12008-02-5Relevant articles and documents
Chemical synthesis and microstructure of nanocrystalline RB6(R = Ce, Eu)
Lihong, Bao,Wurentuya,Wei, Wei,Yingjie, Li,Tegus
, p. 235 - 239 (2014)
Nanocrystalline RB6(R = Ce and Eu) have been successfully synthesized by a solid-state reaction of CeO2and Eu2O3with NaBH4at a temperature range of 900-1200 °C. Phase composition, grain morphology, microstructure and valence states of RB6were investigated by using XRD, FESEM, HRTEM and XANES measurements. Results show that all the synthesized hexaborides are composed of single-phase nanoparticles with cubic morphology. The FFT patterns of HRTEM images reveal that the hexaborides have a high crystallinity with CaB6-type cubic structure. The present preparation technique is as a novel and invaluable for the developments of highly crystallized RB6nanoparticles.
SYNTHESIS OF CERIUM AND GADOLINIUM BORIDES USING BORON CAGE COMPOUNDS AS A BORON SOURCE.
Itoh, H.,Tsuzuki, Y.,Yogo, T.,Naka, S.
, p. 1259 - 1266 (1987)
Cerium borides (CeB//4 and CeB//6) and gadolinium borides (GdB//4 and GdB//6) were synthesized using boron cage compounds M//2(B//1//0H//1//0)//3 (M equals Ce and Gd) as a boron source. A mixture of hexaboride (CeB//6 or GdB//6) and amorphous boron was formed by thermal decomposition above 1000 degree C or 1200 degree C, respectively. These borides contained a small amount of inclusions (oxides, borates, etc. ) which can be removed by acid treatment in HCl solution with the formation of single phases.
Single-crystal x-ray diffraction study on Ce1-xLaxB6 solid solutions
Blomberg,Merisalo,Korsukova,Gurin
, p. 313 - 319 (1991)
Single crystals of Ce1-xLaxB6, with x = 0, 0.25, 0.50 and 0.75, prepared by crystallization from solutions in molten aluminium, were investigated by X-ray diffraction. Experimental data were corrected for thermal diffuse s
Solar control dispersions and coatings with rare-earth hexaboride nanoparticles
Takeda, Hiromitsu,Kuno, Hiroko,Adachi, Kenji
, p. 2897 - 2902 (2008)
Nanoparticle dispersions of rare-earth hexaborides have been prepared using a media agitation mill and have been examined for optical properties. High visible light transmittance coupled with strong absorption in the near-infrared (NIR) wavelengths suitable for solar control windows are reported for hexaboride nanoparticle dispersions with particle size dependence and the effect of artifacts. Nanoparticulate LaB6 shows the largest NIR absorption among rare-earth hexaborides. NIR absorption is considered to arise from the free electron plasmon resonance. On decreasing the particle size below 120 nm, both visible light transmittance and NIR absorption are found to increase gradually until the size of 18-26 nm when they reach the maximum, and then decrease again at below 18 nm. Zirconia contamination and formation of lanthanum oxide were found to be involved during the milling process, leading to small additional absorptions around 300 and 650 nm, respectively.
Thermodynamic properties of the rare earth borides and carbides in a wide temperature range
Bolgar, A. S.,Muratov, V. B.,Blinder, A. V.,Kryklya, A. I.,Suodis, A. P.
, p. 127 - 128 (1993)
For the first time a systematic study was made of the heat capacity and enthalpy of the rare earth tetra- and hexaborides and sesqui- and dicarbides in the temperature range 60-2300 K.
The system Ce-Zn-B at 800 °c
Malik,Sologub,Giester,Rogl
, p. 2840 - 2848 (2011)
The isothermal section for the system CeZnB has been established at 800 °C using electron microprobe analysis and X-ray powder diffraction. No ternary compounds exist and mutual solid solubilities of binary phases are negligible. In the concentration range of 10.010.5 at% Ce two structural modifications have been confirmed: high temperature βCe2Zn 17 above ～750 °C with the Th2Zn17 type (R3m, a=0.90916(4) nm, c=1.3286(1) nm) and low temperature αCeZn 7 (Ce1-xZn52x; x～0.33) up to 750 °C for which we attributed the TbCu7 type (P6/mmm, a=0.52424(2), c=0.44274(1) nm). The crystal structure of CeZn7 was derived from the Rietveld refinement of X-ray powder intensities. Precise data on atom site distribution and positional parameters have been furthermore provided from X-ray single crystal refinements for two compounds, for which crystal structures hitherto have only been derived from X-ray diffraction photographs: Ce 3Zn11 (Immm, a=0.45242(2) nm, b=0.88942(3) nm, c=1.34754(4) nm) and Ce3Zn22 (I41/amd; a=0.89363(2) nm, c=2.1804(5) nm).
Preparations of lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6)
Wang, Yu,Chou, Kuo-Chih,Zhang, Guo-Hua
, p. 1954 - 1966 (2021/11/24)
Due to strong anti-poisoning ability, good emission stability, high emission current density, lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6) have been maturely applied in electron emission emitter. In this paper, a new manufacturing method for LaB6 (or CeB6) powder was proposed by using La2O3 (or CeO2), B4C, and Al as raw materials. After high-temperature reaction in the range of 1673–1773?K and the following alkaline leaching at 90°C, LaB6 or CeB6 powder with particle size of about 10?μm was obtained. Furthermore, by Al metal flux method, the obtained powder was used to manufacture single crystal block with size of several millimeters.
