热压烧结制备MgAl_2O_4/Ce:YAG透明陶瓷及显微结构

Preparation of MgAl_2O_4/Ce:YAG Transparent Ceramics by Hot-pressed Sintering and Its Microstructure

采用金属醇盐法制备MgAl2O4前躯体,通过高温煅烧得到纯相MgAl2O4粉体,再将其与YAG:Ce荧光粉均匀混合,利用热压烧结并结合热等静压处理得到(1-x)MgAl2O4/xCe:YAG(x=10%,20%,30%,40%,质量分数,下同)透明陶瓷。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、背散射电子像(BSE)和电子能谱仪(EDS)对透明陶瓷样品进行物相和显微结构分析。结果表明,样品由MgAl2O4和YAG两相组成,YAG晶粒(8μm)均匀地分散在MgAl2O4基质中。样品(厚度为2 mm)的透过光谱中主吸收峰位于460 nm处,对530 nm光的直线透过率为40%。MgAl2O4/Ce:YAG透明陶瓷能应用到白光LED领域。

High-purity ultrafine MgAl2O4 powder was firstly synthesized by a metal-alkoxide method and calcining with magnesium,aluminum and isopropanol as precursors,and then MgAl2O4/Ce:YAG transparent ceramics were fabricated by hot-pressed sintering and hot isostatic pressed sintering technique with yttrium aluminum garnet(YAG:Ce) powder and MgAl2O4 powder.The phase composition,the microstructure and the optical transmittance of the transparent ceramics were observed using X-ray diffraction(XRD),scanning electron microscopy(SEM),back scattered electron(BSE) and energy dispersive spectroscopy(EDS).The results show that the crystal phase of the transparent ceramics is composed of both magnesium-aluminum spinel(MgAl2O4) and YAG,and the YAG phase disperses well in the matrix of MgAl2O4.The grain size of YAG is around 8 μm and the in-line transmittance of the transparent ceramics exceeds 40% at 530 nm for 2 mm thick samples.The main absorption peak centers at 460 nm.Those properties indicate that MgAl2O4/Ce:YAG transparent ceramics are promising fluorescent materials and have potential for application in white LED.