HID lamp electrode comprising barium (yttrium or rare earth metal) tungstate or molybdate

摘要

For HID lamps, and particularly high-pressure mercury or sodium- mercury HID lamps, the electron-emissive material portion of the lamp electrodes is M. sub.3 M'.sub.2 M"O.sub.9 wherein M is alkaline-earth metal and at least principally comprises barium; M' is yttrium, a lanthanoid series metal, or any mixtures thereof; and M" is tungsten, molybdenum, or mixtures thereof. The specified material is very stable and highly emissive.