磁铅石结构铝酸盐的光—光、热—光及热传导性能的研究
发布时间：2018-11-13 09:20
【摘要】：节能减排是经济社会可持续发展的迫切需求。高温工业窑炉是重要的高能耗设备之一,降低其能耗具有重要意义。本论文针对高温工业窑炉的炉衬材料,提出开发磁铅石结构新型LnMeAl_(11)O_(19)低导热系数耐高温隔热材料,并在高温热传导等方面的应用上开展研究工作,实现高温工业窑炉的节能降耗。采用高温固相合成法制备得到了不同稀土离子Ln3+(La、Ce、Nd、Sm、Eu、Gd)和过渡金属离子Me2+(Mn、Co、Ni、Zn)取代的LnMeAl_(11)O_(19)单相材料,优化的工艺条件分别为1550°C和1600°C并保温5h,产物均为磁铅石结构,其板片状晶粒尺寸随着合成温度升高而增大,晶胞参数随Ln3+离子半径降低而减小,随Me2+原子质量增加而减小。利用无压烧结工艺制备得到了不同稀土离子和过渡金属离子取代的LnMeAl_(11)O_(19)陶瓷材料,对其力学和热物理性能进行了系统研究,发现Ln3+离子半径减小或Me2+原子质量增大会增强LnMeAl_(11)O_(19)材料的力学性能并降低其导热系数,其机制为小半径离子取代使晶胞体积收缩并导致其体积密度增大和声子散射增强。稀土离子取代产物中GdMgAl11O19在25°C至800°C温度范围的导热系数最低,为1.91-1.78W/m?K;过渡金属取代产物中LaZnAl11O19的性能最优,其抗折强度和断裂韧性分别为163.3MPa和3.3MPa?m1/2。研究了稀土离子Pr3+、Sm3+、Dy3+、Ho3+、Er3+和Tm3+单/双掺杂的LaMgAl_(11)O_(19)材料的光-光转换性能,结果发现材料的光-光转换过程、光转换光谱和激发态寿命与掺杂稀土离子4f层电子在特定能级辐射跃迁相关;发现Sm3+→Eu3+、Tm3+→Dy3+和Er3+→Sm3+三对稀土离子间具有明显的能量传递作用,其机制为辐射再吸收和共振能量传递;光转换性能浓度猝灭和温度猝灭现象的机理为激活剂离子间的级联能量传递和交叉弛豫作用。系统研究了成分和温度等因素对LaMgAl_(11)O_(19)系材料高温红外热-光转换性能的影响,研究表明稀土离子和过渡金属离子取代或掺杂可以明显提高LaMgAl_(11)O_(19)材料的高温平均发射率,其中LaMgAl_(11)O_(19):Er3+,Sm3+和LaZnAl11O19材料在800°C的平均发射率可达0.906和0.915;温度升高也能够显著增大LaMgAl_(11)O_(19)系材料的热-光转换发射光谱强度和光谱发射率。在氧化铝陶瓷片表面制备LaMgAl_(11)O_(19)涂层能够显著降低陶瓷的高温热传导性能,结果表明LaMgAl_(11)O_(19)系材料可在工业窑炉炉衬材料工作面的低导热节能隔热层新材料方面具有重要的应用前景。
[Abstract]:Energy saving and emission reduction is an urgent need for sustainable economic and social development. High temperature industrial kiln is one of the most important equipments with high energy consumption, and it is of great significance to reduce its energy consumption. In this paper, a new type of LnMeAl_ (11) O _ (19) thermal insulation material with low thermal conductivity is developed for the lining material of high temperature industrial furnace, and the research work is carried out in the application of high temperature heat conduction and so on. Energy saving and consumption reduction of high temperature industrial kiln are realized. Different rare earth ions Ln3 (La,Ce,Nd,Sm,Eu,Gd) and transition metal ion Me2 (Mn,Co,Ni,Zn) substituted LnMeAl_ (11) O _ (19) single phase materials were prepared by high temperature solid state synthesis. The optimized process conditions were 1550 掳C and 1600 掳C for 5 h, respectively. The products were magnetized lead stone structure. The plate grain size increased with the increase of synthesis temperature, and the unit cell parameters decreased with the decrease of Ln3 ion radius and with the increase of Me2 atom mass. LnMeAl_ (11) O _ (19) ceramics with different rare earth ions and transition metal ions were prepared by pressureless sintering process. The mechanical and thermo-physical properties of LnMeAl_ (11) O _ (19) ceramics were systematically studied. It is found that the decrease of Ln3 ion radius or the increase of Me2 atom mass will enhance the mechanical properties and decrease the thermal conductivity of LnMeAl_ (11) O _ (19) material. The mechanism is that the small radius ion substitution results in the contraction of the unit cell volume and the increase of its bulk density and phonon scattering. The thermal conductivity of GdMgAl11O19 in the range of 25 掳C to 800 掳C was the lowest, ranging from 1.91 to 1.78 W / mK. The properties of LaZnAl11O19 in transition metal substituents are the best, and the flexural strength and fracture toughness are 163.3MPa and 3.3 MPA / m ~ (1 / 2), respectively. The optical to optical conversion properties of rare earth ions Pr3, Sm3, Dy3, Ho3, Er3 and Tm3 doped LaMgAl_ (11) O _ (19) were studied. The optical conversion spectra and the lifetime of excited states are related to the radiation transition of the doped rare earth ions 4f layer electrons at specific energy levels. It is found that Sm3 Eu3, Tm3 Dy3 and Er3 Sm3 have obvious energy transfer between rare earth ions, the mechanism of which is radiation reabsorption and resonance energy transfer. The mechanisms of concentration quenching and temperature quenching are cascade energy transfer and cross relaxation between activator ions. The effects of composition and temperature on the thermo-optical conversion properties of LaMgAl_ (11) O _ (19) materials at high temperature were studied systematically. The results show that the high temperature average emissivity of LaMgAl_ (11) O _ (19) materials can be significantly increased by substitution or doping of rare earth ions and transition metal ions, in which LaMgAl_ (11) O _ (19): Er3, The average emissivity of Sm3 and LaZnAl11O19 materials can reach 0.906 and 0.915 at 800 掳C. The thermo-optical conversion emission spectra and the spectral emissivity of LaMgAl_ (11) O _ (19) materials can also be significantly increased by increasing the temperature. The preparation of LaMgAl_ (11) O _ (19) coatings on alumina ceramic substrates can significantly reduce the thermal conductivity of the ceramics at high temperature. The results show that LaMgAl_ (11) O _ (19) material can be used as a new material for low thermal conductivity and energy saving thermal insulation in industrial furnace lining.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ174.1;TQ054
本文编号：2328673
[Abstract]:Energy saving and emission reduction is an urgent need for sustainable economic and social development. High temperature industrial kiln is one of the most important equipments with high energy consumption, and it is of great significance to reduce its energy consumption. In this paper, a new type of LnMeAl_ (11) O _ (19) thermal insulation material with low thermal conductivity is developed for the lining material of high temperature industrial furnace, and the research work is carried out in the application of high temperature heat conduction and so on. Energy saving and consumption reduction of high temperature industrial kiln are realized. Different rare earth ions Ln3 (La,Ce,Nd,Sm,Eu,Gd) and transition metal ion Me2 (Mn,Co,Ni,Zn) substituted LnMeAl_ (11) O _ (19) single phase materials were prepared by high temperature solid state synthesis. The optimized process conditions were 1550 掳C and 1600 掳C for 5 h, respectively. The products were magnetized lead stone structure. The plate grain size increased with the increase of synthesis temperature, and the unit cell parameters decreased with the decrease of Ln3 ion radius and with the increase of Me2 atom mass. LnMeAl_ (11) O _ (19) ceramics with different rare earth ions and transition metal ions were prepared by pressureless sintering process. The mechanical and thermo-physical properties of LnMeAl_ (11) O _ (19) ceramics were systematically studied. It is found that the decrease of Ln3 ion radius or the increase of Me2 atom mass will enhance the mechanical properties and decrease the thermal conductivity of LnMeAl_ (11) O _ (19) material. The mechanism is that the small radius ion substitution results in the contraction of the unit cell volume and the increase of its bulk density and phonon scattering. The thermal conductivity of GdMgAl11O19 in the range of 25 掳C to 800 掳C was the lowest, ranging from 1.91 to 1.78 W / mK. The properties of LaZnAl11O19 in transition metal substituents are the best, and the flexural strength and fracture toughness are 163.3MPa and 3.3 MPA / m ~ (1 / 2), respectively. The optical to optical conversion properties of rare earth ions Pr3, Sm3, Dy3, Ho3, Er3 and Tm3 doped LaMgAl_ (11) O _ (19) were studied. The optical conversion spectra and the lifetime of excited states are related to the radiation transition of the doped rare earth ions 4f layer electrons at specific energy levels. It is found that Sm3 Eu3, Tm3 Dy3 and Er3 Sm3 have obvious energy transfer between rare earth ions, the mechanism of which is radiation reabsorption and resonance energy transfer. The mechanisms of concentration quenching and temperature quenching are cascade energy transfer and cross relaxation between activator ions. The effects of composition and temperature on the thermo-optical conversion properties of LaMgAl_ (11) O _ (19) materials at high temperature were studied systematically. The results show that the high temperature average emissivity of LaMgAl_ (11) O _ (19) materials can be significantly increased by substitution or doping of rare earth ions and transition metal ions, in which LaMgAl_ (11) O _ (19): Er3, The average emissivity of Sm3 and LaZnAl11O19 materials can reach 0.906 and 0.915 at 800 掳C. The thermo-optical conversion emission spectra and the spectral emissivity of LaMgAl_ (11) O _ (19) materials can also be significantly increased by increasing the temperature. The preparation of LaMgAl_ (11) O _ (19) coatings on alumina ceramic substrates can significantly reduce the thermal conductivity of the ceramics at high temperature. The results show that LaMgAl_ (11) O _ (19) material can be used as a new material for low thermal conductivity and energy saving thermal insulation in industrial furnace lining.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ174.1;TQ054
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