12008-02-5Relevant academic research and scientific papers
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.
Mechanochemical Synthesis of High Crystalline Cerium Hexaboride Nanoparticles from CeO2-B2O3-Mg Ternary System
Torabi, Omid,Naghibi, Sanaz,Golabgir, Mohammad-Hossein,Jamshidi, Amin
, p. 379 - 384 (2016)
High crystalline cerium hexaboride (CeB6) nanoparticles (NPs) were synthesized using mixture of magnesium (Mg), cerium oxide (CeO2) and boron oxide (B2O3) via the mechanochemical process at room temperature. Based on the results, magnesiothermic reduction of B2O3 occurred after about 2 h of milling in a mechanically induced self-sustaining reaction (MSR). The significant amount of heat produced by the reduction reaction resulted in CeO2 reduction to elemental Ce which finally reacted with elemental B and formed CeB6 compound. According to XRD analyses, the degree of crystallinity and lattice parameter of the product was calculated about 93 % and 4.1458 ?, respectively. The morphology observations revealed that the synthesized CeB6 had semi-cubic shape with the range of size 25-60 nm. The synthesis of CeB6 during the thermal treatment was studied by simultaneous thermal analysis (STA) technique. It was found that the reduction of B2O3 took place after melting of Mg meanwhile, no CeB6 phase achieved even up to 1100 °C.
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.
Direct low-temperature synthesis of RB6 (R=Ce, Pr, Nd) nanocubes and nanoparticles
Zhang, Maofeng,Wang, Xiaoqing,Zhang, Xianwen,Wang, Pengfei,Xiong, Shenglin,Shi, Liang,Qian, Yitai
, p. 3098 - 3104 (2009)
Rare-earth hexaborides (RB6, R=Ce, Pr, Nd) nanocrystals were prepared by a facile solid state reaction in an autoclave. Single-crystalline RB6 nanocubes were fabricated at 500 °C starting from B2O3, RCl3/s
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
On phase equilibria and crystal structures in the systems Ce-Pd-B and Yb-Pd-B. Physical properties of R2Pd13.6B5 (R=Yb, Lu)
Sologub, Oksana,Rogl, Peter,Salamakha, Leonid,Bauer, Ernst,Hilscher, Gerfried,Michor, Herwig,Giester, Gerald
, p. 1013 - 1037 (2010)
Phase equilibria and crystal structures of ternary compounds were determined in the systems Ce-Pd-B and Yb-Pd-B at 850 °C in the concentration ranges up to 45 and 33 at% of Ce and Yb, respectively, employing X-ray single crystal and powder diffraction. Phase relations in the Ce-Pd-B system at 850 °C are governed by formation of extended homogeneity fields, τ2-CePd8B2-x (0.103-Ce3Pd25-xB8-y (1.063Bx (03. Crystallographic parameters for the new structure type τ2-CePd8B2-x (space group C2/c, a=1.78104(4) nm, b=1.03723(3) nm, c=1.16314(3), β=118.515(1)° for x=0.46) were established from X-ray single crystal diffraction. The crystal structures of τ2-CePd8B2-x and τ3-Ce3Pd25-xB3-y are connected in a crystallographic group-subgroup relationship. Due to the lack of suitable single crystals, the novel structure of τ1-Ce6Pd47-xB6 (x=0.2, C2/m space group, a=1.03594(2) nm, b=1.80782(3) nm, c=1.01997(2) nm, β=108.321(1)°) was determined from Rietveld refinement of X-ray powder diffraction data applying the structural model obtained from single crystals of homologous La6Pd47-xB6 (x=0.19) (X-ray single crystal diffraction, new structure type, space group C2/m, a=1.03988(2) nm, b=1.81941(5) nm, c=1.02418(2) nm, β=108.168(1)°). The Yb-Pd-B system is characterized by one ternary compound, τ1-Yb2Pd14B5, forming equilibria with extended solution YbPd3Bx, YbB6, Pd5B2 and Pd3B. The crystal structures of both Yb2Pd14B5 and isotypic Lu2Pd14B5 were determined from X-ray Rietveld refinements and found to be closely related to the Y2Pd14B5-type (I41/amd). The crystal structure of binary Yb5Pd2-x (Mn5C2-type) was confirmed from X-ray single crystal data and a slight defect on the Pd site (x=0.06) was established. The three structures τ1-Ce6Pd47-xB6, τ2-CePd8B2-x and τ3-Ce3Pd25-xB8-y are related and can be considered as the packings of fragments observed in Nd2Fe14B structure with different stacking of common structural blocks. Physical properties for Yb2Pd13.6B5 (temperature dependent specific heat, electrical resistivity and magnetization) yielded a predominantly Yb-4f13 electronic configuration, presumably related with a magnetic instability below 2 K. Kondo interaction and crystalline electric field effects control the paramagnetic temperature domain.
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.
Ab initio structure determination of new boride CePt3B, a distorted variant of CaTiO3
Sologub,Hester,Salamakha,Leroy,Godart
, p. 10 - 17 (2002)
X ray powder diffraction and electron probe micro-analysis were used to determine the crystal structure of a ternary boride CePt3B, tetragonal in structure. The presence of two phases were identified through Rietveld refinement on the sample. Ce was found to be in a trivalent state in the compound. Magnetic susceptibility measurements also showed that the compound did not order magnetically at 2 K.
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.
Single-crystalline CeB6 nanowires
Zhang, Han,Zhang, Qi,Tang, Jie,Qin, Lu-Chang
, p. 8002 - 8003 (2005)
Considered to be one of the best electron emission materials, CeB6 nanowires are of great scientific and industrial interest. CeB6 nanowires of square cross section with about 50 nm in lateral dimension and more than several micrometers in length have been successfully produced using a chemical vapor deposition method. The nanowires are grown in the lattice direction, and both the tip top and the side surfaces are terminated with the {100} lattice planes. Copyright
