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| 铁酸镧B位掺Mn/Co/Cr试样的红外辐射性能与机理 | |
| 引用本文： | 刘庆生,程华金,谈成亮,邱建民,涂弢.铁酸镧B位掺Mn/Co/Cr试样的红外辐射性能与机理[J].化工进展,2020,39(5):1897-1906. |
| 作者姓名： | 刘庆生 程华金 谈成亮 邱建民 涂弢 |
| 作者单位： | 1.江西理工大学材料冶金化学学部，江西 赣州 341000;2.赣州嘉通新材料有限公司，江西 赣州 341000;3.江西理工大学应用科学学院，江西 赣州 341000 |
| 基金项目： | 国家自然科学基金;江西省教育厅科学技术研究项目 |
| 摘 要： | 采用高温固相烧结法制备了粉体材料LaFeO3、LaFe0.75Co0.25O3、LaFe0.75Cr0.25O3和LaFe0.75Mn0.25O3，通过XRD、FTIR、SEM、XPS等检测手段对材料进行表征，同时运用CASTEP模块模拟计算了材料的电子能带结构和光学性质。实验结果表明：掺入Mn/Cr/Co离子后晶格发生畸变,晶格对称性降低。Mn/Cr/Co掺杂后的粉体材料在近中红外波段发射率排序为：掺Mn>掺Co>掺Cr>纯LaFeO3，其中掺Mn在0.2～2.5μm波段为0.8722，2.5～5μm波段为0.6755，远大于纯LaFeO3的发射率（近中红外波段发射率均为0.5左右）。发射率提升的机理在于：Mn掺杂后,引入了Mn3+杂质能级，产生了激活能小的Mn3+?Mn4+跳跃小极化子，电子-氧空位载流子吸收亦增强，同时体系的晶格畸变导致振动吸收加剧。第一性原理计算结果表明掺杂Mn/Cr/Co材料的禁带宽度分别0.793eV、2.406eV、1.722eV均小于纯LaFeO3的3.817eV，结合态密度计算结果分析其原因，主要Mn3d、Cr3d、Co3d轨道与O2p轨道杂化形成杂质能级，同时Mn3d、Cr3d、Co3d在导带也存在态密度峰，且峰的位置都比LaFeO3峰更靠近费米能级，作为新的导带底相当于缩短了价带顶到导带底之间的间隙宽度。LaFe0.75Mn0.25O3材料在近中红外波段的优异辐射性能表现，可作为耐高温抗氧化高发射率材料在高温热工炉窑具有潜在应用前景。 |
| 关 键 词： | 钙钛矿 掺杂 红外发射率 禁带宽度 红外辐射材料 |
Infrared radiation properties and mechanism of LaFeO3 samples that B-doped Mn/Co/Cr |
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| LIU Qingsheng,CHENG Huajin,TAN Chengliang,QIU Jianmin,TU Tao.Infrared radiation properties and mechanism of LaFeO3 samples that B-doped Mn/Co/Cr[J].Chemical Industry and Engineering Progress,2020,39(5):1897-1906. | |
| Authors: | LIU Qingsheng CHENG Huajin TAN Chengliang QIU Jianmin TU Tao |
| Affiliation: | 1.Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China 2.Ganzhou Jiatong New Material Co. , Ltd, Ganzhou 341000, Jiangxi, China 3.Applied Science College of Jiangxi, University of Science and Technology, Ganzhou 341000, Jiangxi, China |
| Abstract: | LaFeO3 and LaFe0.75X0.25O3 (X=Co/Cr/Mn) samples were prepared via a high temperature solid phase sintering method. The samples were characterized through XRD, FTIR, SEM and XPS at the same time. The electronic band structure and optical properties of these samples were calculated using the CASTEP module. The results showed that the lattice was distorted, and the lattice symmetry was reduced after doping Co/Cr/Mn ions. The emissivity in the range of near-mid-infrared was as following: Mn-doped＞Co-doped＞Cr-doped＞pure LaFeO3. The emissivity of LaFe0.75Mn0.25O3 was 0.8722 and 0.6755 in the 0.2～2.5μm and 2.5～5μm bands, respectively, which were much bigger than that of pure LaFeO3 with approximately 0.5 in the near-mid-infrared band. The mechanism of improvements in emission performance was analyzed. By doping Mn ions, the small Mn3+?Mn4+ hopping polaron with low activation energy was generated, electron-oxygen vacancy carrier absorption was enhanced, and the lattice distortion of Mn-doped sample caused an increase in the vibration absorption. The first-principles calculation results revealed that the forbidden band width of LaFeO3 doped with Mn/Cr/Co were 0.793eV, 2.406eV and 1.722eV, respectively, all lower than 3.818eV of pure LaFeO3. Combining with the analysis of state density calculation results, it was mainly because Mn3d, Cr3d, Co3d and O2p orbitals were hybridized to form impurity levels. Also, the orbitals of Mn3d, Cr3d and Co3d occurred state density peaks in the conduction band, where peak positions were much closer to the Fermi energy level than that of LaFeO3, which shorten the gap width between valence band top and conduction band bottom. The LaFe0.75Mn0.25O3 had good radiation performance in the near-mid-infrared region and showed potential for application in a high-temperature furnace. |
| Keywords: | perovskite doping infrared emissivity forbidden band width infrared radiation material |
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