Process for producing a coating on a refractory structural member

A process for producing a coating on a refractory structural member, comprising the steps of:

• applying a noble metal alloy to a refractory member as a coating material, the noble metal alloy containing a noble metal with a melting point greater than 1,400° C., the noble metal being at least one of platinum, iridium, rhodium, ruthenium and gold, the noble metal alloy being used in powder form to coat the refractory member, the noble metal alloy having a liquidus temperature TL of 900° C. to 1,400° C., the noble metal alloy containing noble metal in an amount of ≧84 to ≦99.5 wt. % and containing an oxidizable substance in an amount of ≧0.5 to ≦16 wt. %, the oxidizable substance including at least one of boron, phosphorus, antimony and arsenic;
• heating the refractory structural member and the coating at least once in an oxygen-containing atmosphere to a temperature T that is at least equal to the liquidus temperature TL of the noble metal alloy;
• oxidizing the oxidizable substance during the heating step so as to form an oxide that is at least partially vaporized;
• maintaining the temperature T until a proportion of oxidizable substance in the coating is <0.1 atomic percent;
• and subsequently cooling the coated refractory structural member.