Preparation of titanium diboride nanopowders of different particle sizes

Volkova, L. S.; Кравченко, С. Е.; Коробов, И. И.; Колесникова, А. М.; Дремова, Н. Н.; Burlakova, A. G.; Калинников, Г. В.; Shilkin, S. P.

doi:10.1134/s0020168513110137

Cited by 8 publications

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“…As shown earlier [10][11][12], reactions between tita nium (zirconium) and boron powders in an anhydrous Na 2 B 4 O 7 ionic melt at a temperature of 800°C lead to the formation of TiB 2 and ZrB 2 nanopowders. It was of interest to investigate distinctive features of synthe sis in ionic melts with application to the preparation of HfB 2 nanopowders.…”

Section: Introductionmentioning

confidence: 63%

Preparation of hafnium diboride nanopowders in an anhydrous Na2B4O7 ionic melt

et al. 2015

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Reactions between hafnium powder and microcrystalline boron in a Na 2 B 4 O 7 ionic melt have been studied at temperatures from 600 to 850°C. The results demonstrate that nanoparticulate hafnium diboride forms starting at 750°C. According to electron microscopy data, the HfB 2 powder obtained at 850°C consists of nearly spherical particles 50-55 nm in diameter, which agrees with the equivalent particle diam eter ( 60 nm) evaluated from the specific surface area of the HfB 2 and with the crystallite size ( 55 nm) determined from X ray diffraction data.

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Section: Introductionmentioning

confidence: 63%

Preparation of hafnium diboride nanopowders in an anhydrous Na2B4O7 ionic melt

et al. 2015

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“…The XPS spectra exhibit not only lines typical of TiB 2 and ZrB 2 , but also weak lines corresponding to the metal and boron oxides and to elemental boron. 42,43 The influence of various factors on the synthesis of TiB 2 was thoroughly studied by diverse methods and approaches. 34, 42, 45, 47 ± 49 A detailed investigation of the synthesis of TiB 2 micropowders by carbothermal reduction of titanium and boron oxides at 1000 ± 1400 8C made it possible to monitor how the heating rate and the duration of keeping under isothermal conditions influence the degree of reaction completion and the phase and morphological compositions of reaction products.…”

Section: Introductionmentioning

confidence: 99%

Nanostructured titanium, zirconium and hafnium diborides: the synthesis, properties, size effects and stability

Andrievski¹

2015

Russ. Chem. Rev.

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“…Similarly to zirconium diboride, hafnium diboride can be prepared starting from the volatile borohydride decomposing upon heating following scheme (1) [1][2][3][4][5]. t M(BH 4 ) 4 → MB 2 + B 2 H 6 + 5H 2 (M = Zr, Hf).(1)Nanosized hafnium diboride can be also prepared via interaction of HfCl 4 with NaBH 4 at 600°С under inert [6,7] or via high-temperature carbothermal reduction of a mixture of HfO 2 and В 2 О 3 [8,9].We have earlier demonstrated the possibility of preparation of nanosized titanium and zirconium diborides upon interaction of titanium (zirconium) with boron in the Na 2 B 4 O 7 ionic melt [10][11][12]. Detailed study of this process is important in view of extending the knowledge on the influence of particles size on physico-chemical, mechanical, and other properties of various materials [13].…”

mentioning

confidence: 98%

“…We have earlier demonstrated the possibility of preparation of nanosized titanium and zirconium diborides upon interaction of titanium (zirconium) with boron in the Na 2 B 4 O 7 ionic melt [10][11][12]. Detailed study of this process is important in view of extending the knowledge on the influence of particles size on physico-chemical, mechanical, and other properties of various materials [13].…”

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confidence: 99%

Special features of preparation of nanosized hafnium diboride of different dispersity

et al. 2015

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X-ray diffraction analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, and elemental analysis have been applied to study the products of interaction of powder hafnium with fine-crystalline boron in the Na 2 B 4 O 7 ionic melt at 600-850°C and of HfCl 4 with NaBH 4 at 300-700°C.Keywords: hafnium diboride, nanosized particle, ionic melt, sodium tetraborate, sodium borohydride, hafnium tetrachloride Nanosized hafnium diboride is a typical nanosized boride of a group IV metal. Similarly to zirconium diboride, hafnium diboride can be prepared starting from the volatile borohydride decomposing upon heating following scheme (1) [1][2][3][4][5]. t M(BH 4 ) 4 → MB 2 + B 2 H 6 + 5H 2 (M = Zr, Hf).(1)Nanosized hafnium diboride can be also prepared via interaction of HfCl 4 with NaBH 4 at 600°С under inert [6,7] or via high-temperature carbothermal reduction of a mixture of HfO 2 and В 2 О 3 [8,9].We have earlier demonstrated the possibility of preparation of nanosized titanium and zirconium diborides upon interaction of titanium (zirconium) with boron in the Na 2 B 4 O 7 ionic melt [10][11][12]. Detailed study of this process is important in view of extending the knowledge on the influence of particles size on physico-chemical, mechanical, and other properties of various materials [13].In this work we studied two routes to prepare nanosized HfB 2 : via interaction of boron and hafnium powders in Na 2 B 4 O 7 ionic melt at 600-850°С (a) and via reaction of HfCl 4 with NaBH 4 at 300-700°С (b). In the latter case, in contrast to Ref.[6], initial heating of the reaction mixture was conducted in vacuum (0.133 Pa) rather than in an inert atmosphere. Table 1 show the conditions and the outcomes of interaction of equimolar amounts of powders of hafnium (0.83 g, 0.0046 mol) and boron (0.1 g, 0.0092 mol) in the presence of excess of Na 2 B 4 O 7 at 600-850°С. The results revealed that hafnium diboride was formed at ≥750°С, above the tetraborate melting point. The composition of hafnium diboride isolated from the reaction mixture (route a) as determined by chemical analysis and X-ray energy dispersive analysis was of HfB 2.02-2.03. Figures 1 and 2 andAccording to X-ray diffraction studies (Fig. 1), hafnium diboride formed crystals of hexagonal system, the lattice parameters being listed in Table 1; they well coincided with the reference data (a 0 = 0.3142 and c 0 = 0.3477 nm [14]).Analysis of the diffraction peaks in the range of 2θ = 15°-110° using the Scherrer equation (2) revealed that the coherent scattering area of HfB 2 D hkl was of ≈55 nm. D hkl = kλ/β hkl cos θ hkl .(2)In Eq.(2), k stands for anisotropy parameter taken equal to 0.9, λ is the X-ray radiation wavelength [λ(CuK α ) = 1.54178 Å], θ is diffraction angle, and β is half-width of the diffraction peak (rad).According to the scanning electron microscopy data, particles of the HfB 2 were of 50-55 nm (Fig. 2).

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Preparation of titanium diboride nanopowders of different particle sizes

Cited by 8 publications

References 11 publications

Preparation of hafnium diboride nanopowders in an anhydrous Na2B4O7 ionic melt

Preparation of hafnium diboride nanopowders in an anhydrous Na2B4O7 ionic melt

Nanostructured titanium, zirconium and hafnium diborides: the synthesis, properties, size effects and stability

Special features of preparation of nanosized hafnium diboride of different dispersity

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