Effects of Nb-Alloying on High-Temperature Oxidation of MoSi2 |
| A.A. Sharif
California State University Los Angeles, Department of Mechanical Engineering, 5151 State University Dr., Los Angeles, CA 90032-8153, USA |
| Full Text PDF |
| The effects of alloying with 0.5, 1.0, and 2.0 at.% Nb on oxidation resistance of MoSi2 are investigated at temperature range of 1400°C-1700°C. Rapid formation of a stable protective layer of silica resulted in a parabolic oxidation rate. The oxide layer thickness and the sample weight increased with increasing oxidation time. Impurities accelerated oxidation rate of MoSi2 only slightly, however, did not affect the rate controlling mechanism for oxidation. There was no correlation between oxidation rate and the amount of impurity. The values of activation energies for oxidation of pure MoSi2 and Nb-alloyed samples were similar to activation energy for diffusion of O2 through silica. Diffusion of O2 through the oxide scale remained the rate controlling mechanism with or without Nb impurity. |
DOI: 10.12693/APhysPolA.125.563 PACS numbers: 64.75.Lm |