Pore structure characterization by mercury porosimetry

This chapter describes how mercury porosimetry is conducted by first preparing a sample of a size dependent on the material porosity and with pore volume measurable by the equipment. The sample is placed in a holder called a penetrometer, evacuated, and then immersed in mercury at a low pressure. Increasing pressures are applied on the mercury and corresponding volumes of intruded mercury are determined. Surface area estimates, comparison of area estimates, and validity of the BET surface area estimates are discussed. Mercury porosimetry can distinguish between materials with a narrow pore size distribution, such as a filter, or those with broad distributions, often as much as 3 to 4 orders of magnitude in pore size, like refractories