長残光性透明ガラスセラミックスの作製における超音波前処理効果

The effects of ultrasonic surface treatment (UST) on the crystallization behavior and optical emission properties were investigated for the transparent glass-ceramics prepared from calcium aluminosilicate glasses co-doped with Eu(2+), Nd(3+). The glass-ceramics A were prepared by sintering a glass 45CaO・45Al(2)O(3)・10SiO(2) (mol%) containing 0.5Eu(2)O(3)+1Nd(2)O(3) under a 2% H(2)+98% Ar reducing atmosphere. In the glass-ceramics A, three crystalline phases, CaAl(2)O(4) (CA), CaAl(4)O(7) (CA2) and Ca(2)Al(2)SiO(7) (CAS) were commonly confirmed by X-ray diffraction. No drastic change in the amount of the precipitated crystalline phases was observed even in the case using UST of CA powders. It was suggested that the optical emission properties of the glass-ceramics A was responsible for the CA2 crystals. The glass-ceramics B were also prepared from a 51CaO・42Al(2)O(3)・7SiO(2) glass. The CA crystals were separately precipitated in the glass-ceramics B. In particular, a large amount of CA was successfully produced by stirring the UST suspension to prevent the sedimentation of the UST particles. The glass-ceramic B so-prepared showed strong photoluminescence but weak phosphorescence compared with other glass-ceramics B, indicating that the photoluminescence and phosphorescence were originated in different electron-trapping levels. The amount of the trap levels associated with the long lasting phosphorescence, such as oxygen vacancies, was probably small in the glass-ceramic B prepared with the stirring UST.