High‐Strength Ca(PO ₃ ) ₂ Glass‐Ceramics Prepared by Unidirectional Crystallization

Abstract

New CaO‐P 2 P 5 glass ceramics were prepared by crystallizing glass rods or plates unidirectionally in a temperature‐gradient furnace. The unidirectionally crystallized glass showed extremely high bending strength (∼500 to 600 MN/m 2 ) even when subjected to a severe abrasion treatment with Sic paper. Scanning electron microscopy of fracture surjaces revealed a typical fiber‐reinforced‐composite structure. Crystalline phases and crystallographic directions were checked by X‐ray diflraction. The fracture mechanism is discussed in terms of microstructure.