Porosimetry

Mercury porosimetry is a method of analysis to determine various quantifiable aspects of a porous material, such as pore size distribution, the total pore volume, the inner surface, the bulk density and the absolute density.

Implementation

The technique involves the penetration of a non-wetting liquid such as mercury, high pressure in a material using a porosimeter. The pore size is determined as a function of the external pressure, which is necessary to push the fluid in a pore to the surface tension of the liquid.

For cylindrical pores, the so-called the Washburn equation:

The technique is carried out usually under vacuum. The contact angle of mercury with most solids is between 135 ° and 142 °. The surface tension of mercury at 20 ° C under vacuum is 480 mN / m. Substituting we get:

With increasing pressure also increases the cumulative pore volume. From the cumulative pore volume, the average pore size can be determined. A derivation of the cumulative pore volume distribution results in a differential pore radius distribution.

Application Examples

Means of mercury was bone Bronze Age skeletons from Cladh Hallan degree of degradation was determined and found that the deceased were artificially preserved after your death by endogenous bacteria from the digestive tract.