On the catalytic growth of synthetic diamonds

Badzian, Andrzej; Klokocki, Andrzej

doi:10.1016/0022-0248(81)90387-0

Cited by 22 publications

(3 citation statements)

References 5 publications

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“…XRD measurements are also defined by 2θ Bragg angles between 10°and 160°with a step size of 0.02°. In addition to diamond material, two other phases have been identified on diffractograms: tungsten carbide (WC), cobalt carbide (CoC x ) [12] and traces of cobalt (ε-Co).…”

Section: Phase Analysis and Quality Factormentioning

confidence: 99%

A study on PDC drill bits quality

Yahiaoui

Gerbaud

Paris

et al. 2013

Wear

108

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The quality of innovating PDC bits materials needs to be determined with accuracy by measuring cutting efficiency and wear rate, both related to the overall mechanical properties. Therefore, a lathe-type test device was used to abrade specific samples. Post-experiment analyzes are based on models establishing coupled relations between cutting and friction stresses related to the drag bits excavation mechanism. These models are implemented in order to evaluate cutting efficiency and to estimate wear of the diamond insert. From here, an original approach is developed to encompass cutting efficiency and wear contribution to the overall sample quality toward abrasion. Four main properties of PDC material were used to define quality factor: cobalt content in samples that characterizes hardness/fracture toughness compromise, other undesired phase as tungsten carbide weakening diamond structure, diamond grains sizes and residual stresses distribution affecting abrasion resistance.

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Section: Phase Analysis and Quality Factormentioning

confidence: 99%

A study on PDC drill bits quality

Yahiaoui

Gerbaud

Paris

et al. 2013

Wear

108

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“…Figure 4(b) shows that the graphene layers have grown epitaxially on the catalyst, which has a spacing of 0.35 nm, subject to (100) of primitive cubic CoC x carbide. 29 To confirm the role of Ga in the carbon capsule formation, two more in situ experiments were performed and the results are shown in Fig. 5, with the left and right panels acquired from the TEM grid with Ga Fig.…”

Section: Resultsmentioning

confidence: 98%

Formation of carbon capsules from an amorphous carbon film by Ga and Ni/Co catalysts in a transmission electron microscope

et al. 2009

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Direct conversion of an amorphous carbon (C) film to capsules by gallium (Ga), and nickel and cobalt (NiCo) alloy particles upon heating is investigated in situ by transmission electron microscopy (TEM). Capsules are catalyzed in an NH3 atmosphere when the temperature is raised to 1050 °C. High resolution TEM reveals that graphene flakes initially nucleate at the surface of the catalysts, then segregate and transform into faceted multi-shell capsules upon continued heating. The solubility of carbon in the NiCo alloy particles can be differentiated from the solubility of carbon in Ga particles by the thickness of the walls. The C/Ga binary phase in nanoparticles is discussed regarding the formation of thin-walled carbon capsules.

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“…They discovered that a molten metal could be used to lower the temperatures and pressures needed to synthesise diamond making it feasible given the technology of the time but did not understand the mechanism of growth. The role of the molten metal was strongly contested until a study in 1981 concluded that it must play a role as both a solvent for graphitic carbon and a catalyst for the re-precipitation of diamondiferous carbon [7], lowering the activation energy barrier of its formation.…”

Section: Introductionmentioning

confidence: 99%

The influence of microstructure on the mechanical properties of polycrystalline diamond: a literature review

Scott

2017

Advances in Applied Ceramics

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Polycrystalline diamond (PCD) is an extremely high-performance cutting tool material used in the machining of rock, high-strength, non-ferrous metal alloys and carbon-fibre-reinforced composites. It is favoured for its exceptional hardness and wear resistance which results in at least an order of magnitude improvement in performance over previous technologies in almost all metrics. However, PCD suffers from unpredictable brittle fracture and degradation at high temperature during service which limits its capabilities in cutting applications. The literature on the link between its microstructure and its mechanical properties, including strength, toughness and flaw size distribution as measured by pseudo-static tests, is investigated. The conclusions of the seminal paper on this topic are re-examined in the light of modern ceramics research and an alternative explanation is put forth for the strengthgrain size relationship published in this paper. All known literature values for strength and toughness vs. grain size and binder content are collated showing no overall trend in strength with binder content but moderate trends in all other combinations. The common claim of weak grain boundaries is brought into question in the light of the lack of any evidence of this fracture mode being evident in pseudo-static tests. The industrial literature on wear testing and failure modes of PCD in service and service-like tests is examined to bridge the gap between pseudo-static and dynamic, application-based experiments. Six main failure modes are recorded and summarised with intergranular fracture being the most conspicuously absent from the pseudo-static tests. It is suggested that the temperature generated by friction in dynamic tests causes the weakening of grain boundaries, resulting in a transition from transgranular to intergranular fracture and a call for further research in this area is made.

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On the catalytic growth of synthetic diamonds

Cited by 22 publications

References 5 publications

A study on PDC drill bits quality

A study on PDC drill bits quality

Formation of carbon capsules from an amorphous carbon film by Ga and Ni/Co catalysts in a transmission electron microscope

The influence of microstructure on the mechanical properties of polycrystalline diamond: a literature review

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