The lanthanum carbide alloy was induction melted in vacuum induction melting furnace from lanthanum and graphite with the mass ratio of 89：11. Lanthanum hydroxide （La（OH）3） nanopowders were prepared by a simple h...The lanthanum carbide alloy was induction melted in vacuum induction melting furnace from lanthanum and graphite with the mass ratio of 89：11. Lanthanum hydroxide （La（OH）3） nanopowders were prepared by a simple hydrolysis of lanthanum carbide at room temperature under normal atmospheric pressure without any surfactant. X-ray diffraction （XRD） showed that the nanoparticles were with a hex-agonal structure. The effect factors such as reaction time,reaction temperature and the mass ratio of lanthanum carbide powders to H2O on BET surface area of the obtained nanopowders were investigated. Furthermore,transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） showed that nanopowders behaved the morphology of short nanorod. The longitudinal growth direction of the nanorod had an angle of about 14° with the （101） lattice plane and the lateral growth direction had an angle of about 35° with the （200） lattice plane. The mechanism of formation of nanorod was discussed on the basis of the experimental results.展开更多
Sr3SiO5:Eu2+ yellow phosphors for white LEDs were synthesized by high temperature solid state reaction method under a reductive atmosphere. The crystalline phases were examined with X-ray diffraction (XRD). Luminescen...Sr3SiO5:Eu2+ yellow phosphors for white LEDs were synthesized by high temperature solid state reaction method under a reductive atmosphere. The crystalline phases were examined with X-ray diffraction (XRD). Luminescence properties were studied, and effects of various fluxing agents BaCl2, MgF2, CaF2 and BaF2 on the emission spectra were also studied. The optimal Eu2+ concentration and flux were determined. Sr3SiO5: Eu2+ was obtained by firing the sample on optimal composition and fabrication process. The sa...展开更多
基金Project supported by Shanghai Leading Academic Discipline Project (S30107)
文摘The lanthanum carbide alloy was induction melted in vacuum induction melting furnace from lanthanum and graphite with the mass ratio of 89：11. Lanthanum hydroxide （La（OH）3） nanopowders were prepared by a simple hydrolysis of lanthanum carbide at room temperature under normal atmospheric pressure without any surfactant. X-ray diffraction （XRD） showed that the nanoparticles were with a hex-agonal structure. The effect factors such as reaction time,reaction temperature and the mass ratio of lanthanum carbide powders to H2O on BET surface area of the obtained nanopowders were investigated. Furthermore,transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） showed that nanopowders behaved the morphology of short nanorod. The longitudinal growth direction of the nanorod had an angle of about 14° with the （101） lattice plane and the lateral growth direction had an angle of about 35° with the （200） lattice plane. The mechanism of formation of nanorod was discussed on the basis of the experimental results.
基金Project Supported by the Jilin Province Science and Technology Development Projects (20090348 and 20080511)
文摘Sr3SiO5:Eu2+ yellow phosphors for white LEDs were synthesized by high temperature solid state reaction method under a reductive atmosphere. The crystalline phases were examined with X-ray diffraction (XRD). Luminescence properties were studied, and effects of various fluxing agents BaCl2, MgF2, CaF2 and BaF2 on the emission spectra were also studied. The optimal Eu2+ concentration and flux were determined. Sr3SiO5: Eu2+ was obtained by firing the sample on optimal composition and fabrication process. The sa...
