Synthesis of carbide solid solution with multiple components using elemental powder

Lun, Huilin; Zeng, Yi; Xiong, Xiang; Ye, Ziming; Qian, Tianxiao; Sun, Wei; Wang, Yalei; Chen, Zhaoke

doi:10.1016/j.apt.2019.10.019

Cited by 9 publications

(12 citation statements)

References 12 publications

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“…6,7 Several studies on the synthesis, densification, and microstructure of HEC ceramics have recently been reported. [6][7][8][9][10][11][12][13][14][15][16][17] HEC powders have been synthesized from commercial carbide powders by heating to form SS, 7 carbothermal reduction (CTR) of oxides followed by SS formation, 8,9 liquid precursors, 10 and reaction of elemental metals with carbon sources. 11 Significant particle growth occurred during the synthesis due to the high temperatures required for SS formation, which suppressed the densification of the resulting HEC ceramics.…”

Section: Introductionmentioning

confidence: 99%

Strength of single‐phase high‐entropy carbide ceramics up to 2300°C

et al. 2020

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The mechanical properties of single-phase (Hf,Zr,Ti,Ta,Nb)C high-entropy carbide (HEC) ceramics were investigated. Ceramics with relative density >99% and an average grain size of 0.9 ± 0.3 µm were produced by a two-step process that involved carbothermal reduction at 1600°C and hot pressing at 1900°C. At room temperature, Vickers hardness was 25.0 ± 1.0 GPa at a load of 4.9 N, Young's modulus was 450 GPa, chevron notch fracture toughness was 3.5 ± 0.3 MPa•m 1/2 , and four-point flexural strength was 421 ± 27 MPa. With increasing temperature, flexural strength stayed above ~400 MPa up to 1800°C, then decreased nearly linearly to 318 ± 21 MPa at 2000°C and to 93 ± 10 MPa at 2300°C. No significant changes in relative density or average grain size were noted after testing at elevated temperatures. The degradation of flexural strength above 1800°C was attributed to a decrease in dislocation density that was accompanied by an increase in dislocation motion. These are the first reported flexural strengths of HEC ceramics at elevated temperatures. K E Y W O R D S dislocation, high-entropy carbides, high-temperature flexural strength, mechanical properties, microstructure How to cite this article: Feng L, Chen W-T, Fahrenholtz WG, Hilmas GE. Strength of single-phase high-entropy carbide ceramics up to 2300°C.

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Section: Introductionmentioning

confidence: 99%

Strength of single‐phase high‐entropy carbide ceramics up to 2300°C

et al. 2020

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“…A relative dense ceramic phase was clearly visible in the cross‐sectional SEM image as depicted in Figure 1A. The as‐fabricated carbide has a density of 8.65 g cm −3 , and a relative density of up to 93% of the theoretical density (ie, 9.28 g cm −3 ) 21 . The inhomogeneous distribution of the metal element in the grains can be observed by EPMA; meanwhile, a compositionally gradient distribution in carbide was constructed by such elemental inhomogeneity.…”

Section: Resultsmentioning

confidence: 99%

“…The theoretical density of the carbide was calculated from the mass of the atoms in a unit cell and the lattice parameters measured from the XRD data. In order to get accurate data, pure multicomponent carbide powder with identical stoichiometric ratio was fabricated by free pressureless spark plasma sintering at 1600°C for 15 minutes 21 . And then XRD patterns were obtained at a scanning rate of 0.5°/min from 5° to 90°.…”

Section: Methodsmentioning

confidence: 99%

“…In order to get accurate data, pure multicomponent carbide powder with identical stoichiometric ratio was fabricated by free pressureless spark plasma sintering at 1600°C for 15 minutes. 21 And then XRD patterns were obtained at a scanning rate of 0.5°/min from 5° to 90°. The Rietveld refinement on the XRD patterns was carried out using the general structure analysis system (GSAS) software.…”

Section: Characterizationmentioning

confidence: 99%

“…The as-fabricated carbide has a density of 8.65 g cm −3 , and a relative density of up to 93% of the theoretical density (ie, 9.28 g cm −3 ). 21 The inhomogeneous distribution of the metal element in the grains can be observed by EPMA; meanwhile, a compositionally gradient distribution in carbide was constructed by such elemental inhomogeneity. As shown in Figure 1B, the closer the ceramic-carbon interface, the higher the content of Hf, while the content of Ti adjacent to the interface was lower than that in the central part of the ceramic phase.…”

Section: Microstructure and Constituents Of The Multicomponent Carbidementioning

confidence: 99%

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New insight into the formation and oxygen barrier mechanism of carbonaceous oxide interlayer in a multicomponent carbide

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Xiong

et al. 2020

J Am Ceram Soc

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Early transition metal carbides (TMCs), possessing simple metallic structures in which small carbon atoms occupy the interstitial voids of densely packed metallic lattice, merge the advantages of covalent solids, ionic crystals, and transition metals. As a result, TMCs often demonstrate extremely high melting points, considerable hardness. and excellent electric and thermal conductivity. 1 The unique combination of these desirable properties makes them a kind of promising material for a wide range of applications including hydrogen evolution electrocatalysts, 2,3 high-temperature solar absorber, 4 energy storage devices, and extreme environment applications, 5-7. Particularly, TMCs, such HfC, ZrC, TiC, and TaC, having the requisite refractoriness to withstand ultra-high temperatures and pronounced resistance to oxidation simultaneously are well suited for oxidizing environments at temperatures exceeding 2000°C. Generally, the oxidation resistance of TMCs is largely attributed to a carbonaceous oxide interlayer (eg, Hf-O-C, Zr-O-C, and Ta-O-C), located at the interface between the external oxide layer and internal carbide (eg, HfC, ZrC, and

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A New Sight on the Influence of Molten Salt in the Preparation of (Ta, Nb, Ti) C Nanopowder

Song,

Chen,

Chen

et al. 2024

Adv Eng Mater

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The molten salt method is an effective approach for obtaining multi‐component carbide nano‐powders at low temperatures. However, the presence of impurities limits its application in the lower‐temperature domains. To address this issue, (Ta, Nb, Ti) C nano‐powders are fabricated by the molten salt method at 1100‐1400°C and the dual route synthesis mechanism is revealed. Results indicate that the synthesis temperature of pure (Ta, Nb, Ti) C nano‐powders can be decreased with the addition of molten salt, which is determined by the formation and decomposition of the intermediates. During the synthesis process, the molten salt can provide liquid‐phase environment for the combination reaction between metal powders and carbon, facilitating the formation of homogeneous and nano‐sized powders. Meanwhile, the molten salt reacts with impurities to generate intermediates including KTaO3 and K1.04Ti8O16 at low temperatures, which subsequently form carbides through thermal reduction. This transformation can decrease the energy barrier of the synthesis process.This article is protected by copyright. All rights reserved.

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Synthesis of carbide solid solution with multiple components using elemental powder

Cited by 9 publications

References 12 publications

Strength of single‐phase high‐entropy carbide ceramics up to 2300°C

Strength of single‐phase high‐entropy carbide ceramics up to 2300°C

New insight into the formation and oxygen barrier mechanism of carbonaceous oxide interlayer in a multicomponent carbide

A New Sight on the Influence of Molten Salt in the Preparation of (Ta, Nb, Ti) C Nanopowder

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