914 resultados para AL2O3 POWDERS
Resumo:
采用传统熔融冷却的方法制备了透明Ni^2+掺杂ZnO-Al2O3-SiO2系玻璃,结合X-射线、吸收和荧光等测试手段,研究了不同热处理温度对Ni^2+掺杂透明ZnO-Al2O3-SiO2系微晶玻璃光学性质的影响。由X-射线衍射谱鉴定出微晶玻璃中析出的晶相为ZnAl2O4微晶,其尺寸在13nm以下。玻璃中没有发现近红外发光,而在微晶玻璃中存在宽带近红外发光,其可归属为八面体六配位Ni^2+离子的^3T2g(^3F)激发态向^3A2g(^3F)基态的跃迁。随热处理温度升高发光强度增强,而发射峰位则发生蓝移;荧
Resumo:
以Yb^3+-Er^3+共掺的P2O5-B2O3-R2O-MO-Al2O3(R=Li,Na,K;M=Zn,Ca,Sr,Ba)系统玻璃为研究对象,分别分析了改变B2O3,的含量,以及加入不同种类的碱金属和碱土金属氧化物对玻璃的物理化学性质的影响。研究结果表明,当B2O3的含量增加,玻璃的Tg,Tf上升,热膨胀系数下降;随着修饰体阳离子半径减小,玻璃的溶解速率下降,化学稳定性变好。
Resumo:
研究了Al2O3 ,B2O3对P2O5-Al2O3-B2O3-ZnO-Na2O-CuCl玻璃形成区的影响规律;包边玻璃的物化性质随B/(B+Al)的变化规律;以及特定组分包边玻璃的透射光谱和吸收系数。这些研究工作对高功率大尺寸钕磷酸盐激光包边玻璃的研制具有非常重要的意义。
Resumo:
The physical and thermal properties Of P2O5-Al2O3-BaO-La2O3 glasses were investigated. The effects of glass compositions on the transition temperature, thermal expansion coefficient, density, hardness and refractive index of glasses were studied. The highest hardness of the glasses is 4143.891 MPa and the lowest thermal expansion coefficient of the glasses is 71.770 x 10(-7)/° C. A phosphate glass with high mechanical strength and good thermal characteristic is obtained.
Resumo:
We report on transparent Ni2+-doped MgO-Al2O3-SiO2 glass ceramics with broadband infrared luminescence. Ni2+-doped MgO-Al2O3-SiO2 glass is Prepared by using the conventional method. After heat treatment at high temperature, MgAl2O4 crystallites are precipitated, and their average size is about 4.3nm. No luminescence is detected in the as-prepared glass sample, while broadband infrared luminescence centred at around 1315nm with full width at half maximum (FWHM) of about 300nm is observed from the glass ceramics. The observed infrared emission could be attributed to the T-3(2g)(F-3) -> (3)A(2g)(F-3) transition of octahedral Ni2+ ions in the MgAl2O4 crystallites of the transparent glass ceramics. The product of the fluorescence lifetime and the stimulated emission cross section is about 1.6 X 10(-24) s cm(2).
Resumo:
Visible upconversion luminescence was observed in Cr3+: Al2O3 crystal under focused femtosecond laser irradiation. The luminescence spectra show that the upconversion luminescence originates from the E-2-(4)A(2) transition of Cr3+. The dependence of the fluorescence intensity of Cr3+ on the pump power reveals that a two-photon absorption process dominates in the conversion of infrared radiation to the visible emission. It is suggested that the simultaneous absorption of two infrared photons produces the population of upper excited states, which leads to the characteristic visible emission from E-2 state of Cr3+.
Resumo:
The broadband emission in the 1.2 similar to 1.6 mu m region from Li2O-Al2O3-ZnO-SiO2 ( LAZS) glass codoped with 0.01mol.% Cr2O3 and 1.0mol.% Bi2O3 when pumped by the 808nm laser at room temperature is not initiated from Cr4+ ions, but from bismuth, which is remarkably different from the results reported by Batchelor et al. The broad similar to 1300nm emission from Bi2O3-containing LAZS glasses possesses a FWHM ( Full Width at Half Maximum) more than 250nm and a fluorescent lifetime longer than 500 mu s when excited by the 808nm laser. These glasses might have the potential applications in the broadly tunable lasers and the broadband fiber amplifiers. (c) 2005 Optical Society of America.
Resumo:
对透光性良好的Cr^3+:Al2O3透明多晶陶瓷的光谱性能进行了研究,其吸收光谱中吸收峰与单晶红宝石相一致,按吸收光谱和Tanabe-Sugano能级图,算出其晶场强度参数Dq及Racah参数B分别为1792cm^-1,689cm^-1,Dq/B=2.6,陶瓷中Cr^3+离子所处格位的晶体场强比单晶弱一些,但Cr^3+:Al2O3透明陶瓷仍属于强场晶体材料;当Cr^3+掺杂浓度到达0.8wt%时,陶瓷的发射谱仍保持较好的R线发射;随Cr^3+掺杂浓度的增大,激发峰位发生“红移”.在Cr^3+:Al2O3透