High-Temperature Protective Coatings of Refractory Melts (Mo, W, Nb, Ta) and Alloys Based on Them,

As a result of the investigations at the present time in the scope of the development of high-temperature protective coatings for W, Ta, Mo and Nb determinable successes have been achieved. The complex silicide coatings insure the reliable performance of these materials up to temperatures of 1300-1800C however, their service life thus far is short and at high above 1400C temperatures is limited to a dozen hours. For the protection of the big four metals at temperatures above 2000C the high-enthalpic oxides of ThO2, HfO2, ZrO2 and cermets on their bases are promising. Investigations are necessary on the thermodynamic properties of the substances which are included in the composition of protective coatings oxides, silicides, etc. at temperatures on the order of 1500-2000C and higher.