Toshiaki Yoneoka1, Michio Yamawaki2 and Masayoshi Kanno1
1Faculty of Engineering, The University of Tokyo, Tokyo
Oxidation of pure vanadium has been investigated at temperatures of 723∼903 K and oxygen pressures of 1.33×103∼1.33×104 Pa by means of a thermo-electrobalance, an X-ray diffractometer, a Knoop hardness tester as well as metallographic techniques. The oxidation proceeded according to a parabolic rate law. The obtained parabolic rate constans scarcely exhibited pressure dependence. The activation energy for parabolic oxidation process was about 180 kJ/mol. The oxide scale on most specimens was composed of three layers of V2O5, V6O13 and VO2. These results were compared with those of the preceding study performed at lower oxygen pressures of 0.133∼133 Pa.
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