Mercury intrusion curve high-pore-volume silica

Figure 2. Mercury intrusion curve of a typical high-pore-volume silica used in...

In a previous study [5], we showed that some materials, in particular the low density silica xerogels, exhibit a remarkable behavior when submitted to mercury porosimetry. At low pressure, the volume variation observed is entirely due to a crushing mechanism, generally irreversible with sometimes a weak elastic component. At high pressure, these xerogels are invaded by mercury which intrudes the pore network. The transition fi om the crushing mechanism to intrusion is sudden at a pressure Pi, characteristic of the material. This particular point can be easily located on the curve of cumulative volume versus logarithm of pressure by... 

High dispersive precipitated silica submitted to an increasing pressure in a mercury porosimeter shows successively a collapse mechanism of porous texture followed by a mechanism of mercury intrusion in the part of pore network which has resisted to the collapse. Such a behavior has been previously observed on low density xerogels and on some carbon black. Both mechanisms can be clearly distinguished by a sharp variation of slope of cumulative pore volume curve versus pressure. 

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