Microstructure and Thermoelectric Properties of Dense YB22C2N Samples Fabricated Through Spark Plasma Sintering

Berthebaud, David; Nishimura, Toshiyuki; Mori, Takao

doi:10.1007/s11664-011-1509-0

Cited by 10 publications

(4 citation statements)

References 10 publications

(11 reference statements)

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“…Incidentally with SPS it was previously found that the densities could be increased to ∼75% with spark plasma sintering (SPS) 33 or further to even 95% with additives in SPS. 35,38 For simply cold pressed "pure" Y 1−x B 28.5 C 4 the achieved density was a little higher than the "conventional" case and reached ∼65%.…”

Section: Methodsmentioning

confidence: 88%

The origin of the n-type behavior in rare earth borocarbide Y_1−xB_28.5C₄

et al. 2014

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Synthesis conditions, morphology, and thermoelectric properties of Y1-xB28.5C4 were investigated. Y1-xB28.5C4 is the compound with the lowest metal content in a series of homologous rare earth borocarbonitrides, which have been attracting interest as high temperature thermoelectric materials because they can embody the long-awaited counterpart to boron carbide, one of the few thermoelectric materials with a history of commercialization. It was revealed that the presence of boron carbide inclusions was the origin of the p-type behavior previously observed for Y1-xB28.5C4 in contrast to Y1-xB15.5CN and Y1-xB22C2N. In comparison with that of previous small flux-grown single crystals, a metal-poor composition of YB40C6 (Y0.71B28.5C4) in the synthesis successfully yielded sintered bulk Y1-xB28.5C4 samples apparently free of boron carbide inclusions. "Pure" Y1-xB28.5C4 was found to exhibit the same attractive n-type behavior as the other rare earth borocarbonitrides even though it is the most metal-poor compound among the series. Calculations of the electronic structure were carried out for Y1-xB28.5C4 as a representative of the series of homologous compounds and reveal a pseudo gap-like electronic density of states near the Fermi level mainly originating from the covalent borocarbonitride network.

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Section: Methodsmentioning

confidence: 88%

The origin of the n-type behavior in rare earth borocarbide Y_1−xB_28.5C₄

et al. 2014

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“…Titanium diboride (TiB 2 ) is compatible with B 4 C because B 4 C and TiB 2 form binary eutectic composites. Therefore, the TiB 2 phase would be suitable to improve the electrical and thermal conductivity of B 4 C. The electrical conductivity of the B 4 C-TiB 2 composites significantly increased with increasing TiB 2 content, [40][41][42][43][44][45][46] which will enable the potential use of composites as thermoelectrics in the future.…”

Section: Introductionmentioning

confidence: 99%

“…The compositions' behavior was evaluated. The samples were subjected to isostatic pressing [41][42][43] before sintering to improve the composite properties. This study describes the free sintering and reactive sintering of hot-pressed composites based on commercial boron carbide with boron and titanium additives.…”

Section: Introductionmentioning

confidence: 99%

Effect of Additives on the Reactive Sintering of Ti–B₄C Composites Consolidated by Hot Pressing and Pressureless Sintering

et al. 2022

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Composites based on boron carbide (B 4 C) have drawn attention due to their outstanding physical and chemical properties. Herein, the effect of adding boron, titanium, and both titanium and boron, on the B 4 C-based material, is investigated. In addition, the additives' influence on the temperature of composite synthesis and the whole sintering process is evaluated. The Ti-B 4 C composites are prepared by two different methods: pressureless sintering and hot pressing. The presence of Ti, B, and C as dominant additives in the sintered composites is confirmed by X-ray diffraction and scanning electron microscopy (SEM). The SEM examination reveals that TiB 2 particles formed during the composite process synthesis are distributed homogeneously in the B 4 C matrix. Mechanical properties, such as hardness, Young's modulus, and fracture toughness are tested, along with the composites' density and porosity. All the sintered samples, regardless of the incorporated additives, are characterized by high mechanical properties, reaching outstanding values in a few cases. The obtained results allow us to state that the usage of a boron and titanium mixture significantly improves the sintering process of composites due to the reactive sintering phenomenon occurring during the composites' preparation. The Ti-B 4 C composites are classified as ultrahigh-temperature ceramics materials.

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“…Rare earth borocarbonitrides, RB 22 C 2 N, RB 17 CN and RB 28.5 C 4 , were discovered to be the first boron icosahedra cluster containing compounds that exhibit intrinsic n-type thermoelectric materials [14,15]. Some of the recently discovered novel borides have been found not to be easy to obtain dense samples, and various studies to remedy this have been carried out; for example, mechanical grinding and sintering the sample through the spark plasma sintering (SPS) treatment with sintering aids such as metals, rare earth tetra brides and carbides [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and thermoelectric properties of Y x Al y B14 samples fabricated through the spark plasma sintering

Maruyama

Nishimura

Miyazaki

et al. 2014

Mater Renew Sustain Energy

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Excellent control in p-and n-type transport characteristics was previously obtained for the thermoelectric Y x Al y B 14 compounds through Al flux method. In this study, new attempts were made to reduce their grain sizes to obtain dense samples and to possibly lower the thermal conductivity. Introducing the reduction of grain sizes into Y x Al y B 14 samples was attempted by two methods; one was through mechanical grinding, and the other was by synthesizing Y x Al y B 14 via Y 0.56 B 14 (denoted as ''vYB-YAlB 14 ''). Mechanical grinding using ball milling with Si 3 N 4 pots and balls was found not to be an efficient way to decrease the grain size because of contamination of Si 3 N 4 . In contrast, vYB-YAlB 14 samples were successfully synthesized. Through the synthesis of Y 0.56 B 14 , the boron network structure was first formed. Afterward, Y x Al y B 14 was obtained by adding Al in the boron network structure through a heat treatment. Due to shorter heating time at lower temperature, the grain sizes were discovered to be smaller than that of Al flux method. The decrease of grain size was found to be beneficial for the densification of Y x Al y B 14 and the decrease of its thermal conductivity.

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Microstructure and Thermoelectric Properties of Dense YB22C2N Samples Fabricated Through Spark Plasma Sintering

Cited by 10 publications

References 10 publications

The origin of the n-type behavior in rare earth borocarbide Y_1−xB_28.5C₄

The origin of the n-type behavior in rare earth borocarbide Y_1−xB_28.5C₄

Effect of Additives on the Reactive Sintering of Ti–B₄C Composites Consolidated by Hot Pressing and Pressureless Sintering

Microstructure and thermoelectric properties of Y x Al y B14 samples fabricated through the spark plasma sintering

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Microstructure and Thermoelectric Properties of Dense YB22C2N Samples Fabricated Through Spark Plasma Sintering

Cited by 10 publications

References 10 publications

The origin of the n-type behavior in rare earth borocarbide Y1−xB28.5C4

The origin of the n-type behavior in rare earth borocarbide Y1−xB28.5C4

Effect of Additives on the Reactive Sintering of Ti–B4C Composites Consolidated by Hot Pressing and Pressureless Sintering

Microstructure and thermoelectric properties of Y x Al y B14 samples fabricated through the spark plasma sintering

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The origin of the n-type behavior in rare earth borocarbide Y_1−xB_28.5C₄

The origin of the n-type behavior in rare earth borocarbide Y_1−xB_28.5C₄

Effect of Additives on the Reactive Sintering of Ti–B₄C Composites Consolidated by Hot Pressing and Pressureless Sintering