Novel synthesis of cerium hexaboride by hexamine route

Amalajyothi, K.; Berchmans, L. John

doi:10.3103/s106138620804002x

Cited by 9 publications

(3 citation statements)

References 28 publications

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“…Other routes, like solid state reactions (at 1800 C), 24 electrolysis 25 and solvothermal routes, 26,27 are known, which are generally carried out at high temperature. However, low temperature hexylamine 28 and ionothermal routes 29 are also known. The hexyl amine route leads to the production of large particles with irregular morphologies while the ionothermal route leads to the formation of nanoparticles of $8 nm.…”

Section: Introductionmentioning

confidence: 99%

Vertically aligned cerium hexaboride nanorods with enhanced field emission properties

et al. 2012

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Cerium hexaboride is a well-known material for the filaments of electron microscopes due to its field emission properties (high brightness electron source) and its long service life. The synthesis of cerium hexaboride (and most other borides) normally requires very high temperatures (1500 C-1700 C) and high pressures. Thus, the low temperature synthesis of cerium hexaboride at ambient pressure is a challenge. The present study highlights the synthesis of vertically aligned cerium hexaboride nanorods which offer better field emission properties with the highest field enhancement factor reported so far. The optimization of the process for obtaining vertically aligned cerium hexaboride nanorods involves three different stages. First, the low temperature synthesis of polycrystalline cerium hexaboride; second, the fabrication of cerium hexaboride films having vertically oriented nanorods (by spin coating and slow evaporation) and third, the enhancement of the field emission properties. The synthesis of cerium hexaboride nanorods has been carried out by a low temperature borothermal reduction process using a cerium precursor (synthesized via a reverse micellar route and a hydrothermal route) and boron as the starting materials. The borothermal reduction of the cerium precursors has been carried out at low temperature ($1300 C) and ambient pressure in an inert atmosphere. The field emission studies of the vertically aligned nanorods of diameter 30 nm and 200 nm show a field enhancement factor of 3863 and 3658, respectively, which is nearly seven-fold higher than the maximum field enhancement factor known so far.

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Section: Introductionmentioning

confidence: 99%

Vertically aligned cerium hexaboride nanorods with enhanced field emission properties

et al. 2012

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“…The joint electrodeposition of lanthanum-boron and gadolinium-boron systems in halide melts have been discussed by Khushkhov et al [19]. Synthesis of cerium hexaboride (CeB 6 ) was reported using hexamine [20] and citric acid [21]. A nanotube of gadolinium hexaboride has been tried by molten salt electrolysis by Bukatova and Kuznetsov [22].…”

Section: Introductionmentioning

confidence: 99%

Electrosynthesis of samarium hexaboride using tetra borate melt

Berchmans

Visuvasam

Angappan

et al. 2010

Ionics

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Fine crystals of samarium hexaboride were synthesized by molten salt electrolysis using samarium oxide, sodium tetraborate and lithium fluoride. The electrolysis was performed at 900°C in argon atmosphere at various current densities ranging from 1.0 to 2.3 A/cm 2 . The molar ratio of the reactants [Sm:B] was varied from 1:6 to 1:12. The deposited crystals were examined for the phase purity using X-ray diffraction analysis. The effect of current density and the influence of molar concentration of the reactants were evaluated. The morphological features of the crystals were examined using scanning electron microscopy (SEM). Pure crystals of SmB 6 are obtained at a current density of 1.8 A/ cm 2 . The SEM images reveal that the crystals are packed in a cubic manner, exhibiting irregular morphology. The average crystallite size of the powders is found to be between 72 and 83 nm. The mechanism of formation of SmB 6 is explained by the joint deposition of B and Sm at the Mo cathode.

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“…The combustion reaction of hexamine can be represented as (CH 2 ) 6 N 4 + 10O 2 -> 4CO + 2CO 2 +2NO+2NO 2 +6H 2 O (1) Hexamine was tried as a fuel for the preparation of LiMn 2 O 4 nanoparticles 15 , alumina nanofibers 16 , zinc oxide 17 , dispersed bimetallic carbides and nitrides 18 . Recently the rare earth boride, cerium hexaboride has been synthesized using this compound as the fuel 19 . To our knowledge, no one has tried hexamine as the fuel for the synthesis of lithium nickelate by combustion synthesis route.…”

Section: Introductionmentioning

confidence: 99%

Combustion Synthesis of Lanthanum Substituted LiNiO₂ Using Hexamine as a Fuel

Kayalvizhi¹,

Berchmans

2010

Journal of Chemistry

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Lithium nickelate and its lanthanum substituted compound have been successfully prepared by combustion synthesis process using LiNO 3 , Ni(NO 3 ) 2 .6H 2 O and La(NO 3 ) 3 .6H 2 O. Hexamine is used as fuel. The physicochemical properties of the powders were investigated by thermal analysis (TGA/DTA). The crystalline powders were characterized for their phase identification using x-ray diffraction analysis (XRD).FT-IR spectroscopy was used to study the local structure of the oxide environment. The morphological features of the powders were characterized by scanning electron microscopy (SEM). DTA analysis reveals the evolution of an exothermic peak at 465 °C indicating the rapid decomposition of the hexamine and dissociation of nitrate salts, forming the final compound lithium nickealte. The XRD pattern reveals the rhombohedral structure of LiNiO 2 with trigonal symmetry comprising of two interpenetrating close packed FCC sub-lattices. The lattice constant values 'a' and 'c' are in good agreement with the reported data. In the FT-IR spectra, vibrational bands are identified in the range of 400-800 cm -1 representing the NiO 2 layer. LiNiO 2 exhibits a very fine crystalline structure with an irregular morphology. The La substituted LiNiO 2 powder has shown a smooth-edged polyhedral structure with an average particle size of 5-10 µm.

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Novel synthesis of cerium hexaboride by hexamine route

Cited by 9 publications

References 28 publications

Vertically aligned cerium hexaboride nanorods with enhanced field emission properties

Vertically aligned cerium hexaboride nanorods with enhanced field emission properties

Electrosynthesis of samarium hexaboride using tetra borate melt

Combustion Synthesis of Lanthanum Substituted LiNiO₂ Using Hexamine as a Fuel

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Novel synthesis of cerium hexaboride by hexamine route

Cited by 9 publications

References 28 publications

Vertically aligned cerium hexaboride nanorods with enhanced field emission properties

Vertically aligned cerium hexaboride nanorods with enhanced field emission properties

Electrosynthesis of samarium hexaboride using tetra borate melt

Combustion Synthesis of Lanthanum Substituted LiNiO2 Using Hexamine as a Fuel

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Product

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Combustion Synthesis of Lanthanum Substituted LiNiO₂ Using Hexamine as a Fuel