Ultrahard polycrystalline diamond from graphite

Irifune, Tetsuo; Kurio, A.; Sakamoto, Shizue; Inoue, Toru; Sumiya, Hitoshi

doi:10.1038/421599b

Cited by 714 publications

(398 citation statements)

References 13 publications

Supporting

Mentioning

374

Contrasting

Unclassified

Order By: Relevance

“…Secondly, Zarechnaya, et al [14] reported the hardness of 105 GPa to 58 GPa with 0.5 N-10 N loading forces, which is not consistent with the theoretical work [18]. The reported very hardness might duo to the nanosized nature, especially for the crystallite size of 10-15 nm is within the range of the "strongest size", such as Nano polycrystalline diamond [39] and Nano polycrystalline cubic boron nitride [40] . Furthermore, the radial crack length of Vickers indentation has been directly measured using optical microscopy.…”

mentioning

confidence: 88%

Polycrystalline γ-boron: As hard as polycrystalline cubic boron nitride

et al. 2012

Self Cite

View full text Add to dashboard Cite

The Vickers hardness of polycrystalline γ-B was measured using a diamond indentation method. The elastic properties of polycrystalline γ-B were determined using ultrasonic measurement method. Under the loading force up to 20 N, our test gave an average Vickers hardness in the asymptotic-hardness region of 30.3 GPa. We also measured the hardness and elastic properties of polycrystalline β-B and PcBN for comparison. The hardness and elastic properties for polycrystalline γ-B was found to be very close to that of PcBN.

show abstract

mentioning

confidence: 88%

Polycrystalline γ-boron: As hard as polycrystalline cubic boron nitride

et al. 2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recent experiments have shown that nanocrystalline solids, such as BN [23] or diamond [24], possess hardness "higher" than bulk diamond. These observations contradicted the reversed Hall-Petch effect that the hardness and yield stress should decrease with the grain size.…”

Section: Nanostructuresmentioning

confidence: 99%

Intrinsic hardness of crystalline solids

Tse

2010

J. Superhard Mater.

View full text Add to dashboard Cite

show abstract

“…This difference can originate either from the carbon nitride network itself (it then should be more dense in our case), or the presence of hydrogen (which tends to decrease B values as mentioned by Horvath-Bordon [16], the hydrogen presence being not excluded in our case), or the nanometric size of our material. In this last case, it is difficult to predict if a bulk morphology for c-CN x should favor or not higher values of bulk modulus as both tendancies can be encountered in literature [32][33][34][35]. Moreover, the nanocomposite morphology (the nanosized cubic phase being embedded in an amorphous nanosized matrix) makes these predictions all the more difficult.…”

Section: Goglio Et Al Revised Version Submitted To Diamond and Relamentioning

confidence: 99%

“…In particular, nanocrystalline diamond produced by high-pressure high-temperature process appears as hard as (or even harder than) single-crystal diamond [35]. As, contrary to c-CN x , the amorphous matrix embedding the crystalline nanodomains is highly unstable, further works to isolate and disperse the nanoclusters deserve careful thought.…”

Section: Goglio Et Al Revised Version Submitted To Diamond and Relamentioning

confidence: 99%

Evidence for a low-compressibility carbon nitride polymorph elaborated at ambient pressure and mild temperature

Goglio

Foy

Péchev

et al. 2009

Diamond and Related Materials

View full text Add to dashboard Cite

Superhard materials like diamond are essential for abrasive or cutting tool applications. In this way, carbon nitrides are of relevant interest because they are expected to exhibit exceptional mechanical properties, high values of bulk modulus being predicted. A smart and simple method was used to synthesize carbon nitrides and allowed elaborating a low-compressibility polymorph. The processing consists in the decomposition of commercial thiosemicarbazide (H 2 NC(S)N 2 H 3 ) powder at ambient pressure and 600°C under nitrogen flow. Besides the presence of a graphitic C 3 N 4 phase, a nanocrystalline material is obtained and is identified as a cubic carbon nitride with a cell parameter of 3.163Å. Its impressive bulk modulus of 355GPa propels it as a challenger for cubic boron nitride among lowcompressibility materials. Thus, we prove that, in accordance with previous numerous theoretical predictions, crystalline carbon nitrides exhibit exceptional compressibility behaviour. Moreover, our synthesis strategy evidences that, despite usual admitted considerations, severe and expensive pressure and temperature conditions are not mandatory to elaborate low-compressibility covalent materials, which could give new insights for their development.

show abstract

Ultrahard polycrystalline diamond from graphite

Cited by 714 publications

References 13 publications

Polycrystalline γ-boron: As hard as polycrystalline cubic boron nitride

Polycrystalline γ-boron: As hard as polycrystalline cubic boron nitride

Intrinsic hardness of crystalline solids

Evidence for a low-compressibility carbon nitride polymorph elaborated at ambient pressure and mild temperature

Contact Info

Product

Resources

About