boron carbide nanocrystalline
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boron carbide nanocrystalline

Thermal expansion of nanocrystalline boron carbide ...

Jul 01, 2012  Fig. 1 shows the room temperature (298 K) XRD patterns of the nanocrystalline and microcrystalline boron carbides.It is observed from the XRD patterns that boron carbide crystallises in a rhombohedral crystal structure. The average crystallite size of boron carbide prepared in this study by gel-pyrolysis method is 55 nm (designated as N-B 4 C) and that of boron carbide prepared by

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Synthesis of Nanocrystalline Boron Carbide via a ...

Dec 16, 2004  Nanocrystalline boron carbide (B 4 C) was synthesized via a solvothermal reduction of carbon tetrachloride using metallic lithium as reductant in the presence of amorphous boron powder at 600°C in an autoclave. The X-ray diffraction pattern of the product powder was indexed to the hexagonal B 4 C phase, with lattice constants a=5.606 and c=12.089 Å. . The sample was also characterized by ...

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Synthesis of Nanocrystalline Boron Carbide by Direct ...

boron anhydride, followed by the reduction to elemental boron by carbon, and finally the reaction of this species withcarbon,yieldingboroncarbide.Thisreactionisefficient and pure boron carbide can be produced at temperatures above1400∘Candnormallyalongreactiontime(1hto5h) [2]. The reaction time and temperature, heating rate, and

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Synthesis of nanocrystalline boron carbide from boric acid ...

高达10%返现  Sep 27, 2011  A novel method, based on the combustion of boric acid–sucrose xerogel was developed to synthesize nanocrystalline boron carbide powder. This xerogel was pyrolyzed at 1273 K. Boron carbide was obtained by heating this precursor at 1823 K. The yield of boron carbide was improved by the use of a novel graphite crucible designed for this purpose.

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Boron-Containing Nanocrystalline Ceramic and Metal–Ceramic ...

Jan 01, 2018  Boron-containing nanocrystalline composites represent a wide class of materials with unique physical properties useful for many industrial applications. This chapter considers the three seemingly most important boron-containing nanocomposites: boron carbide-based nanomaterials, metallic alloys modified with layered boron nitride nanopowder, and ...

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Enhanced mechanical properties of nanocrystalline boron ...

Sep 11, 2012  The mechanical properties of structural ceramics are characterized by a high degree of fragility and brittleness. This study demonstrates that, contrary to expectation, their brittleness can be ...

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Fabrication of (a-nc) boron carbide thin films via ...

to the amorphous-nanocrystalline structure, the (a-nc) boron carbide film has a low roughness, which is advantageous for reducing the Rayleigh Taylor instability during the ablation process [20]. Inthiswork,amorphous-nanocrystalline(a-nc)boron carbide films were deposited using ortho-carborane as asingleprecursorbythermalCVD.Theeffectsofdeposi-

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Phys. Rev. Lett. 121, 145504 (2018) - Grain Boundary ...

Oct 04, 2018  Grain Boundary Sliding and Amorphization are Responsible for the Reverse Hall-Petch Relation in Superhard Nanocrystalline Boron Carbide Dezhou Guo, Shuangxi Song, Ruichun Luo, William A. Goddard, III, Mingwei Chen, Kolan Madhav Reddy, and Qi An Phys. Rev. Lett. 121, 145504 – Published 4 October 2018

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Synthesis of Nanocrystalline Boron Carbide via a ...

Dec 16, 2004  Nanocrystalline boron carbide (B 4 C) was synthesized via a solvothermal reduction of carbon tetrachloride using metallic lithium as reductant in the presence of amorphous boron powder at 600°C in an autoclave. The X-ray diffraction pattern of the product powder was indexed to the hexagonal B 4 C phase, with lattice constants a=5.606 and c=12.089 Å. . The sample was also characterized by ...

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Synthesis of Nanocrystalline Boron Carbide via a ...

Dec 16, 2004  Nanocrystalline boron carbide (B 4 C) was synthesized via a solvothermal reduction of carbon tetrachloride using metallic lithium as reductant in the presence of amorphous boron powder at 600°C in an autoclave. The X-ray diffraction pattern of the product powder was indexed to the hexagonal B 4 C phase, with lattice constants a=5.606 and c=12.089 Å. . The sample was also characterized by ...

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Synthesis of nanocrystalline boron carbide from boric acid ...

Sep 27, 2011  A novel method, based on the combustion of boric acid–sucrose xerogel was developed to synthesize nanocrystalline boron carbide powder. This xerogel was pyrolyzed at 1273 K. Boron carbide was obtained by heating this precursor at 1823 K. The yield of boron carbide was improved by the use of a novel graphite crucible designed for this purpose.

Read More
Synthesis of nanocrystalline boron carbide from boric acid ...

A novel method, based on the combustion of boric acid–sucrose xerogel was developed to synthesize nanocrystalline boron carbide powder. This xerogel was pyrolyzed at 1273 K. Boron carbide was obtained by heating this precursor at 1823 K. The yield of boron carbide was improved by the use of a novel graphite crucible designed for this purpose.

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Modeling and simulation of boron-doped nanocrystalline ...

Modeling and simulation of boron-doped nanocrystalline silicon carbide thin film by a field theory. Xiong L(1), Chen Y, Lee JD. Author information: (1)University of Florida, Gainesville, FL 32611, USA. This paper presents the application of a multiscale field theory in modeling and simulation of boron-doped nanocrystalline silicon carbide (B-SiC).

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Fabrication of (a-nc) boron carbide thin films via ...

to the amorphous-nanocrystalline structure, the (a-nc) boron carbide film has a low roughness, which is advantageous for reducing the Rayleigh Taylor instability during the ablation process [20]. Inthiswork,amorphous-nanocrystalline(a-nc)boron carbide films were deposited using ortho-carborane as asingleprecursorbythermalCVD.Theeffectsofdeposi-

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Synthesis of nanocrystalline boron carbide from boric acid ...

Synthesis of nanocrystalline boron carbide from boric acid-sucrose gel precursor

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Grain Boundary Sliding and Amorphization are Responsible ...

Grain Boundary Sliding and Amorphization are Responsible for the Reverse Hall-Petch Relation in Superhard Nanocrystalline Boron Carbide

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上海交通大学 - 材料科学与工程学院

10. K. M. Reddy et al, Enhanced mechanical properties of nanocrystalline boron carbide by nanoporosity and interface phases, Nature Communications 3, 1052 (2012) 出版著作: Kolan Madhav Reddy (Editor), Boron Carbide: Structure, Processing, Properties and Applications 121, 322 (2020) Nova Publishers, Inc. USA (ISBN: 978-1-53617-121-1)

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Surface Properties and Morphology of Boron Carbide ...

Boron carbide (B 4 C), due to its specific properties (high hardness, low density, high melting point, high elastic modulus, etc.) [1,2], has been widely used in many applications such as in polishing as an abrasive, in ball mills as a neutron absorber and as a neutron shield, and in boron neutron capture therapy (BNCT).In BNCT research, nuclear reactors or accelerators generate thermal ...

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Growth of boron doped hydrogenated nanocrystalline cubic ...

Boron doped nanocrystalline cubic silicon carbide (3C-SiC) films have been prepared by HW-CVD using silane (SiH4)/methane (CH4)/diborane (B2H6) gas mixture. The influence of boron doping on structural, optical, morphological and electrical properties

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Shear-Driven Chemical Decomposition of Boron Carbide ...

We report, for the first time, the observation of a shear-induced decomposition of boron carbide into B 50 C 2 and nanocrystalline graphite at pressures from 1.0 to -3.5 GPa. It is proved that shear under modest compression provides finer controllability and more effective initiation capability than either compression alone or compression under high temperature.

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Highly Stable Boron Carbide Based Nanocomposites ...

Dec 25, 2020  Mikeladze A, Tsagareishvili O, Chkhartishvili L, Chedia R, Darchiashvili M (2019) Production of titanium-containing metal-ceramic composites based on boron carbide in the nanocrystalline state. Adv Appl Ceram 118:196–208 CrossRef Google Scholar

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Boron diffusion in nanocrystalline 3C-SiC - NASA/ADS

The diffusion of boron in nanocrystalline silicon carbide (nc-SiC) films with a grain size of 4-7 nm is studied using a poly-Si boron source. Diffusion is found to be much faster than in monocrystalline SiC as it takes place within the grain boundary (GB) network. Drive-in temperatures of 900-1000 °C are suitable for creating shallow boron profiles up to 100 nm deep, while 1100 °C is ...

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Synthesis of Nanocrystalline Boron Carbide via a ...

Dec 16, 2004  Nanocrystalline boron carbide (B 4 C) was synthesized via a solvothermal reduction of carbon tetrachloride using metallic lithium as reductant in the presence of amorphous boron powder at 600°C in an autoclave. The X-ray diffraction pattern of the product powder was indexed to the hexagonal B 4 C phase, with lattice constants a=5.606 and c=12.089 Å. . The sample was also characterized by ...

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An Efficient Template Synthesis of Aligned Boron Carbide ...

Feb 02, 2000  Synthesis of Nanocrystalline Boron Carbide via a Solvothermal Reduction of CCl4 in the Presence of Amorphous Boron Powder. Journal of the American Ceramic Society 2005, 88 (1) , 225-227. DOI: 10.1111/j.1551-2916.2004.00023.x.

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Synthesis of nanocrystalline boron carbide from boric acid ...

A novel method, based on the combustion of boric acid–sucrose xerogel was developed to synthesize nanocrystalline boron carbide powder. This xerogel was pyrolyzed at 1273 K. Boron carbide was obtained by heating this precursor at 1823 K. The yield of boron carbide was improved by the use of a novel graphite crucible designed for this purpose.

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(PDF) Strong influence of boron doping on nanocrystalline ...

Strong influence of boron doping on nanocrystalline silicon-carbide formation by using photo-CVD technique. Journal of Non-Crystalline Solids, 2005. Oleg Shevaleevskiy. Shinsuke Miyajima. Makoto Konagai. Seung Myong. Seung Myong. Oleg Shevaleevskiy.

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Growth of boron doped hydrogenated nanocrystalline cubic ...

Boron doped nanocrystalline cubic silicon carbide (3C-SiC) films have been prepared by HW-CVD using silane (SiH4)/methane (CH4)/diborane (B2H6) gas mixture. The influence of boron doping on structural, optical, morphological and electrical properties

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Shear-induced phase transition of nanocrystalline ...

Nov 20, 2012  Disordered structures of boron nitride (BN), graphite, boron carbide (BC), and boron carbon nitride (BCN) systems are considered important precursor materials for synthesis of superhard phases in these systems. However, phase transformation of such materials can be achieved only at extreme pressure–temperature conditions, which is irrelevant to industrial applications.

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Toughening of Boron Carbide Composites with Hierarchical ...

Jan 05, 2020  To toughen boron carbide, past studies implemented toughening mechanisms such as crack deflection and bridging by reinforcement particles, whiskers, and fibers. Recent studies have demonstrated novel deformation mechanisms triggered in nanocrystalline B4C which can potentially enhance its fracture resistance by grain boundary sliding ...

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Wholesale Boron Carbide Nanoparticle,High Quality Carbide ...

Hot Tags : abrasive material B4C High Hardness Boron carbide nanocrystalline boron carbide submicron boron carbide. Read More. Synthetic superhard material B4C Boron Carbide Powders. Buy synthetic superhard material B4C Boron Carbide Powders, Size:50nm, 100nm, 500nm, 1-3um, 10-100um, Purity:99% Shape:cubic, high quality, low price and fast ...

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Boron Carbide: Structure, Processing, Properties and ...

Chapter 5. Mechanical Properties and Deformation Mechanism in Nanocrystalline Boron Carbide (Rajamallu Karre, Qi An and Kolan Madhav Reddy, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China, and others) Chapter 6. Sliding Wear Properties of Boron Carbide ...

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Boron nitride │ Technical ceramics

Binderless nanocrystalline cubic boron nitride (BNNC) BNNC is a newly developed cutting material for materials that are difficult to machine. Compared to the established CBN cutting materials, it has an even higher degree of hardness and even better temperature resistance.

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Highly Stable Boron Carbide Based Nanocomposites ...

Dec 25, 2020  Mikeladze A, Tsagareishvili O, Chkhartishvili L, Chedia R, Darchiashvili M (2019) Production of titanium-containing metal-ceramic composites based on boron carbide in the nanocrystalline state. Adv Appl Ceram 118:196–208 CrossRef Google Scholar

Read More
Shear-Driven Chemical Decomposition of Boron Carbide ...

We report, for the first time, the observation of a shear-induced decomposition of boron carbide into B 50 C 2 and nanocrystalline graphite at pressures from 1.0 to -3.5 GPa. It is proved that shear under modest compression provides finer controllability and more effective initiation capability than either compression alone or compression under high temperature.

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13C NMR Spectroscopy of Amorphous Hydrogenated Carbon and ...

We suggest the two sharp lines at 135 and 170 ppm could be due to carbon atoms in boron-containing aromatic rings, and the broader line at 15 ppm as due to carbon atoms in boron carbide icosahedra. These lines provide evidence of nanocrystalline structure imbedded in an amorphous hydrogenated boron carbide matrix.

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Titanium diboride - Wikipedia

Titanium diboride (TiB 2) is an extremely hard ceramic which has excellent heat conductivity, oxidation stability and wear resistance. TiB 2 is also a reasonable electrical conductor, so it can be used as a cathode material in aluminium smelting and can be shaped by electrical discharge machining .

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