IMPROVED OXIDATION RESISTANCE OF MOLYBDENUM BY ALLOYING WITH RARE EARTH AND OTHER SELECTED METALS
Abstract
Selective oxidation experiments were carried out at temperatures ranging from 1000 to 1540 C on binary Mo alloys containing 0.026 at-% Yt and 0.056 at-% Hf, respectively, with the object of forming protective coatings of Y2O3 and HfO2. Yt and Hf were selectively oxidized in an H atmosphere. The oxidation rates were parabolic and were achieved by a mechanism of internal oxidation in all experiments performed. This mechanism indicated that the oxygen flux into the alloy exceeded the outward flux of the alloying element to the alloy-air interface. To achieve a protective coating on the alloy surface these rates of flux should be equal. The parabolic rate constants obtained and estimated diffusion coefficients indicated that the outward flux of Yt and of Hf should have been sufficient to achieve a protective outer coating. These results show that higher alloying contents of Yt and Hf, or higher temperatures may well yield the results sought. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 29, 1962
- Accession Number
- AD0277355
Entities
Organizations
- Colorado School of Mines