Reduction of pt and rh evaporation losses at high temperatures by using a barrier layer

Parts made of platinum or a Pt alloy, the outer surface of which comes in contact with an oxidizing atmosphere during operation and is covered with an open-cell ceramic or quartz layer, the pores containing a material that melts at the operating temperature as an infiltration material, are protected against loss caused by evaporation when used in an oxidizing atmosphere at temperatures exceeding 1200 DEG C. A method for reducing the evaporation rate out of platinum and Pt alloys in an oxidizing atmosphere comprises the steps of A. applying an open-cell quartz or ceramic layer, B. infiltrating said quartz or ceramic layer with a material melting at a lower temperature than the ceramic material such that pore spaces of the open-cell ceramic layer are partially or entirely filled by the infiltration material, C. use at temperatures exceeding 1200 DEG C.