Investigation on mechanochemical behavior of Al/Mg–B2O3–Nb system reactive mixtures to synthesize niobium diboride

Jafari, Morad; Tajizadegan, Hamid; Golabgir, Mohammad Hossein; Chami, Akbar; Torabi, Omid

doi:10.1016/j.ijrmhm.2014.10.017

Cited by 15 publications

(3 citation statements)

References 22 publications

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“…However, when the liquid magnesium contacts Nb 2 O 5 powder directly, it may be resulted in rapid, violent and explosive behavior. 10) Hence there is a research case of the reduction reaction induced slowly by mixing and molding powdered magnesium with niobium oxide. 11,12) However there is a risk as using explosive or relatively expensive magnesium powder.…”

Section: Introductionmentioning

confidence: 99%

Metallic Niobium Powder Reduced by Atmospheric Magnesium Gas with Niobium Pentoxide Powder

et al. 2021

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It was tried to find the optimal condition to prepare the metallic niobium powder with minimal oxygen content by atmospheric magnesiumgas reduction of niobium pentoxide (Nb 2 O 5 ) powder at 10731223 K, which are industrially moderate and low temperature ranges until maximally 80 h inside the chamber held under the argon circumstances of 110 kPa. Magnesium oxide of the by-product of the reduction, was dissolved and removed fully by dissolving in a 10% aqueous hydrochloric acid solution. The particle size of the niobium powder reduced for 20 h was slightly increased within the range of 200³600 nm according to increase of reduction temperatures. And such fine particles were further coarsened to near 1 µm by increase of reduction times until 80 h at 1173 K, which is thought to be the most suitable for magnesium-gas reduction to be applied in industry. The reduction time satisfied for a maximal reduction effect was found to be 60 hours as the oxygen content was then minimally saturated to about 0.42 wt.%. Furthermore, the hydrogen contamination due to acid leaching of 0.28 wt.% was fully removed by dehydrogenation, which was a heat treatment performed under vacuum at 827 K for 2 h; this resulted in the formation of metallic niobium powder.

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Section: Introductionmentioning

confidence: 99%

Metallic Niobium Powder Reduced by Atmospheric Magnesium Gas with Niobium Pentoxide Powder

et al. 2021

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“…A general rout towards metal boride nanocrytals had been developed by ionothermal process at a relatively mild temperature (500-900 °C) [14]. Torabi et al developed a mechanical-thermal approach to synthesize NbB 2 powder from Mg/B 2 O 3 /Nb powder mixture [15]. Herein, NbB 2 nanosheets were prepared from metal niobium and sodium borohydride via an iodine-assisted synthesis process at low temperature of 700 °C in a stainless steel autoclave.…”

Section: Introductionmentioning

confidence: 99%

Chemical Synthesis of Niobium Diboride Nanosheets by a Solid-State Reaction Route

Wang

Shen

Qin

et al. 2018

J. Superhard Mater.

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Chemical synthesis of niobium diboride nanosheets by a solid-state reaction routeA new process was developed to synthesize niobium diboride (NbB 2 ) nanosheets with the dimension of about 500 nm and thickness of about 10 nm by using metal niobium, iodine and sodium borohydride as starting materials in an stainless steel autoclave at 700 °C. Iodine was used to facilitate the exothermic reaction between metal niobium and sodium borohydride and the formation of NbB 2 . X-ray powder diffraction pattern indicated that the obtained product is hexagonal phase NbB 2 with the calculated lattice constants a = 110 Å and c = 3.2929 Å. The obtained product was also studied by thermogravimetric analysis. It had good oxidation resistance below 400 °C in air.

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“…Beyond the solvothermal synthesis method, Co 2 B was also synthesized by Kanomata et al [18] via the thermal method in 1997 and by Choi et al [19] via the thermal plasma method in 2014. Although many studies for synthesis of metal borides by the mechanochemical synthesis (MCS) method have been done [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], only one study was performed for synthesis of Co 2 B by Wang et al [37] published in 2012. By considering the gap in the literature, a newly developed mechanochemical synthesis protocol for the synthesis of Co 2 B nanoparticles was proposed.…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical synthesis and characterization of pure Co2B nanocrystals

2016

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Cobalt boride (Co 2 B) is a significant transition metal boride having a wide range of usage area due to its high oxidation, abrasion and corrosion resistance as well as its superior electrochemical, magnetic and anisotropic properties. In this study, pure Co 2 B nanocrystals were synthesized with Co, B 2 O 3 and Mg as starting materials via the mechanochemical synthesis (MCS) method by high-energy planetary ball mill in a hardened steel vial with hardened steel balls. All the experiments were conducted under Ar atmosphere at different rotational speeds and at 20 : 1-30 : 1-40 : 1 ball-to-powder ratios. Leaching of Co 2 B + MgO powder mixtures occurred after milling and purified with acetic acid and pure Co 2 B nanocrystals were obtained in solid form. The Co 2 Bs were characterized through X-ray diffraction, scanning electron microscopy, vibrating sample magnetometer, Brunauer-Emmett-Teller and specific density analyses, and effects of synthesis parameters on product properties were revealed. Surface areas of the powders synthesized at 40 : 1 ball-to-powder ratio at different rotational speeds were measured as 21.14, 40.36 and 52.33 m 2 g −1 , respectively. Crystallite sizes of Co 2 B nanocrystals were between 7.27 and 9.84 nm and their specific density varied between 7.61 and 7.78 g cm −3. It was determined that all samples were saturated and exhibited hysteresis and ferromagnetic behaviours, and saturation magnetization was between 35 and 50 emu g −1 .

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Investigation on mechanochemical behavior of Al/Mg–B2O3–Nb system reactive mixtures to synthesize niobium diboride

Cited by 15 publications

References 22 publications

Metallic Niobium Powder Reduced by Atmospheric Magnesium Gas with Niobium Pentoxide Powder

Metallic Niobium Powder Reduced by Atmospheric Magnesium Gas with Niobium Pentoxide Powder

Chemical Synthesis of Niobium Diboride Nanosheets by a Solid-State Reaction Route

Mechanochemical synthesis and characterization of pure Co2B nanocrystals

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