セラミックスのインテリジェントナノ焼結

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This article describes a study of intelligent nanosintering, as the author here use this term, by which one can provide a platform for the bulk nanocrystalline synthesis using multi-variable controled thermo-mechanical processing equipped with pulse electric current and microwave heating. Emphasis is firstly placed on the set-up of the phenomenology of electric field assisted densification during heating of the amorphous ceramic powder by varying manipulating variables of electric current, compact height and millimeter wave radiation power. In the case of amorphous and/or nanocrystalline ZrO2-Al2O3, the rate of densification enhanced under electric field (E) is expressed on the basis of an Arrhenius-type equation of Newtonian viscous flow, ηp = ηp0(E) esp{Q(E)/kT}, having a decreased value of the apparent activation energy (H). Then, within the framework of sintering route map up to full-density, the optimal condition for in process nonequilibrium structure control densification is provided with the reference to constitutive equations for densification during viscous flow and/or superplastic flow and the master sintering curve for densification accompanying grain growth. Moreover, it is evidenced that a variety of nanosintering techniques makes it possible to synthesize fully densified samples of amorphous B4C, nanocrystalline cubic and tetragonal (ZrO2-3mol%Y2O3)80(Al2O3)20 using nanomechanochemically synthesized amorphous powders.
2010-12-15