Microscopic study of pore structure

Abstract

Abstract The relative merits of optical microscopic methods in study of the pore structure of some ceramic materials (mainly graphite) are discussed on the basis of comparison of the results of this method with those from other current methods, such as apparent and true density measurements and mercury high-pressure porosimetry. A modified microscopic method has been developed in which direct replicas of polished sections are examined under an interference-polarisation microscope and indirect replicas under the electron microscope. In this method the main drawbacks of the microscopic method are suppressed to a great degree. In cases of materials containing pores of an irregular shape and of wide size distribution, such as the graphite studied, the optical microscopic method has many advantages in comparison with other methods when the random and systematic errors of this method are properly recognised and suppressed. The cumbersome evaluation of the microscopic images and/or photomicrographs may sometimes be avoided by using the image analysing computer but the latter proved to be of a lower accuracy in the case of the graphite studied.