| The rate of thermal dissociation of calcium hydride was measured under argon atmosphere using a thermogravimetric technique. The weight less curve were obtained for various conditions in temperature range of 790 C to 840 C, and the temperature dependence of dissociation rate was also determined. As variables, Hydrogen partial pressure, total flow rate and the shape of the sample holder were involved, their effects on the dissociation rate were discussed. The reaction mechanism was estimated comparing the experimental results with various reaction models assuming chemical reaction control at the interface, diffusion control in the products layer or gas film diffusion at surface, in each case the rate parameters for mass transfer was calculated. From the experimental results, the reaction was shown to be mainly controlled by surface gas film diffusion. |
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