Crystallisation Of Celsian (Baal2Si2O8) Glass

The fabrication and crystallisation of stoichiometric and near-stoichiometric celsian, BaAl2Si2O8 (BAS), glass made via melt and sol-gel routes is reviewed. After considering celsian polymorphism and methods of stabilising monoclinic celsian, some new experimental results are presented which show that melt glass crystallises predominantly via surface nucleation, but sol-gel glass via volume nucleation.