Lithium aluminosilicate (LAS) glass-ceramics: a review of recent progress

ABSTRACT The lithium aluminosilicate system (LAS) is being explored for almost seven decades due to its anomalous and attractive properties (especially low/negative thermal expansion and fast ion conduction) and its commercial significance in consumer as well as strategic sectors. This review introduces current commercial applications of LAS systems, necessary background science, structural features of different LAS crystal systems, including their polymorphs and solid-solutions, and the origin of unusual properties. Significant emphasis is provided on processing transparent, nanocrystalline, low thermal expansion glass-ceramic (LEGC), the role of chemical constituents and additives, the effect of heat-treatment, and microstructural evolution while processing LEGC. Detailed discussions are provided on the following areas: LAS matrix composites, chemical strengthening of glass and glass-ceramic, low temperature co-fired ceramics (LTCC) and associated joining technologies (hydrolysis catalysis bonding, anodic bonding, brazing, etc.) that would further extend the application portfolio of LAS system.