| Description |
Pressed cylinders and powder molybdenum disulfide samples were oxidized under a range of temperatures from 492°C to 670°C and oxygen partial pressures between 0.003 and 0.860 Atm. By varying these parameters, different physical behaviors were observed on the oxidized samples. According to this, five regions were differentiated in an oxygen partial pressure-temperature diagram. Each region was analyzed and the samples behavior qualitatively explained. The only region where topochemical reaction was accomplished was used for quantitative kinetic study. The oxidation rates were followed by the samples weight change The data in this region was corrected for the surface area change of the reacting front. Under fixed conditions of temperature and oxygen partial pressure, the oxidation rate per unit surface area of residual molybdenum disulfide was linear and directly proportional to the oxygen partial pressure to the first power. The linear oxidation was explained in terms of oxygen adsorption as molecules, which represents controlling step. the rate The activation energy for the oxidation reaction was found to be 42. 4 ± l kcal/mole e The production of molybdenum dioxide was explained in terms of the direct oxidation of molybdenum disulfide. |
