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 μm/s. The c axes of most crystals were oriented in the direction perpendicular to the surface of the Al₂O₃ rod as illustrated by scanning electron microscope and pole figures. The degree of crystal orientation increased with increasing crystallization temperature. At higher temperatures (e.g., at 892 °C), even single-crystal-like dendrites were formed.