Incandescent lamp having an illuminant that contains a high-temperature resistant metal compound

An incandescent lamp having an illuminant which contains a high-temperature resistant metal compound (7) and having electrodes (10) which hold the illuminant (7), the illuminant being introduced vacuum-tightly together with a filling in a bulb (2), the material of the illuminant comprising a metal or a metal compound, in particular a metal carbide, whose melting point lies close to the melting point of tungsten, preferably at least at 3000° C. and particularly preferably above that of tungsten, characterized in that the illuminant contains a material which becomes depleted of at least one chemical element owing to chemical decomposition and/or evaporation during operation, and in that a source and sink for this element are fitted in the bulb, the source delivering the element of which the illuminant is depleted and the element which the illuminant emits progressively during the lifetime being deposited on the sink, so that overall there is a continuous flux of the described element from the source to the sink, the concentration of the relevant element being essentially steady at any position in the lamp, apart from startup processes, the illuminant in steady-state operation being in equilibrium with the partial atmosphere of the element constantly transported past it, imposed from the outside by the interaction of the source and sink, so that the illuminant is prevented from being depleted of the element in question.