The Relation of Viscosity, Nuclei Formation, and Crystal Growth in Titania-Opacified Enamel

This investigation shows that there is a relationship between viscosity, number of nuclei, and crystal growth during the firing of titania-opacified enamels. This agrees with a similar relationship which Tammann found in his experiments with organic glasses. The history of the development of the size, shape, and relative number of particles per unit area of titanium dioxide crystals was traced from 650° to 1300°C. As the temperature increased from 700° to 1100°C., the color of the specimens viewed under reflected light changed from light blue to white and then to cream-white. The methods used in this investigation were the measurement of viscosity, X-ray analysis, differential thermal analysis, and the study by light microscopy and electron microscopy of very thin heat-treated films which had been produced by blowing bubbles from high-temperature melts.