The General Equation of the High Pressure Mercury Porosimetry

Abstract

On the basis of the Gibbs condition of the thermodynamic equilibrium of a heterogeneous system in the field of force, a general expression is derived for the dependence of the pressure p' of the intruded liquid mercury as a function of the equivalent pore radius r. For pore radii greater than 30 nm, this equation goes over into the well known Washburn equation. For pores with r smaller than 2.5 nm sizeable deviations from the Washburn relation occur. It is shown that supermicropores (r from 0.8 to 1.4 nm), communicating with the system of meso and macropores, are filled by mercury at the same pressures p l at which the filling of mesopores (r from 2 to 10 nm) takes place.