Conclusions
At temperatures of up to 1400°C hot pressing under isothermal conditions enables higher (by ∼5%) densities to be obtained in compacts fromγ-Al2O3 powders than in compacts fromα-Al2O3 powders. With rise in temperature the difference between the densification rates ofα- and γ-Al2O3 powders diminshes. The difference in density betweenα- andγ-Al2O3 compacts is preserved up to a temperature of 1600°C in hot pressing at a constant heating rate of 5 deg C/min. In the temperature range 1300–18QO°C the energy of activation for hot pressing Al2O3 varies from 50 to 75 kcal/g· form. Estimated values of viscosity and effective diffusion coefficient are in accord with values determined in creep and sintering experiments.
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Translated from Poroshkovaya Metallurgiya, No. 9(165), pp. 76–80, September, 1976.
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Spivak, I.I., Rystsov, V.N. Role of polymorphic transformation in the hot pressing of alumina. Powder Metall Met Ceram 15, 720–723 (1976). https://doi.org/10.1007/BF01157845
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DOI: https://doi.org/10.1007/BF01157845