An approach to new glasses through phase separation

The application of liquid-liquid phase separation to the preparation of new glasses has been demonstrated. The in situ observation of phase separation has been made on some berate liquids at 1-g (g = gravitational field at Earth's surface) and under microgravity circumstances (drop tests) to estimate rates of phase separation. The liquid-liquid phase separation of barium berate liquids resulted in the precipitation of droplets of several tens of a micrometer in diameter, which was assumed to be applicable for the preparation of glass spheres, lens array, etc. The addition of rare earth oxide to the systems resulted in enriching the rare earth content of the precipitated droplets, indicating that the composition of the droplets would be modified by adding another oxide to melts. The microgravity circumstances decreased the phase separation rates and were found to be favorable for the preparation of glass spheres. (C) 1999 Published by Elsevier Science B.V. All rights reserved.