利用固相反应法在1 300 ℃下合成La0.8Ca0.2Fe0.5X0.5O3(X=Fe、Cu、Cr、Mn)氧化物,并对它们在近红外波段的发射率进行了研究和比较,通过XRD、XPS、FT-IR等对样品进行分析和表征.研究结果表明,合成的La0.8Ca0.2Fe0.5X0.5O3型氧化物样品为单相正交晶系.掺杂后的试样较LaFeO3在200~2 500 nm近红外波段的发射率均提高60%以上,其中Ca-Cr>Ca-Cu>Ca>Ca-Mn>不掺,可能是掺杂引入Fe4+杂质能级增强了自由载流子浓度及其带隙之间的跃迁,不同元素掺杂引起Fe3+Fe4+的跃迁程度与氧空位的浓度存在差异,导致不同掺杂元素发射率不同.La0.8Ca0.2Fe0.5X0.5O3型氧化物材料均具有优异的近红外辐射性能,能够在高温热工节能领域发挥作用.
La0.8Ca0.2Fe0.5X0.5O3(X=Fe, Cu, Cr, Mn) oxides were synthesized by solid phase reaction at 1 300 ℃.They were studied and compared in near infrared emissivity and characterized by XRD, XPS and FT-IR.The results show that the synthesized La0.8Ca0.2Fe0.5X0.5O3 type oxide sample is single phase.The emissivity of LaFeO3 in the near infrared band of 200-2 500 nm was increased by more than 60% after dopingand the Ca-Cr>Ca-Cu>Ca>Ca-Mn>Ca-Cr was not mixed.The dopedFe4+ impurity level enhanced free carrier concentration and transition band gap.The different doping concentration of Fe3+ caused different transition Fe4+and oxygen vacancies, resulting in different emission rates of different doping elements.La0.8Ca0.2Fe0.5X0.5O3 type oxide materials have excellent near infrared radiation properties, which can play a role in the field of high temperature thermal energy conservation.
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