- Mercury porosimeter has a very high sensitivity to measure the volume of mercury entering the pores even to values as low as 0.1 µL.
- This method is used to measure pore sizes in the range of 0.003 to 1100 microns.
- The volume of pores at the corresponding sizes are measured based on volume of intrusion of mercury into the sample and total pore area can also be calculated.
Mercury porosimeter is used to measure pore size distribution and porosity of porous materials by forcing mercury into the sample under external pressure, as it is a non-wetting liquid and so it cannot naturally penetrate the pores by capillary action. The pressure needed to force mercury into the sample is inversely proportional to the pore size. Under pressure, the mercury leaves the penetrometer stem which is an electrical capacitance dilatometer and enters the sample. The stem is coated with a metal plating and this acts as a coaxial capacitor along with mercury inside it. As the pressure changes, the volume of mercury entering the pores in the sample is measured by reduction in the capacitance.