(Ca,Fe)共掺铈酸镧陶瓷的制备及红外辐射性能研究

以La₂O₃、CeO₂、CaO和Fe₂O₃为起始原料, 采用高温固相烧结工艺制备得到(Ca,Fe)共掺铈酸镧(La_1.9Ca_0.1Ce_1.9Fe_0.1O₇)红外辐射陶瓷材料。采用X射线衍射仪、扫描电子显微镜、能谱仪、紫外-可见-近红外(UV-Vis-NIR)分光光度计分别对样品的物相组成、显微结构、化学成份、UV-Vis-NIR反射率及UV-Vis吸收进行了表征, 同时采用IR-2双波段红外发射率测量仪测试了样品3~5 μm波段的红外发射率。结果表明: 掺杂元素(Ca, Fe)均固溶进入铈酸镧晶格, 共掺后样品的晶体结构也为萤石结构; (Ca,Fe)共掺样品内部形成杂质能级, 强化了自由载流子吸收与杂质能级吸收, 使样品红外短波段(0.75~5 μm)性能由高反射转变为高吸收(辐射), 其中在0.75~2.5 μm波段的平均红外吸收率为0.88, 3~5 μm波段的红外发射率为0.752, 与未掺杂样品相比分别提高了1660%与60%。

Preparation and Infrared Radiation Property of Lanthanum-cerium Oxide Ceramics by (Ca,Fe) Co-doping

(Ca,Fe) co-doped lanthanum-cerium oxide (La_1.9Ca_0.1Ce_1.9Fe_0.1O₇) infrared radiation ceramics were prepared via solid state reaction by using La₂O₃, CeO₂, CaO and Fe₂O₃ as starting materials. The phase, micro-structure, chemical composition, UV-Vis-NIR reflectivity spectrum, and UV-Vis absorption spectrum of the samples were characterized by X-ray diffractometer, scanning electron microscopy, energy dispersive X-ray spectroscopy, and UV-Vis-NIR spectrophotometer. The infrared emissivity of the samples in 3-5 μm waveband was also measured by an infrared emissometer. The phase and EDS analysis showed the co-doped sample also had fluorite structure, indicating that Ca and Fe irons entered the crystal lattice of lanthanum-cerium oxide. An impurity energy level was introduced into lanthanum-cerium oxide by co-doping of Ca and Fe irons, which enhanced the free-carrier absorption and impurity energy level absorption of the sample. This led to a significant increase of absorption and emission in the region of 0.75-5 μm, transforming lanthanum-cerium oxide ceramic from high reflection to high absorption (radiation) ceramic after (Ca,Fe) co-doping. The (Ca,Fe) co-doped sample exhibited an absorptivity of 0.88 in 0.75-2.5 μm waveband and an infrared emissivity of 0.752 in 3-5 μm waveband, increasing by 1660% and 60%, respectively, as compared with that of pure La₂Ce₂O₇ ceramic sample.