Conclusions
At any given sintering temperature the relative rate of densificaron of compacts of porosities 29–44% from reduced and atomized tungsten powders of particle sizes 1.5–5μm is determined by their capillary pressure, the character of this dependence being close to linear. Densification during sintering is a threshold process, i.e., porous skeletons behave during sintering like Bingham solids. For each sintering temperature there exists a critical pore size above which the rate of densification sharply changes, approaching zero. Assessments of coefficients of Bingham viscosity have shown that at 1600 and 1900°C they are linear functions of sintering time. The energy of activation for the densification of the powders investigated during sintering in the range 1600–2000°C is equal to the energy of activation for grain-boundary self-diffusion in tungsten and amounts to 90 ± 5 kcal/mole.
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Translated from Poroshkovaya Metallurgiya, No. 10(262), pp. 27–32, October, 1984.
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Get'man, O.I., Rakitin, S.P. & Skorokhod, V.V. Rheological and thermal activation analyses of the sintering kinetics of tungsten powders. Powder Metall Met Ceram 23, 764–768 (1984). https://doi.org/10.1007/BF00792139
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DOI: https://doi.org/10.1007/BF00792139