Nd/Yb-co-doped YAG transparent ceramic nano-powder was prepared by a sol-gel combustion method.The structure,morphology and properties were characterized by thermogravimetric-differential thermal analysis,X-ray diffra...Nd/Yb-co-doped YAG transparent ceramic nano-powder was prepared by a sol-gel combustion method.The structure,morphology and properties were characterized by thermogravimetric-differential thermal analysis,X-ray diffraction,transmission electron microscopy,infrared spectroscopy,absorption analysis and fluorescence spectroscopy,respectively.The results show that the mass loss of the powder calcinated at 900 ℃ for 3 h is 49.56%.A well-crystallized Nd/Yb:YAG nano-powder with the superior sintering performance and high purity is obtained,and the morphology of the particles with the average diameter in the range of 60-100 runs appears regular.The nano-powder exhibits an intense absorption at 808 nm,corresponding to the 4I/9/2-4F7/2 transition of Nd^(^(3+) ions,which is suitable to absorb the wavelength of 808 nm from a laser diode source.The emission peak at 1046 nm of the Nd/Yb:YAG powder is more intense than that of Nd^(^(3+):YAG powder.It is indicated that the energy absorbed by Yb^(^(3+) ions from the laser diode source can be transmitted to Nd^(^(3+) ions based on the cross relaxation process of[(4F3/2)Nd,(2F7/2)Yb]-[(479/2)Nd,(2F5/2)Yb].展开更多
A novel series of Ce^3＋-doped Yb3 Al（5-x）GaxO（12）（x = 0, 1,2, 3,4, 5） powders of ytterbium aluminum gallium garnets were synthesized by high temperature solid-state reaction in a carbon reducing atmosphere. The...A novel series of Ce^3＋-doped Yb3 Al（5-x）GaxO（12）（x = 0, 1,2, 3,4, 5） powders of ytterbium aluminum gallium garnets were synthesized by high temperature solid-state reaction in a carbon reducing atmosphere. The ytterbium aluminum garnets were characterized by X-ray powder diffraction, UV-Vis diffuse reflectance spectra, photoluminescence spectra and decay curves. Moreover, the substitution effect for the Al^3＋ sites with Ga^3＋ in 0.5 at%Ce：Yb3 Al（5-x）GaxO（12）（x = 0,1, 2, 3, 4, 5） garnets were discussed. With the increase of Ga^3＋ ion concentration, the visible absorption peaks within 400-450 nm have blue shift phenomenon,while the absorption peaks in the range of 330-350 nm and the absorption band edge red shifts.Furthermore, the short decay times are very short with less than 10 ns due to the Yb^3＋ ＋ Ce^3＋→ Yb^2＋ ＋ Ce^4＋ electron transfer reaction.展开更多
An investigation on the mechanical and thermal properties of Yb3Al5O12 is conducted by a combination of first- principles calculations and chemical bond theory calculation. Density functional theory （DFT） computatio...An investigation on the mechanical and thermal properties of Yb3Al5O12 is conducted by a combination of first- principles calculations and chemical bond theory calculation. Density functional theory （DFT） computations were performed for the structural, mechanical, and thermal properties, and the results are confirmed by chemical bond theory. Based on the calculated equilibrium crystal structure, heterogeneous bonding nature is revealed. The full set of elastic constants and mechanical properties of Yb3Al5O12 are presented for the first time. The thermal expansion coefficient of Yb3Al5O12 is calculated to be 7.5 × 10^-6 K-1 by chemical bond theory. In addition, the minimum thermal conductivity of Yb3Al5O12 is estimated to be 1.22 W m-t K-1, and the origin of such low thermal conductivity is discussed. Our theoretical results highlight the potential of Yb3Al5O12 as a prospective thermal barrier coating material.展开更多
基金supported by special project of Changchun Science & Technology Office(2014228)the Development and Reform Commission of Jilin Province(2015Y69)
文摘Nd/Yb-co-doped YAG transparent ceramic nano-powder was prepared by a sol-gel combustion method.The structure,morphology and properties were characterized by thermogravimetric-differential thermal analysis,X-ray diffraction,transmission electron microscopy,infrared spectroscopy,absorption analysis and fluorescence spectroscopy,respectively.The results show that the mass loss of the powder calcinated at 900 ℃ for 3 h is 49.56%.A well-crystallized Nd/Yb:YAG nano-powder with the superior sintering performance and high purity is obtained,and the morphology of the particles with the average diameter in the range of 60-100 runs appears regular.The nano-powder exhibits an intense absorption at 808 nm,corresponding to the 4I/9/2-4F7/2 transition of Nd^(^(3+) ions,which is suitable to absorb the wavelength of 808 nm from a laser diode source.The emission peak at 1046 nm of the Nd/Yb:YAG powder is more intense than that of Nd^(^(3+):YAG powder.It is indicated that the energy absorbed by Yb^(^(3+) ions from the laser diode source can be transmitted to Nd^(^(3+) ions based on the cross relaxation process of[(4F3/2)Nd,(2F7/2)Yb]-[(479/2)Nd,(2F5/2)Yb].
基金Project supported by National Natural Science Foundation of China(11475242,51272263)K.C.Wong Magna Fund in Ningbo University
文摘A novel series of Ce^3＋-doped Yb3 Al（5-x）GaxO（12）（x = 0, 1,2, 3,4, 5） powders of ytterbium aluminum gallium garnets were synthesized by high temperature solid-state reaction in a carbon reducing atmosphere. The ytterbium aluminum garnets were characterized by X-ray powder diffraction, UV-Vis diffuse reflectance spectra, photoluminescence spectra and decay curves. Moreover, the substitution effect for the Al^3＋ sites with Ga^3＋ in 0.5 at%Ce：Yb3 Al（5-x）GaxO（12）（x = 0,1, 2, 3, 4, 5） garnets were discussed. With the increase of Ga^3＋ ion concentration, the visible absorption peaks within 400-450 nm have blue shift phenomenon,while the absorption peaks in the range of 330-350 nm and the absorption band edge red shifts.Furthermore, the short decay times are very short with less than 10 ns due to the Yb^3＋ ＋ Ce^3＋→ Yb^2＋ ＋ Ce^4＋ electron transfer reaction.
基金supported by the National Outstanding Young Scientist Foundation for Y.C.Zhou under Grant No. 59925208the National Natural Science Foundation of China under Grant No.50832008
文摘An investigation on the mechanical and thermal properties of Yb3Al5O12 is conducted by a combination of first- principles calculations and chemical bond theory calculation. Density functional theory （DFT） computations were performed for the structural, mechanical, and thermal properties, and the results are confirmed by chemical bond theory. Based on the calculated equilibrium crystal structure, heterogeneous bonding nature is revealed. The full set of elastic constants and mechanical properties of Yb3Al5O12 are presented for the first time. The thermal expansion coefficient of Yb3Al5O12 is calculated to be 7.5 × 10^-6 K-1 by chemical bond theory. In addition, the minimum thermal conductivity of Yb3Al5O12 is estimated to be 1.22 W m-t K-1, and the origin of such low thermal conductivity is discussed. Our theoretical results highlight the potential of Yb3Al5O12 as a prospective thermal barrier coating material.
