Magnesium borate (7MgO·2B2O3·7H2O),spherical flower-like morphologies,composed from nano-flake self-assemblies,was successfully prepared by microwave hydrothermal method with magnesium nitrate hexahydrate,borax and ammonia as reactants.The structure,properties and morphology were systematically characterized by XRD,TG-DTA,IR and SEM.Magnesium borate luminescent precursors (7MgO·2B2O3·7H2O∶Tb3+) were synthesized by doping Tb3+ into the matrix material.After calcination,magnesium borate phosphor(3MgO·B2O3∶Tb3+) was obtained.Results of fluorescence spectra indicated that there was a strong green emission at 541 nm corresponding to the characteristic 5D4-7F5 of Tb3+ transition under excitation at 246 nm.The optimum doping concentration was 1％,and the optimum temperature was 650 ℃.The high concentration of doped Tb3+ ions could cause the luminescence intensity decrease,which may be ascribed to the concentration quenching effect.%以六水合硝酸镁、硼砂、氨水为原料,在微波水热条件下制备硼酸镁基质,经X射线衍射(XRD)、热重-差热分析(TG-DTA)、红外光谱分析(IR)及扫描电镜(SEM)分析表明硼酸镁基质的组成为7MgO·2B2O3·7H2O,形貌为纳米薄片团簇而成的球状花.通过稀土铽(Tb3+)掺杂,先微波水热合成硼酸镁荧光粉前躯体7MgO·2B2O3·7H2O∶Tb3+,再经焙烧得硼酸镁荧光粉3MgO·B2O3∶Tb3+.实验表明,前驱体中Tb3+适宜掺杂量为1％(硝酸铽加入量为硝酸镁物质的量的1％),较佳的焙烧温度为650℃;在波长为246 nm激发光下,荧光粉以541 nm绿光发射为主,对应5D4-7F5特征跃迁.当Tb3+掺杂量增大时,由于发生浓度淬灭效应而使荧光粉发光减弱.
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