Crystal growth kinetics in BaOAl2O32SiO2 and SrOAl2O32SiO2 glasses

摘要: Crystallization kinetics of BaOAl2O32Si02 (BAS) and SrOAl2O32SiO2 (SAS) glasses in bulk powderforms have been studied by non-isothermal differential scanning calorimetry (DSC). The crystal growth activation energies were evaluated to be 473 451 kJ mol−1 for samples 560 534 powder specimens BAS SAS glasses, respectively. Development crystalline phases on thermal treatments at various temperatures has followed X-ray diffraction. Powder crystallized lower than the crystallization temperature was glass BAS. both appeared surface nucleated. high phase hexacelsian, MAl2Si2O8 (M = Ba or Sr), first nucleating preferentially surface. Also, monoclinic celsian does not nucleate directly glass, but is formed higher from transformation metastable hexagonal phase. In occurred rapidly after 1 h 1100 °C. contrast, this sluggish difficult did go completion even 10 heat treatment 1400 morphologies observed optical microscopy. Some physical properties two are also reported.