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Oxidation roasting of molybdenite powder was carried out to study the effect of temperature and oxygen concentration on the oxidation rate. The results obtained in these experiments are as follows; 1) According to thermogravimetric analysis, the oxidation of 270/325 mesh molybdenite begins at about 300℃ and the rate of oxidation increases with increasing temperature especially above 500℃. 2) The oxidation rate of molybdenite increases with the increasing oxygen concentration and reaction temperature. But above 550℃ molybdenum is lost by the vaporization of MoO₃. 3) The overall oxidation rate of molybdenite at the temperature range of 445-545℃ predominantly controlled by diffusion rate of oxygen through the MoO₃layer, and the apparant activation energy of the process is evaluated as 16㎉/mole.

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Under constant peak stress conditions cyclic creep behavior of pure aluminum is quantitatively investigated in the temperature range of 333K-548K (0.36-0.59 Tm, where Tm is melting temperature in the absolute scale). Cyclic creep acceleration is found to occur up to a temperature of about 0.5 Tm. The phenomenon is more significant with increasing stress at a given temperature. The measured activation energy for cyclic creep deformation, Q_(cy), is found to be lower than that of static creep, Q_(st). It seems that this difference can be interpreted by using an effective diffusion coefficient, D_(eff), Which includes an excess vacancy term for cyclic creep.

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In order to investigate the effect of zinc on the structure and mechanical properties of the silver base dental amalgam, the experiment was performed by setting the zinc content from 0 to 8% in Ag-Sn system alloy for dental application. From this experiment following results were obtained ; 1. γphase in the pre-alloy structure decreased as zinc content increased, whereas free Sn and Ag-Zn phase increased as zinc content increased. 2. Unreacted γphase in the amalgam structure decreased as zinc content increased, whereas γ₂phase increased as zinc content increased. 3. Hardness of γphase in the pre-alloy increased as zinc content increased. 4. Hardness and compressive strength of amalgam alloy containning zinc up to 3.7% increased as znic content increased, and then dereased with much more zinc content. 5. Hardness and compressive strength of amalgam alloy increased with aging.

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Roulette theory has been applied to liquid metals to calculate the thermodynamic properties of Na, Ag, Cu, K, Au, Pb, Cs, Hg and Rb. The partition function was formulated under the assumption that molecules of the liquid state consist of Einstein molecules, Lennard-Jones and Devonshire molecules, and van der Waals molecules. Although a liquid metal is known a severe test for any liquid theory to lead to large differences between observed and. calculated values for thermodynamic properties, the agreement is quite good for molar volume and vapor pressures for many liquid metals. The results concerning Cv, Cp, and β are not in as good agreement as might be hoped, but it is clear that the theory is correct in principle even for liquid metals.

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