Nucleation efficiency in lithia-alumina-silica glasses

Abstract

The efficiency of TiO₂ as a nucleating agent in the Li₂O—Al₂O₃—SiO₂ system is explored over a wide composition range. Sharp changes in crystal growth rate, which strongly influence nucleation rate, are observed near the Li₂O·Al₂O₃—SiO₂ composition line and are ascribed to changes in fluidity of the glass at the crystal growth front caused by rejection of lithia-rich material by the growing crystals. A mechanism for triggered nucleation at the growth front is advanced to explain a discrepancy between crystal growth rate and final particle size. The general implications of the results are briefly discussed.