Electrically conductive cermet has metal coating on particles - of refractory oxide forming conductive lattice

摘要

Electrically conductive cermet (I) consists of refractory oxide granules (II) with a thin coating of a gp. IVB-VIIB or gp. VIII metal (III). forming a conducting lattice which extends throughout the entire (I). Pref. (II) consists of Al2O3 and (III) is W or Mo. (I) can be formed integrally with an insulating cermet (IV) consisting of the same (II) and (III) and in the same vol. ratio. The claims over the use of the (integral) cermet for terminal cap or tube of an electric (discharge) lamp. (I) with a low (III) content can be used giving a coefft. of thermal expansion closely matching that of a refractory oxide ceramic, e.g. polycrystalline Al2O3. The fraction of (III) by vol is 0.045-0.2 pref. 0.067-0.2. For caps (IV) is used near the lamp envelope and (I) as zone(s) passing through this and holding the filament. For tubes (I) is used at both ends and (IV) in the middle or (I) is in strips along the inside of the tube.