摘要 |
An electrically conducting cermet for use in a closure assembly in a high pressure sodium discharge lamp which cermet comprises a sintered compact of refractory oxide granules and a conducting network extending throughout the cermet wherein said network is provided by a layer of niobium and, optionally, at least one other specified metal. The cermet is, because of the niobium content of the metallic network, permeable to hydrogen and lamps incorporating this cermet can therefore be stabilized in acceptable times. |