CONTRIBUTION OF THE PRESSURE VARIATION OF THE POROSITY TO THE ACTIVATION VOLUME EVALUATION FROM IONIC-CONDUCTIVITY MEASUREMENTS UNDER PRESSURE

In the present paper the pressure variation of the porosity is express ed in terms of the elastic properties of the porous solid which consis ts of a one-phase solid framework and the pore space that is assumed t o be empty. The equation which describes the pressure variation of the conductance of a porous ionic material is modified to include the por osity modification upon pressure. The change of the porosity induced b y the pressure contributes to the value of the activation volume which is inferred from conductance under pressure experiments. Additionally , we predict that the porosity change significantly accounts for the s econd order pressure derivative of the conductance and consequently co ntributes to the estimation of the compressibility of the activation v olume. (C) 1997 Elsevier Science Ltd. All rights reserved.