New Superhard Ternary Borides in Composite Materials

Zakhariev,

doi:10.5772/21651

Cited by 4 publications

(7 citation statements)

References 9 publications

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“…As-received carbides have an expected elastic modulus (young's modulus) of 640 GPa [20], this agrees with our measured value of 660 ± 20 GPa. Previously reported values for WCoB hardness vary, but include values from 23.4 GPa [11] to 45 GPa [19]. Our data falls within this range with data points as high as 45 GPa.…”

Section: Nanoindentation Hardnesssupporting

confidence: 72%

“…Boriding is widely used to improve material properties, and can be successfully implemented as a surface treatment for diamond deposition in an array of materials, including tungsten carbide [9,10]. Boriding is shown to result in higher hardness and improved durability when compared to other surface modifications, such as, carburizing or nitriding [11][12][13]. Transition metal borides (TiB 2 , ZrB 2 , Fe 2 B and Co 2 B) are good candidates for diamond deposition; they are stable, compatible with carbon, densely packed, and inhibit carbon diffusion [3,13].…”

Section: Introductionmentioning

confidence: 99%

“…These borides often include orthorhombic CoB and bodycentered tetragonal Co 2 B structures, among others. PECVD boriding of tungsten carbide can also form the less explored ternary borides (WCoB, W 2 CoB 2 and W 3 CoB 3 ) with reported hardness ranging from 23.4 GPa [11] to 45 GPa [19]. In the current work, we explore the formation of borides on tungsten carbide during PECVD using diborane and a range of substrate temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Johnston

Catledge

2016

Applied Surface Science

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Strengthening of cemented tungsten carbide by boriding is used to improve the wear resistance and lifetime of carbide tools; however, many conventional boriding techniques render the bulk carbide too brittle for extreme conditions, such as hard rock drilling. This research explored the variation in metal-boride phase formation during the microwave plasma enhanced chemical vapor deposition process at surface temperatures from 700 to 1100 °C. We showed several welladhered metal-boride surface layers consisting of WCoB, CoB and/or W 2 CoB 2 with average hardness from 23-27 GPa and average elastic modulus of 600-730 GPa. The metal-boride interlayer was shown to be an effective diffusion barrier against elemental cobalt; migration of elemental cobalt to the surface of the interlayer was significantly reduced. A combination of glancing angle x-ray diffraction, electron dispersive spectroscopy, nanoindentation and scratch testing was used to evaluate the surface composition and material properties. An evaluation of the material properties shows that plasma enhanced chemical vapor deposited borides formed at substrate temperatures of 800 °C, 850 °C, 900 °C and 1000 °C strengthen the material by increasing the hardness and elastic modulus of cemented tungsten carbide. Additionally, these boride surface layers may offer potential for adhesion of ultra-hard carbon coatings.

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Section: Nanoindentation Hardnesssupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Johnston

Catledge

2016

Applied Surface Science

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“…The temperature and velocity average of particles in flight during arc wire spraying have been reported, to reach temperatures of 2200 ∘ C and 138 m/s, respectively [28]. Thus, the boron carbides contained in the coating did not dissolve in the amorphous phase due to the average temperature during thermal spraying which was lower than the melt temperature of boron carbide B 2 C 13 (2447 ∘ C) [29]. Likewise, the tungsten on the powder precursor did not dissolve during spraying because melting temperature of tungsten is 3400 ∘ C [30].…”

Section: Coating Characterizationmentioning

confidence: 99%

Microstructural Characterization and Wear Properties of Fe-Based Amorphous-Crystalline Coating Deposited by Twin Wire Arc Spraying

Morquecho

Campa-Castilla

Leyva‐Porras

et al. 2014

Advances in Materials Science and Engineering

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Twin wire arc spraying (TWAS) was used to produce an amorphous crystalline Fe-based coating on AISI 1018 steel substrate using a commercial powder (140MXC) in order to improve microhardness and wear properties. The microstructures of coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) as well as the powder precursor. Analysis in the coating showed the formation of an amorphous matrix with boron and tungsten carbides randomly dispersed. At high amplifications were identified boron carbides at interface boron carbide/amorphous matrix by TEM. This kind of carbides growth can be attributed to partial crystallization by heterogeneous nucleation. These interfaces have not been reported in the literature by thermal spraying process. The measurements of average microhardness on amorphous matrix and boron carbides were 9.1 and 23.85 GPa, respectively. By contrast, the microhardness values of unmelted boron carbide in the amorphous phase were higher than in the substrate, approaching 2.14 GPa. The relative wear resistance of coating was 5.6 times that of substrate. These results indicate that the twin wire arc spraying is a promising technique to prepare amorphous crystalline coatings.

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“…The reason is their extraordinary properties: they can, e.g. present superhardness [1,2], have very high melting points and thermal conductivities [3,4], improve oxidation and corrosion resistance [5,6] and can be exceptionally efficient electrocatalysts [7,8]. They also represent promises for future technologies or fundamental research, like magnetocaloric effects [9], thermoelectricity [10], complex magnetism [11] or heavy fermion superconductivity [12].…”

Section: Introductionmentioning

confidence: 99%

Peculiar properties of UMB₄ (M = V, Cr, Mo, W) uranium borides

Gonçalves

Dias

Carvalho

et al. 2019

Advances in Applied Ceramics

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UMB 4 (M = V, Cr, Fe, Co, Mo, W, Re, Os) materials prepared by arc-melting have UMB 4 as the main phase, with (V, Cr, Fe, Co) crystallising in the YCrB 4 structure type, while (Mo, W, Re, Os) adopt the ThMoB 4 -type. For M = V, Cr, Mo, W the magnetic susceptibility is low and only weakly temperature dependent, but higher than α-U, which can be ascribed to a higher density of states at the Fermi level. Heat capacity results point to a very high Debye temperature for both structures, which is associated with very high lattice stiffness of the boron network. However, for W and Mo the boron vibrations are accompanied by lowenergy Einstein modes coming from vibrations of the atoms inside the boron cages that could lead to superconductivity. The electronic structure of UMB 4 is influenced by a strong 5f-d hybridization and by the B-2p states, which explains the observed weak Pauli paramagnetism.

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New Superhard Ternary Borides in Composite Materials

Cited by 4 publications

References 9 publications

Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Microstructural Characterization and Wear Properties of Fe-Based Amorphous-Crystalline Coating Deposited by Twin Wire Arc Spraying

Peculiar properties of UMB₄ (M = V, Cr, Mo, W) uranium borides

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New Superhard Ternary Borides in Composite Materials

Cited by 4 publications

References 9 publications

Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Microstructural Characterization and Wear Properties of Fe-Based Amorphous-Crystalline Coating Deposited by Twin Wire Arc Spraying

Peculiar properties of UMB4 (M = V, Cr, Mo, W) uranium borides

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Product

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Peculiar properties of UMB₄ (M = V, Cr, Mo, W) uranium borides