Sparking plasma sintering of nanometric tungsten carbide

Zhao, Jinfeng; Holland, Troy B.; Unuvar, C.; Munir, Zuhair A.

doi:10.1016/j.ijrmhm.2008.06.004

Cited by 104 publications

(52 citation statements)

References 19 publications

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“…A higher hardness of 24.15 GPa was determined for sample C. After treatment by HIP, the hardness of samples D and E was greater than 26.00 GPa. The highest hardness of 26.77 GPa obtained in sample D is close to or higher than those of reported binderless WC, i.e., Hv 1 = 27.05 GPa, 6) Hv 10 = 23.14 GPa, 17) Hv 10 = 25.40 GPa. 18) It is worthwhile to note that the hardness of the sample depends on the JCS-Japan applied indention load; the higher the applied indention load, the lower the hardness.…”

Section: Mechanical Properties Analysissupporting

confidence: 65%

Binderless sub-micron WC consolidated by hot pressing and treated by hot isostatic pressing

Wang

Zhu

Jiang

et al. 2014

J. Ceram. Soc. Japan

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Highly dense binderless WC was obtained by hot press sintering (HP) and then treated by hot isostatic pressing (HIP). Compositional and phase analyses of the products were carried out using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The mechanical properties were evaluated, and the location of the inhibitors was studied by transmission electron microscopy (TEM). The sub-micron (0.53¯m) powders of WC (doped with 0.33 wt % VC and 0.54 wt % Cr 3 C 2 ) were HP sintered at 1800, 1900, and 2000°C. WC with a relative density of 97.9% and a grain size of approximately 0.73¯m was obtained after sintering at 2000°C for 30 min under a pressure of 28 MPa. The Vickers hardness and fracture toughness were 24.15 « 0.33 GPa and 4.40 « 0.10 MPa·m 1/2 , respectively. After treatment by HIP at 1750°C for 120 min under a pressure of 150 MPa, the relative density of the samples was increased to 99.4%, the hardness was over 26.00 GPa, and the grain size was 0.750.81¯m. The grain growth inhibitors were also characterised by TEM and energy dispersive X-ray spectroscopy (EDX); the results show that the grain growth was effectively suppressed by the inhibitors of VC and Cr 3 C 2 as a result of the segregation of the inhibitors at the grain boundaries.

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Section: Mechanical Properties Analysissupporting

confidence: 65%

Binderless sub-micron WC consolidated by hot pressing and treated by hot isostatic pressing

Wang

Zhu

Jiang

et al. 2014

J. Ceram. Soc. Japan

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“…This is very encouraging considering that tungsten is much less expensive than rhenium. Note also that the hardness of WB 4 is considerably higher than that of OsB 2 and RuB 2 (15) and at least 1.5 times that of the traditional material used for machine tools, tungsten carbide (38)(39)(40). The high hardness of WB 4 may be associated with its unique crystal structure consisting of a three-dimensional network of boron with tungsten atoms sitting in the voids (Fig.…”

Section: Resultsmentioning

confidence: 97%

Tungsten tetraboride, an inexpensive superhard material

Mohammadi

Lech

Xie

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

310

281

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Tungsten tetraboride (WB 4 ) is an interesting candidate as a less expensive member of the growing group of superhard transition metal borides. WB 4 was successfully synthesized by arc melting from the elements. Characterization using powder X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) indicates that the as-synthesized material is phase pure. The zeropressure bulk modulus, as measured by high-pressure X-ray diffraction for WB 4 , is 339 GPa. Mechanical testing using microindentation gives a Vickers hardness of 43.3 AE 2.9 GPa under an applied load of 0.49 N. Various ratios of rhenium were added to WB 4 in an attempt to increase hardness. With the addition of 1 at.% Re, the Vickers hardness increased to approximately 50 GPa at 0.49 N. Powders of tungsten tetraboride with and without 1 at.% Re addition are thermally stable up to approximately 400°C in air as measured by thermal gravimetric analysis.dispersion hardening | indentation hardness | intrinsic hardness | nano-indentation hardness | solid solutions I n many manufacturing processes, materials must be cut, formed, or drilled, and their surfaces protected with wearresistant coatings. Diamond has traditionally been the material of choice for these shaping operations, due to its superior mechanical properties (e.g., hardness > 70 GPa) (1, 2). However, diamond is rare in nature and difficult to synthesize artificially due to the need for a combination of high temperature and high pressure. Industrial applications of diamond are thus generally limited by cost. Moreover, diamond is not a good option for high-speed cutting of ferrous alloys due to its graphitization on the material's surface and formation of brittle carbides, which leads to poor cutting performance (3). Other hard or superhard (hardness ≥ 40 GPa) substitutes for diamond include compounds of light elements such as cubic boron nitride (4) and BC 2 N (5) or transition metals combined with light elements such as WC (6), HfN (7), and TiN (8). Although the compounds of the first group (B, C, or N) possess high hardness, their synthesis requires high pressure and high temperature and is thus nontrivial (9, 10). On the other hand, most of the compounds of the second group (transition metal-light elements) are not superhard although their synthesis is more straightforward.To overcome the shortcomings of diamond and its substitutes, we have been pursuing the synthesis of dense transition metal borides, which combine high hardness with synthetic conditions that do not require high pressure (11,12). For example, arc melting and metathesis reactions have been used to synthesize the transition metal diborides OsB 2 (13, 14), RuB 2 (15), and ReB 2 (16-20). Among these, rhenium diboride (ReB 2 ) with a hardness of approximately 48 GPa under a load of 0.49 N has proven to be the hardest (16, 21). The boron atoms are needed to build the strong covalent metal-boron and boron-boron bonds that are responsible for the high hardness of these materials (12). Because of this, it is expected th...

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“…The hardness values of the sintered bodies below 0.2 mass% were close to those of other reported binderless WC. 6,18) The hardness variation of polycrystalline ceramics with grain size follows a HallPetch-like relationship.…”

Section: )mentioning

confidence: 99%

“…9) The reported Young's modulus of dense WC ceramics is still high, around 700 GPa, 1015) and the reported Vickers hardness of WC is 2428 GPa at 9.8 or 98 N testing force. 6,1618) Consequently, the presence of W 2 C in the WC sintered body may reduce its mechanical properties. The W 2 C phase in the WC sintered body from powder containing carbon is not detected by X-ray diffraction analysis.…”

Section: Introductionmentioning

confidence: 99%

“…The W 2 C phase in the WC sintered body from powder containing carbon is not detected by X-ray diffraction analysis. 6,7) Although appropriate carbon addition can produce a sintered body without W 2 C, excessive carbon addition may bring about a reduction in toughness because of residual carbon phases. Thus, the control of the carbon amount in WC powder is important for producing sound WC ceramics.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Carbon Addition on Microstructures and Mechanical Properties of Binderless Tungsten Carbide

Nino

Takahashi

Sugiyama³

et al. 2012

Mater. Trans.

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Binderless tungsten carbide (WC) with added carbon was sintered at 1800°C using a resistance-heated hot-pressing machine. Dense binderless WCs were obtained in the range from 0.25 to 0.3 mass% C, consisting of only a WC phase. The constituent phase transition with increasing carbon addition was WC + W 2 C, WC alone, and WC + residual C. Very fine WC grains were formed in the presence of W 2 C below 0.25 mass% C. When binderless WCs consisted of a WC single phase, larger WC grains were observed. While a high hardness value, more than 23.9 GPa, was measured for binderless WCs below 0.20 mass% C, the hardness decreased markedly in the range from 0.25 to 0.3 mass% C, corresponding to significant WC grain growth. A HallPetch-like relationship was confirmed between the hardness value and the grain size for dense binderless WC.

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Sparking plasma sintering of nanometric tungsten carbide

Cited by 104 publications

References 19 publications

Binderless sub-micron WC consolidated by hot pressing and treated by hot isostatic pressing

Binderless sub-micron WC consolidated by hot pressing and treated by hot isostatic pressing

Tungsten tetraboride, an inexpensive superhard material

Effects of Carbon Addition on Microstructures and Mechanical Properties of Binderless Tungsten Carbide

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