Mercury porosimetry is a very valuable technique, especially because it covers an extremely wide pore size range (Fig. 10). It certainly has its limitations, but carefully set experimental process conditions and a sensible data analysis provide valuable information about the sample. It is recommended that standard procedures be followed, for example, ASTM

standards D 4284 (Ref 50) and C 493 (Ref 51). A good overview on mercury porosimetry with respect to different materials and other aspects of the technique is given in several articles in Ref 52.

It is recommended that close attention be paid to a correct and meaningful data presentation. The differential plot of the pore size distribution can easily lead to a misinterpretation of the results if the graph is calculated with the "wrong" axis:

• A A pore volume/Alog (pore size) should be used to represent the differential distribution equivalent to the cumulative distribution when using a logarithmic axis for pore size.

• Using ¿pore volume/A pore size leads to an overestimation of small pores.

• Plotting the pore volume versus applied pressure on a linear pressure axis allows determination and recognition of compressibility effects of the sample or the mercury.

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