Abstract: Disclosed herein is the preparation of thin films of tungsten, molybdenum, rhenium or osmium on a high-temperature resistant substrate by thermal evaporation in a high vacuum, wherein the oxides of these high-temperature-resistant metals are evaporated simultaneously with a reduction metal in a manner such that the oxide molecules and the metal atoms or molecules impinge together on the surface of the substrate heated to a predetermined temperature and react with each other there chemically, so that the high-temperature-resistant metal oxides are reduced and the reduction metals are oxidized. In this process, the high-temperature-resistant metal is deposited on the surface of the substrate, and the oxides of the reduction metals evaporate, either completely or partially, and are pumped off.