Preparation of long-lasting transparent glass-ceramic phosphor

The preparation of The transparent glass-ceramics with long lasting phosphorescence (LLP) was triedby precipitation of crystals from glassy materials by各种实验方法glass-ceramics containing calcium aluminate crystals co-doped with Eu^<2+> and Nd^<3+> or akermanitestrontium magnesium silicate) type crystals co-doped with Eu^<2+> and Dy^<3+>. The glass in Thesystem 45CaO / 45 al_2_3 / 10 sio_2 (mol%) containing 0.5 eu_2_3 + 1nd_2_3 showed very weak LLP propertydue to glassy state even though Eu ions were effectively reduced to Eu^<2+> ion state by melting theglass with reducing agents like sugar or graphite. Therefore to keep a certain crystal state isnecessity to excellent LLP property. The effects of ultrasonic surface treatment on Thecrystallization behavior and optical emission properties were investigated for the transparentglass-ceramics prepared from calcium aluminosilicate glasses co-doped with Eu^<2+> and Nd^<3+>. Theglass-ceramics A wer…More e prepared by sintering a glass 45CaO / 45 al_2_3 / 10 sio_2 (mol%) containingo_2_3 + 1nd_2_3 under a 2% h_2 +98%Ar reducing atmosphere. In the glass-ceramics a，three crystalline phases, caal_2_4 (CA)，caal_4o_7 （CA2）和ca_2al_2 sio_7 (CAS) were commonly confirmed by X-ray diffraction. No drasticchange in the amount of the precipitated crystalline phases observed even in the case using USTCA powders. It was suggested that the optical emission properties of the glass-ceramics A wasresponsible for the CA2 crystals. the glass-ceramics B也可以预先从a51CaO / 42 al_2_3 / 7 sio_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 thesedimentation of the UST particles. the glass-ceramic B so-prepared showed strong photoluminescencebut weak phosphorescence compared with other glass-ceramics B，indicating that the photoluminescence and phosphorescence originated in differentelectron-trapping levels. The amount of The trap levels associated with The long lastingphosphorescence, such as oxygen vacancies，在glasses -ceramic B prepared with the stirring UST. When the glasses weremelted with reducing agent like sugar, partially crystallized under a reducing atmosphereglass-ceramics showed excellent LLP properties. The glass-ceramics with LLP precipitated akermanitetype crystals co-doped with Eu^<2+> and Dy^<3+> were also obtained by melting and crystallizingunder reducing conditions. Less

The preparation of the transparent glass-ceramics with long lasting phosphorescence (LLP) was tried by precipitation of crystals from glassy materials by means of various experimental methods. The glass-ceramics containing calcium aluminate crystals co-doped with Eu^<2+> and Nd^<3+> or akermanite (strontium magnesium silicate) type crystals co-doped with Eu^<2+> and Dy^<3+>. The glass in the system 45CaO・45Al_2O_3・10SiO_2 (mol%) containing 0.5Eu_2O_3+1Nd_2O_3 showed very weak LLP property due to glassy state even though Eu ions were effectively reduced to Eu^<2+> ion state by melting the glass with reducing agents like sugar or graphite. Therefore to keep a certain crystal state is necessity to excellent LLP property. 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+> and Nd^<3+>. The glass-ceramics A wer … More e prepared by sintering a glass 45CaO・45Al_2O_3・10SiO_2 (mol%) containing O.5Eu_2O_3+1Nd_2O_3 under a 2%H_2+98%Ar reducing atmosphere. In the glass-ceramics A, three crystalline phases, CaAl_2O_4(CA), CaAl_4O_7(CA2) and Ca_2Al_2SiO_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_2O_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. When the glasses were melted with reducing agent like sugar and partially crystallized under a reducing atmosphere glass-ceramics showed excellent LLP properties. The glass-ceramics with LLP precipitated akermanite type crystals co-doped with Eu^<2+> and Dy^<3+> were also obtained by melting and crystallizing under reducing conditions. Less