A Review on Boron Carbide

Thévenot, F.

doi:10.4028/www.scientific.net/kem.56-57.59

Cited by 98 publications

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“…A large variety of preparation methods for boron carbide powder and bulk samples yield a wide range of variation of mechanical properties such as hardness or density. 32 B 4 C coatings in the homogeneity range mentioned above solidify in a rhombohedral structure at short range for substrate temperatures below 900 C during deposition. For substrate temperature above 950 C, a variety of crystalline phases occur.…”

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confidence: 99%

“…% carbon) in the compound of boron carbide and its comprehensive phase diagram are presented in Ref. 32. A large variety of preparation methods for boron carbide powder and bulk samples yield a wide range of variation of mechanical properties such as hardness or density.…”

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confidence: 99%

“…33,34 X-Ray Diffraction (XRD)-studies on crystalline B 4 C show the unit cell consisting of a rhombohedron with B 12 icosahedra at each corner. 32,35 The space group of B 4 C is R 3m(166). 32,35 There are two types of spatial arrangements of the B 12 icosahedral clusters called a-and b-type structure.…”

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“…32,35 The space group of B 4 C is R 3m(166). 32,35 There are two types of spatial arrangements of the B 12 icosahedral clusters called a-and b-type structure. 36 B 4 C possesses electronic properties of a semiconductor.…”

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“…36 B 4 C possesses electronic properties of a semiconductor. 32 In a first attempt, RF-sputtering modes were used to fabricate B 4 C coatings for optical applications. 33,37,38 DC-sputtering modes were also investigated for coatings of cutting tools 39 as well as for 10 B 4 C coatings on large areas.…”

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Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Nowak

Störmer

Becker

et al. 2015

Journal of Applied Physics

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Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality He and the associated tremendous increase of its price, the supply of large neutron detection systems with 3 He becomes unaffordable. Alternative neutron detection concepts, therefore, have been invented based on solid 10 B converters. These concepts require development in thin film deposition technique regarding high adhesion, thickness uniformity and chemical purity of the converter coating on large area substrates. We report on the sputter deposition of highly uniform large-area 10 B 4 C coatings of up to 2 lm thickness with a thickness deviation below 4% using the Helmholtz-Zentrum Geesthacht large area sputtering system. The 10 B 4 C coatings are x-ray amorphous and highly adhesive to the substrate. Material analysis by means of X-ray-Photoelectron Spectroscopy, Secondary-Ion-Mass-Spectrometry, and RutherfordBack-Scattering (RBS) revealed low impurities concentration in the coatings. The isotope composition determined by Secondary-Ion-Mass-Spectrometry, RBS, and inelastic nuclear reaction analysis of the converter coatings evidences almost identical 10 B isotope contents in the sputter target and in the deposited coating. Neutron conversion and detection test measurements with variable irradiation geometry of the converter coating demonstrate an average relative quantum efficiency ranging from 65% to 90% for cold neutrons as compared to a black 3 He-monitor. Thus, these converter coatings contribute to the development of 3 He-free prototype detectors based on neutron grazing incidence. Transferring the developed coating process to an industrial scale sputtering system can make alternative 3 He-free converter elements available for large area neutron detection systems.

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Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Nowak

Störmer

Becker

et al. 2015

Journal of Applied Physics

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Approaching Carbon Nanotube Reinforcing Limit in B₄C Matrix Composites Produced by Chemical Vapor Infiltration

Yang

et al. 2013

Adv Eng Mater

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Boron carbide (nominally B 4 C) is one of the most useful nonoxide ceramics in modern engineering because of its unique combination of low density (2.5 g cm À3 ), high hardness (the third hardest material at room temperature), high melting point (>2400°C), small thermal expansion coefficient (5.73 Â 10 À6 K À1 ), high resistance to chemical attacks, effectiveness against low-velocity threats, and large neutron absorption cross-section. [1,2] These characteristics make boron carbide attractive for numerous important applications including lightweight body armors, abrasive wear-resistant materials, and neutron detectors. [3,4] However, its extreme sensitivity to brittle fracture and the difficulty in fabricating dense material impair the use of boron carbide in practical applications. [5,6] Owing to their exceptional stiffness and strength, [7][8][9] carbon nanotubes (CNTs) have long been considered to be an ideal reinforcement for light-weight, high-strength, and high-temperature-resistant ceramic matrix composites (CMCs). [10][11][12] However, many studies on the CNT-reinforced CMCs, such as CNT/SiC, [13] CNT/Al 2 O 3 , [14,15] CNT/Si 3 N 4 , [16] CNT/SiO 2 , [17] and CNT/B 4 C, [18][19][20] have not been as successful as expected. This is because the CNT-reinforced CMCs were generally fabricated by a dispersion-mixing-sintering strategy, which encounters several insuperable manufacturing problems, such as poor dispersion of CNTs in the matrix, damage of nanotubes during processing, and weak CNT/matrix interfaces, [11,21] resulting in undesirable microstructures and thus much-lower-than-expected mechanical properties. To overcome these roadblocks in manufacturing CNT-reinforced CMCs, we recently used a chemical vapor infiltration (CVI) method, a technique that allows the formation of very high melting point materials (e.g. carbides, silicides, borides, nitrides, and oxides) in porous substrates at relatively low temperature, [22,23] to fabricate CNT/SiC composites by depositing SiC onto aligned multi-wall CNT sheets. [24] Using the CVI method, several of the fabrication steps such as dispersion, mixing, and sintering, are no longer necessary, and therefore most of the manufacturing problems previously encountered in the fabrication of CNT reinforced CMCs can be readily overcome. As a result, the CVI-fabricated CNT/SiC composites have a strongly bonded tube/matrix interface and an amorphous, dense SiC matrix, enabling the composites to have fracture strength about an order of magnitude higher than the bulk SiC. [24] In the present study, we further extend the CVI technique to fabricate high-quality CNT/B 4 C composites by chemically infiltrating B 4 C into aligned multi-wall CNT sheets (CNTs have diameters ranging from 15 to 20 nm) at a low temperature of 1000°C. Amorphous and dense B 4 C coating was obtained in the CNT sheets. AFM based mechanical measurements on individual CNT/B 4 C composite nanowires show a fracture strength about 1-2 orders of magnitude higher than that of the high-temperature (>1800°C) sinte...

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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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A Review on Boron Carbide

Cited by 98 publications

References 0 publications

Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Approaching Carbon Nanotube Reinforcing Limit in B₄C Matrix Composites Produced by Chemical Vapor Infiltration

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

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A Review on Boron Carbide

Cited by 98 publications

References 0 publications

Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Approaching Carbon Nanotube Reinforcing Limit in B4C Matrix Composites Produced by Chemical Vapor Infiltration

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

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Approaching Carbon Nanotube Reinforcing Limit in B₄C Matrix Composites Produced by Chemical Vapor Infiltration

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