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| THE OXIDATION OF MOLYBDENUM AT INTERMEDIATE TEMPERATURES |
| LI HSUN;CHENG YI-PING;YIN YAO-TEH Institute of Metal Research; Academia Sinica |
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Cite this article:
LI HSUN;CHENG YI-PING;YIN YAO-TEH Institute of Metal Research; Academia Sinica. THE OXIDATION OF MOLYBDENUM AT INTERMEDIATE TEMPERATURES. Acta Metall Sin, 1965, 8(2): 221-283.
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Abstract An investigation on the oxidation of molybdenum at 350-500℃ was carried outwithin the range of 1-76 mm Hg oxygen pressure. It is shown that MoO_2 was formedfrom the very beginning directly on the molybdenum surface at all temperatures. MoO_3came to appearance later when the first-formed MoO_2 layer had attained a certain thick-ness which seems to vary with temperature and oxygen pressure. The growth of MoO_2 on molybdenum was found to obey a parabolic rate law. Itwas continued at a later stage along with the growth of MoO_3 which was confined tothe outer layer of the surface oxide. The presence of MoO_3 increased the over-all rateof oxidation somewhat, but the growth law, being parabolic, was apparently unaltered. The grain-size of MoO_3 as observed at the outer surface increased with the increasedtime of oxidation. Coarse grains of MoO_3 were prone to detachment from the oxidizedsurface, thus suggesting a kind of loosening grain-structure which may have connectionswith the departure from the parabolic towards a linear rate law of oxidation at 450℃. The rate of oxidation of molybdenum at 450℃ was found to vary with the oxygenpressure in such a way that K_P∝Po_2~(2/3). In view of this, it is suggested that theconcentration of oxygen molecules in the adsorbed surface layer may play a controllingrole upon the oxidation of molybdenum.
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Received: 18 February 1965
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[1] Lustman, B.: Metal Progr., 1950, 57, 629．
[2] Nachtigall, E.: Z. Metallk., 1952, 43, 23．
[3] #12
[4] Simnad, M., Spilners, A.: Trans. AIME, 1955, 203, 1011．
[5] Semmel, J. W.: High Temperature Materials Conference, AIME, Held in Cleveland, Ohio. (Wiley, 1959) , p. 510．
[6] Jones, E. S., Mosher, C. J. F., Speiser, R. et al.: Corrosion, 1958, 14, 2t.
[7] Gulbransen, E. A., Andrew, K. F., Brassart, F. A.: J. Electrochem. Soc., 1963, 112, 952．
[8] Gulbransen, E. A., Wysong, W. S.: Trans. AIME 1948, 175, 628．
[9] Peterson, R. C., Fassell, W. M.: Technol. Rept. Univ. Utah, 1954, (9) .
[10] Gorbounova, K. M., Arslambekov, V. A.: 6~e Reunion De La Societe De Chimie Physique, 1956, Paris.
[11] #12
[12] Hickman, J. W., Gulbransen, E. A.: Trans. AIME, 1947, 171, 371．
[13] Engell, H. J., Hauffe, K., Ilschner, B.: Z. Elektrochem., 1954, 58, 478．
[14] #12
[15] Bosworth, R. C.: Trans. Faraday Soc., 1932, 28, 896, 903．
[16] Gyani, B. P.: J. Phys. Chem., 1945, 49, 442．
[17] Gyani, B. P.: J. Phys. Chem., 1949, 53, 1091．
[18] Langmuir, I.: J. Am. Chem. Soc., 1916, 38, 2221 |
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