Crystallization behavior and IR structure of yttrium aluminosilicate glasses

The crystallization of four Y2O3-Al2O3-SiO2 (YAS) glasses were investigated to prepare YAS glass ceramics precipitated singly/mainly Y2Si2O7 or Y4.67(SiO4)3O apatite, and to explore the crystallization difference between the stoichiometric parent glass (SPG) and non-stoichiometric parent glass (NSPG). The DSC results revealed that glass locating at the higher liquidus surface temperature has lower crystallization peak temperature, which indicating that the corresponding glass has higher crystallization potential to crystallize easily. Crystallization of the NSPG samples is along surface and caused by phase separation, while SPG sample is the surface crystallization at the first exothermic peak temperature and overall crystallization at the second exothermic peak temperature. Glass ceramics only containing y-Y2Si2O7 or Y4.67(SiO4)3O apatite are obtained successfully, and which are illustrated by fitting FTIR spectra. These results can provide technical guide for controlling the crystallization process and the types of precipitated crystals in YAS glass for different application potentials.