Effect of alumina content and heat treatment on microstructure and upconversion emission of Er^(3+)ions in oxyfluoride glass-ceramics

作     者：Mohammad Hasan Imanieh Bijan Eftekhari Yekta Vahak Marghussian Inocencio Rafael Martin Benenzuela Alberto Hernandez Creus Saeed Shakhesi Esmaeil Eslami 

作者机构：Department of MaterialsCeramic DivisionIran University of Science and Technology Nanotechnology Department Engineering Research Institute Department of Física FundamentalElectrónicay SistemasUniversity of La LagunaC.Astrofísico Francisco Sánchezs/n E-38206 La LagunaTenerifeSpain MALTA Consolider TeamUniversity of La LagunaC.Astrofísico Francisco Sánchezs/n E-38206 La LagunaTenerifeSpain Department of Química FísicaInstituto de Materialesy NanotecnologíaUniversity of La Laguna38205-La LagunaTenerifeSpain Nanotechnology DepartmentEngineering Research Institute Tehran Department of PhysicsIran University of Science and Technology (IUST)NarmakTehranIran 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2012年第30卷第12期

页      面：1228-1234页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 08[工学] 0708[理学-地球物理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 

基　　金：Project supported by ACIISI of Gobierno de Canarias (ID20100152) Ministerio de Economíay Competitividad of Spain(MINECO)within the National Program of Materials(MAT2010-21270-C04-02/-03/-04) the Consol-ider-Ingenio 2010 Program(MALTACSD2007-0045,www.malta-consolider.com) ACIISI(Gobierno de canarias)project ID20100152 governments of Spainand India for the award of a project within the indo-Spanish Joint Programme of Cooperation in Science and Technology(PRI-PIBIN-2011-1153/DST-INT-Spain-P-38-11) 

主　　题：oxyfluorides glass-ceramic CaF2 nanocrystals SiO3/Al2O3 ratio rare earths 

摘      要：The effect of alumina content and heat treatment temperature and time, on microstructure and Er3＋ （0.5 mol.%） emission of oxyfluoride glass-ceramics were investigated in this research. Two values of 1.8 （SA1.8Er0.5） and 2.18 （SA2.18Er0.5） were selected in this research for SiO2/Al2O3 ratio. According to DTA results, precursor glasses were heat treated at 630, 660 and 690 ℃ for 4 h and some glasses were also heat treated at 630 ℃ for 48 and 72 h. The results indicated that alumina content had significant effect on phase separation and viscosity of the glasses. Therefore the size, size distribution, and volume concentration of nano CaF2 crystals which precipitated during the heat treatment depended on alumina content of the glass. Due to the much smaller size of the precipitated CaF2 crystals in the glasses of low alumina content, these samples maintained excellent transparency and had narrower crystal size distribution than the high alumina glasses. The crystal size was increased markedly with the temperature increasing from 630 to 690 ℃. On the other hand a slight increase was observed in the crystal size by raising the heat treatment time in both glasses. Results indicated that in low alumina content glass （SA2.18Er0.5） the size of CaF2 nanocrystals was controlled in one order of magnitude. The increase of heat treatment time and temperature led to the incorporation of Er3＋ ions into CaF2 crystalline phase, increasing significantly the upconversion intensity. After heat treatment at 690 ℃for 4 h, atomic force microscope （AFM） revealed the development of small crystals with an average size of 80 and 30 nm in SA1.8Er0.5 and SA2.18Er0.5 samples, respectively.