The aim of this work was to prepare MgF2 translucent ceramic by using nanopowders as raw materials and to study its properties.The MgF2 nanopowders were prepared using chemical precipitation and the translucent cerami...The aim of this work was to prepare MgF2 translucent ceramic by using nanopowders as raw materials and to study its properties.The MgF2 nanopowders were prepared using chemical precipitation and the translucent ceramics were fabricated by hot-pressing sintering in a vacuum environment. X-ray diffraction analysis showed that the powders were homogeneous with an average particles size about 13 nm. By comparing the results of transmission electron microscopy, it could be concluded that the porous structure of precursor powders could be improved by calcination. The SEM images of MgF2 indicated that the as-prepared ceramics were well densified at 900 ℃. The photo of the ceramic sample showed that high translucence is a main breakthrough in the field of MgF2 materials preparation. For the translucent ceramic sample sintered at 900 ℃, the Viekers hardness and density were 5.55 GPa and 98.74%, respectively, and its highest transmittance with thickness of lmm reached 87% in the wavelength from 2.5 lain to 10 btm, all which made it advantageous to be a kind of infrared windows and dome materials.展开更多
The transparent and thermal developments of high-purity Al_2O_3 doped with different levels of Nd_2O_3 were investigated. Dopant levels ranged from 500–1500 ppm（Nd/Al atomic ratio）. The samples were characterized w...The transparent and thermal developments of high-purity Al_2O_3 doped with different levels of Nd_2O_3 were investigated. Dopant levels ranged from 500–1500 ppm（Nd/Al atomic ratio）. The samples were characterized with X-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, transmittance spectroscopy and specific heat measurement. Results revealed that with proper Nd doped, Nd^（3＋） ions solid dissolved in Al_2O_3 lattice, resulting in small and uniform grain and high bonding vibration, which was beneficial to transparent and thermal properties. With 1000 ppm Nd doped, Al_2O_3 translucent ceramics showed a total transmittance of 89% and thermal conductivity of 41.7 W/m/K, indicating a potential application as substrate for effective heat dissipation and multi emitting surface in LEDs module.展开更多
基金Funded by the National Natural Science Foundation of China(No.51072144)the Project for Science and Technology Plan of Wuhan City(No.201210231092)
文摘The aim of this work was to prepare MgF2 translucent ceramic by using nanopowders as raw materials and to study its properties.The MgF2 nanopowders were prepared using chemical precipitation and the translucent ceramics were fabricated by hot-pressing sintering in a vacuum environment. X-ray diffraction analysis showed that the powders were homogeneous with an average particles size about 13 nm. By comparing the results of transmission electron microscopy, it could be concluded that the porous structure of precursor powders could be improved by calcination. The SEM images of MgF2 indicated that the as-prepared ceramics were well densified at 900 ℃. The photo of the ceramic sample showed that high translucence is a main breakthrough in the field of MgF2 materials preparation. For the translucent ceramic sample sintered at 900 ℃, the Viekers hardness and density were 5.55 GPa and 98.74%, respectively, and its highest transmittance with thickness of lmm reached 87% in the wavelength from 2.5 lain to 10 btm, all which made it advantageous to be a kind of infrared windows and dome materials.
基金supported by the project of Natural Science Foundation of Zhejiang Province(LY15F050005 and LZ14B010001)
文摘The transparent and thermal developments of high-purity Al_2O_3 doped with different levels of Nd_2O_3 were investigated. Dopant levels ranged from 500–1500 ppm（Nd/Al atomic ratio）. The samples were characterized with X-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, transmittance spectroscopy and specific heat measurement. Results revealed that with proper Nd doped, Nd^（3＋） ions solid dissolved in Al_2O_3 lattice, resulting in small and uniform grain and high bonding vibration, which was beneficial to transparent and thermal properties. With 1000 ppm Nd doped, Al_2O_3 translucent ceramics showed a total transmittance of 89% and thermal conductivity of 41.7 W/m/K, indicating a potential application as substrate for effective heat dissipation and multi emitting surface in LEDs module.
