The typical
methods to measure the pore size distribution of power and materials are the
gas adsorption and mercury porosimetry.
The pore size distribution from the gas adsorption method is commonly analyzed from the
nitrogen or Ar adsorption isotherm at their boiling temperature, and it is
possible to evaluate the pore size from the molecular size to a few hundred nm.
The realistic largest detectable pore size is just over 100nm due to the
restriction from the pressure sensor accuracy and temperature stability of
coolant. Mercury porosimetry calculates the pore size distribution by
pressurizing mercury, which is non-wetting, and measure the corresponding
intrusion amount. By this method, it is possible to detect the pore size from a
few nm to 1000μm within a short period of time. For the pore size measurement
below 10nm, it requires over 140MPa of pressure for the intrusion of mercury,
so it is necessary to make sure that the material has the strength to withstand
the pressure. Also, by this method, it evaluates the pore size of inkbottle
neck (the smallest diameter of the pore) from the principle. The realistic
measurement range is from a few 10 nm.
Recently, there
are bubble point method and gas permeation method to measure the through pore
size of filters and separation membranes.
Determination of pore size distribution
V-Sorb 2800 Instroduction
