Patent ID: 7955715

Claim:
A component for use at a high working temperature in a crucible drawing method for quartz glass, said component comprising: a base body comprising a wall of tungsten or a tungsten-containing high temperature-resistant alloy; said wall being covered at least in part with a protective layer containing a coating metal selected from the group consisting of iridium, rhenium, osmium and ruthenium; wherein the protective layer is of a layer material containing tungsten and the coating metal; the coating metal being in an amount that exceeds a limit amount thereof of a coating metal-rich phase boundary of a solid mixture phase of tungsten and the coating metal with the solid mixture phase being thermodynamically stable at the working temperature, by not more than 25 at. % based on the total amount of tungsten and the coating metal in the layer material; and wherein the layer material contains iridium as the coating metal, and the iridium amount based on the total amount of tungsten and iridium in the layer material is not more than 50 at. %, and at least 5 at. %.