Electron microscopy of some wollastonite based porcelains

Electron microscopy studies were made on five calcium porcelains whose starting batches consisted of kaolinite clay, wollastonite and a lead borate frit. Transmission and scanning electron microscopy, as well as X-ray energy dispersive microanalysis were used. The mineral composition of the resulting porcelains was found to be primarily anorthite, wollastonite and quartz. Anorthite, the most abundant crystal phase, was found to be present in a wide range of sizes and shapes, suggesting that it is formed in these porcelains by more than one mechanism. This may be related to the presence of a vitreous phase of special characteristics. It seems possible to direct the growth of the anorthite crystals, not only towards different sizes but also towards specific shapes for the purpose of inducing convenient microstructures.