Abstract: High pressure discharge lamps have discharge tubes of ceramic material having end caps into which electrodes are mounted on fixed shanks. The invention provides a preferred construction for mounting on electrode shank or an external conducting member in a cermet end cap. A metal coil is fixed in a respective opening in the end cap and supports the respective shank or conductor therein. Preferably the cermet is pressed into the desired shape with an aperture in it. The coil is inserted into the aperture so that after sintering the coil is fixed into the sintered cermet.

Abstract: The invention relates to electric incandescent lamps having a gas fill containing halogen. The internal surface of the lamp envelope and optionally also the exposed surface of internal components of the lamp are protected from attack by halogens including fluorine by a continuous imperforate coating composed of a metal oxide resistant to halogen attack. In order to achieve the necessary degree of continuity of the coating the oxide is formed in situ from a compound of the metal deposited as a solution on the surface. The preferred oxide is alumina, the other oxides of polyvalent and transition metals, including metals of the lanthanide series may be used. The coatings are preferably formed from solutions of halides of the metals in polar organic solvents such as methanol. The invention prolongs the life of lamps provided with the protective coating and enable such resistant and possibly cheaper materials to be employed for certain lamp components.