 27, 2012
• Expiry date: May 28, 2029

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C4/129
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

The disclosure provides a method of producing thermally sprayed Al2O3 coatings having a high content of corundum without any property-reducing additives. The coatings may be utilized particularly in the field of electrical insulation, as a dielectric, and as protection from wear. The thermally sprayed Al2O3 coatings have a porosity of no more than 19%, and a high content of α-Al2O3 (content of corundum) of at least 72% by volume. The coatings have a specific electrical resistance of >1·1012 Ohms·cm, and a purity of >97%. The production of said coatings is carried out utilizing aqueous or alcoholic suspensions made from substantially pure α-Al2O3, having a grain size of >100 nm by thermal spraying.