Porosimetry by Nitrogen Adsorption
Nitrogen Porosimetry determines pore information by condensing nitrogen in the pores of a material and then calculating the pore volumes from the quantities of gas required to fill the pores. Analyses are usually performed in conjunction with surface area analysis. For porosimetry analyses, the instrument does not stop with the first adsorbed layer of gas that is needed for surface area determination. Instead, the instrument continues to fill the sample with gas until bulk condensation begins.
Nitrogen adsorption testing includes: Multi Point Suface Area, Total Pore volume, Pore Size Distribution, Average Pore Diameter, and Micropore Volume
A typical report consists of an adsorb/desorb isotherm, tabular data, and graphs illustrating pore values.
Sample requirements for testing: 10 grams of sample minimum. Material shall fit into an 8mm diameter sample tube for testing.
Porosimetry by Mercury Intrusion/Extrusion
The Mercury Porosimetry measures pore diameters in the 0.003 um - 360 um range. This method of structure analysis is faster than nitrogen porosimetry. Since this analysis requires pressures at a maximum of 60,000 psi and uses mercury, not all materials can be analyzed by this method. With mercury porosimetry, pore information is obtained by forcing liquid mercury into pores by increasing the external pressure. As the pressure is incrementally increased, the amount of mercury required to fill the pores is recorded. This information, as well as information concerning the contact angle, is used to calculate the pore structures using the Washburn equation.
Pore area and pore volume graphs, bulk density, skeletal density, and porosity values are reported. Additionally, tabular data and cumulative data are included.
Mercury Porosimetry testing is performed as Intrusion only or Intrusion and Extrusion.
Sample requirements for testing:
10 grams total, if possible. Material shall fit into a 0.5” diameter by 1” length sample tube for testing.