Mechanism of formation of nanocrystalline particles with core-shell structure based on titanium oxynitrides with nickel in the process of plasma-chemical synthesis of TiNi in a low-temperature nitrogen plasma

Avdeeva, Yu. A.; Luzhkova, I.V.; Ermakov, A.N.

doi:10.17586/2220-8054-2022-13-2-212-219

Cited by 2 publications

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“…1), since this temperature is the minimum when plasma-chemical synthesis is carried out in low-temperature nitrogen plasma (4000 -6000 • C) with subsequent recondensation. On passing this temperature, in accordance with [5], Mo and Ti are presented simultaneously in the gaseous and liquid state, while C and Co are in the gaseous form, and TiN is in the liquid form. As the second temperature barrier, corresponding to the melting temperature of titanium nitride TiN (2930 • C [20]), is approached, it can be assumed that titanium carbonitride, in which the nitrogen content significantly Based on the patterns of formation of solid solutions used in the plasma-chemical synthesis of elements, it can be said that after a single recondensation (Table 2, Nos.…”

Section: Resultsmentioning

confidence: 54%

“…As previous studies show, the use of plasma-chemical synthesis for the recondensation of microcrystalline materials, such as titanium nickelide [5] or mechanical mixtures based on TiC [6], VC, VN [7] with metallic nickel, allows the formation of "core-shell" structures. A refractory compound based on elements of IV-VIA subgroups of the Periodic Table acts as the core, and the peripheral shell is presented in the form of Ni of cubic modification.…”

Section: Introductionmentioning

confidence: 99%

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Plasma-chemical synthesis of nanocrystalline "core-shell" structures TiN-Mo-Co

Avdeeva¹,

Luzhkova²,

Мурзакаев³

et al. 2023

Nanosystems: Phys. Chem. Math.

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In this work, the possibilities of formation of nanocrystalline powders based on titanium nitride with participation of Mo and Co under conditions of plasma-chemical synthesis have been studied. Synthesis was performed according to the plasma recondensation scheme using low-temperature nitrogen plasma. All the obtained highly dispersed powders were certified by X-ray diffraction and scanning electron microscopy. The characteristics of the disperse composition of the recondensed TiN-Mo-Co products were determined by the calculation based on the pycnometric density and specific surface area data. The possibility of formation of a "core-shell" structure was confirmed using chemical methods by etching ultraand nanodispersed powders in solutions of dilute HCl to remove the cobalt shell and concentrated hydrogen peroxide H 2 O 2 to neutralize metallic Mo. Based on the information about "quasi-equilibrium state" of the products of plasma-chemical synthesis in a low-temperature gas plasma, a chemical model for the formation of nanocrystalline particles is proposed. KEYWORDS core-shell structure, titanium nitride, plasma-chemical synthesis, temperature barrier, phase formation ACKNOWLEDGEMENTS The authors are grateful to Dr. E. K. Dobrinsky, Ph. D., leading researcher of SSC RF JSC "GNIIChTEOS" for help in carrying out the plasma-chemical synthesis. The work was carried out in accordance with the state assignment for the Institute of Solid State Chemistry of the Ural Branch of the Russian Academy of Sciences (theme No 0397-2019-0003 "New functional materials for promising technologies: synthesis, properties, spectroscopy and computer simulation").

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Section: Resultsmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Plasma-chemical synthesis of nanocrystalline "core-shell" structures TiN-Mo-Co

Avdeeva¹,

Luzhkova²,

Мурзакаев³

et al. 2023

Nanosystems: Phys. Chem. Math.

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Plasma-chemical synthesis of highly dispersed core–shell structures from a mechanical mixture of titanium carbide and titanium nickelide

Avdeeva,

Luzhkova,

Murzakaev

et al. 2024

Izv. VUZ. Poroshk. Met.

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In this paper, we studied the formation of ultrafine and nanocrystalline core–shell structures based on refractory compounds of titanium with nickel during plasma-chemical synthesis of a mechanical mixture of TiC and TiNi in a low-temperature nitrogen plasma. Cooling took place in an intensely swirling nitrogen flow in a quenching chamber. The derived products were separated in a vortex-type cyclone and a bag-type fabric filter. After processing, the products were subjected to encapsulation aimed at reducing the pyrophoricity for long-term storage of the resulting finely dispersed powders under normal conditions. X-ray diffraction and high-resolution transmission electron microscopy were used to study the resulting powder products of plasma-chemical synthesis, and density measurements were conducted. Additionally, to define the average particle size more accurately, the specific surface was measured using the BET method. The instrumental research revealed the presence of ultra- and nanodispersed particles with a core–shell structure in the powder products. These particles included titanium carbide-nitride compounds as a refractory core and metallic nickel as a metallic shell. In addition, the presence of complex titanium-nickel nitride Ti0.7Ni0.3N was recorded. According to direct measurements, the average particle size of the nanocrystalline fraction is 18.9 ± 0.2 nm. The obtained research results enabled us to develop a chemical model of crystallization of TiCxNy–Ni core–shell structures, which is implemented in a hardening chamber at a crystallization rate of 105 °С/s. To fabricate the model, we used the reference data on the boiling and crystallization temperatures of the elements and compounds being a part of highly dispersed compositions and recorded by X-ray diffraction, as well as the ΔG(t) dependences for TiC and TiN.

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Mechanism of formation of nanocrystalline particles with core-shell structure based on titanium oxynitrides with nickel in the process of plasma-chemical synthesis of TiNi in a low-temperature nitrogen plasma

Cited by 2 publications

References 0 publications

Plasma-chemical synthesis of nanocrystalline "core-shell" structures TiN-Mo-Co

Plasma-chemical synthesis of nanocrystalline "core-shell" structures TiN-Mo-Co

Plasma-chemical synthesis of highly dispersed core–shell structures from a mechanical mixture of titanium carbide and titanium nickelide

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