Method for determining diffusion and/or transfer coefficients of a material

摘要

The invention relates to a method for the determination of diffusion coefficients and/or exchange coefficient of a material having electronic and ionic conductivity. The material is permeable to at least one gas. It is the object of the invention to provide a cost-effective, accurate method for the determination of the diffusion coefficient and of the surface exchange coefficient which can be carried out in a short time and can thus be used for a screening of materials, in particular for application in the field of permeation membranes. The procedure is followed in accordance with the invention such that a sample of the material is arranged in a measurement chamber and has an electric current passed through it for a determination of the electric resistance. In this respect, a gas mixture in which the respective gas is contained is conducted through the measurement chamber as a gas flow and the partial pressure of the respective gas in the gas mixture is changed periodically at regular intervals. The change in the electric resistance of the sample is measured and a diffusion coefficient and/or exchange coefficient of the material can be determined for the respective gas from the determined change in the electric resistance.