Liquid Immersion-Polarized Light Microscopy as a Powerful Tool in the Research of Ceramic Processing

This paper presents a novel characterization method which can reveal the presence of large crystalline particles of very low concentration and particle orientation in optically anisotropic granules, i.e. alumina. It involves an adequate immersion liquid which makes granules transparent and subsequent polarized optical microscopic examination. Large alumina particles are easily detected by this method: They are clearly visible under the crossed polarized light mode. Particle orientation in the matrix particles was also noted: Dark cross pattern appeared on the granules, showing the orientation of particle along the tangential direction of granules. The significance of these features for ceramic processing was discussed.