Oriented calcium metaphosphate glass-ceramics

Highly oriented calcium metaphosphate glass-ceramics were obtained directly from the corresponding melt. On the interface between the Ca(PO3)(2) melt and an Al2O3 rod, the nucleation could easily be induced. The dependence of the crystal growth rate on the crystallization temperature was determined. The crystal growth rates observed were up to 71 mu m/s. The c axes of most crystals were oriented in the direction perpendicular to the surface of th e Al2O3 rod as illustrated by scanning electron microscope and pole figures . The degree of crystal orientation increased with increasing crystallizati on temperature. At higher temperatures (e.g., at 892 degrees C), even singl e-crystal-like dendrites were formed.