Patent ID: 8310157

Claim:
A lamp comprising: a ceramic discharge vessel comprising a body portion defining a discharge space and leg members extending therefrom; electrode assemblies comprising: conductors carried by bores of the leg members, at least one of the conductors being bonded directly to the respective leg member within the bore by sintering a ceramic body, without interposing a glass sealing material intermediate the conductor and the bore of the ceramic body, to shrink the ceramic body onto the conductor forming a heimetic seal therebetween to form an airtight seal, the at least one conductor comprising: a core formed from an electrically conductive metal, the core including at least one of the group consisting of Nb, Ta, Re, and Os, and at least one of an oxidation-resistant layer and a corrosion-resistant layer on the core, the core having been heated to increase a grain size of its surface prior to covering the core with the at least one of the oxidation-resistant layer and the corrosion-resistant layer, and electrodes electrically connected to the conductors and extending into the discharge vessel; and an ionizable fill sealed within the vessel, wherein in the heating of the core to increase the grain size, the core is heated at a temperature of at least 1400° C.