INVESTIGATION OF PORE STRUCTURE BY A NON-STEADY-STATE GAS-DIFFUSION TECHNIQUE

Experimental details are given of technique for investigating the internal geometry of a porous material, with particular reference to dead-end pores, especially those of the ″ink bottle″ geometry (restricted-access pores). The pores of the sample are initially filled with a tracer gas (e. g. methane), and the transient diffusion of the tracer into a carrier gas (e. g. nitrogen) is measured (e. g. by flame ionization detection). Typical results are given, which indicate the potential of the method for studying a key aspect of the pore structure of technologically important materials. Current approaches to the theoretical modeling of the relevant structures are also indicated.