Li_2CO_3-NaCl复合助熔剂对(Y,Gd)BO_3:Eu荧光粉合成的影响

Influence of Li_2CO_3NaCl Flux on Synthesis of (Y,Gd)BO_3:Eu

在合成(Y,Gd)BO3:Eu的过程中,通过加入适量助熔剂制备出了颗粒小、颗粒形貌为球形、粒径分布较窄和分散性好无团聚的(Y,Gd)BO3:Eu荧光粉,探讨了在焙烧时添加复合助熔剂对荧光粉的最低烧成温度、粒径、颗粒形貌和相对亮度的影响,利用X射线衍射、扫描电镜(SEM)、粒度分析仪和辐射光谱仪对样品进行了表征.结果显示:复合助熔剂的添加,可降低高温固相反应温度,促进硼酸盐纯相的生成,在800℃即可得到纯的(Y,Gd)BO3:Eu相,比未添加助熔剂的反应温度降低了400℃,同时有利于(002)、(100)、(102)、(110)的生长;在(Y,Gd)BO3:Eu的烧结过程中,产生黏度较低的液相有利于球形颗粒的生长,易得到颗粒尺寸分布均匀,分散性好,结晶完整的荧光粉;助熔剂的添加可以使(Y,Gd)BO3:Eu的相对发光强度提高10%以上.用此方法合成的荧光粉具备了直接实际应用的条件.

Y,Gd)BO_3:Eu phosphor particles with spherical morphology, fine size and non-aggregation characteristics were prepared by solid-state reaction under the existence of flux and the effect of Li_2CO_3NaCl flux on sintering temperature, particle size, morphology and relative brightness was investigated. The addition of Li_2CO_3-NaCl reduced the sintering temperature by 400 ℃ for pure orthoborate phase. The diffraction intensity increased with the flux, the intensity of different crystal planes was changed with the flux, e.g. crystal planes (002),(100),(102)and (110)became stronger. The particle prepared without flux have a relatively large particle size of 2.0 μm,more aggregation among product particles and rectangular shape. And the phosphors prepared with Li_2CO_3-NaCl flux were composed of small round shaped grains, about 1.0 μm in size. The relative brightness of (Y, Gd) BO_3:Eu increased by 10% with additive of Li_2CO_3-NaCl flux. The prepared particles show better morphology compared with that of the commercial product.