A heat resistant sealing composition, a method of making this composition, a method of making a ceramic-cermet seal in electric discharge devices and the device thus obtained

摘要

This sealing composition comprises a rare earth oxide, such as lanthanum oxide, and boric oxide, preferably together with minor amounts of phosphorus pentoxide, aluminium oxide and magnesium oxide.;Preferred compositions comprise 55 to 95% lanthanum or other oxide, 5 to 45% boric oxide and 0 to 5% magnesium oxide. The compositions can be made by mixing the oxides, or appropriate salts, calcining the mixture at up to 1200°C and crushing it to a powder. They may be used as frits in a slurry or formed into pressed elements such as discs or wasbers. Sealing can be accomplished by heating the surfaces to be joined, together with the interposed sealing composition, to a temperature between 1100 and 1650°C.