A novel large-volume Kawai-type apparatus and its application to the synthesis of sintered bodies of nano-polycrystalline diamond

Irifune, Tetsuo; Isobe, Futoshi; Shinmei, Toru

doi:10.1016/j.pepi.2013.09.007

Cited by 43 publications

(28 citation statements)

References 27 publications

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“…For the synthesis of larger and crack-free samples of garnets with the compositions shown in Fig. 6, we used a multianvil apparatus operated in a 6,000 ton press (BOTCHAN-6000)13 at the Geodynamics Research Center. The design of the cell assembly adopted for these runs was virtually the same as shown in Supplementary Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Relatively large NPD rod samples up to ∼1 cm in both diameter and length can now be produced using a large-volume multianvil apparatus13, and have been successfully applied for various industrial tools as the first commercialized products obtained in the ultrahigh pressure regime (generally defined as the pressure range of above 10 GPa in materials synthesis). By applying a similar technique, we recently reported synthesis of nano-polycrystalline stishovite14 (a high-pressure polymorph of SiO 2 quartz) from silica glass with both high hardness and toughness at a pressure of 15 GPa and temperatures above 1,000 °C.…”

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confidence: 99%

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Pressure-induced nano-crystallization of silicate garnets from glass

Irifune¹,

Kawakami²,

Arimoto³

et al. 2016

Nat Commun

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Transparent ceramics are important for scientific and industrial applications because of the superior optical and mechanical properties. It has been suggested that optical transparency and mechanical strength are substantially enhanced if transparent ceramics with nano-crystals are available. However, synthesis of the highly transparent nano-crystalline ceramics has been difficult using conventional sintering techniques at relatively low pressures. Here we show direct conversion from bulk glass starting material in mutianvil high-pressure apparatus leads to pore-free nano-polycrystalline silicate garnet at pressures above ∼10 GPa in a limited temperature range around 1,400 °C. The synthesized nano-polycrystalline garnet is optically as transparent as the single crystal for almost the entire visible light range and harder than the single crystal by ∼30%. The ultrahigh-pressure conversion technique should provide novel functional ceramics having various crystal structures, including those of high-pressure phases, as well as ideal specimens for some mineral physics applications.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Pressure-induced nano-crystallization of silicate garnets from glass

Irifune¹,

Kawakami²,

Arimoto³

et al. 2016

Nat Commun

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Section: Experimental Methodsmentioning

confidence: 99%

“…Some recovered samples synthesized at 12 GPa and 1600°C with rutile structure were crushed and ground into powders using a pestle and a mortar made of nanopolycrystalline diamond. 24,25 First, we tried to crush them using an alumina mortar, but we observed a huge amount of contamination of alumina because SiO 2 stishovite is much harder than alumina. [11][12][13][14] Then we synthesized nanopolycrystalline diamond materials using a 6000tonf-Kawai-type apparatus (BOTCHAN-6000 25 in Geodynamics Research Center, Ehime University) and made the nanopolycrystalline diamond mortar, which enables us to grind stishovite crystals without contamination.…”

Section: Experimental Methodsmentioning

confidence: 99%

A Complete Solid Solution with Rutile‐Type Structure in SiO₂–GeO₂ System at 12 GPa and 1600°C

et al. 2015

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High pressure and temperature synthesis of compositions made of (Si1−x,Gex)O2 where x is equal to 0, 0.1, 0.2, 0.5, 0.7, and 1 was performed at 7–12 GPa and 1200–1600°C using a Kawai‐type high‐pressure apparatus. At 12 GPa and 1600°C, all the run products were composed of a single phase with a rutile structure. The lattice constants increase linearly with the germanium content (x), which indicates that the rutile‐type phases in the SiO2–GeO2 system form a complete series of solid solutions at these pressure and temperature conditions. Our experimental results show that thermodynamic equilibrium state was achieved in this system at 12 GPa and 1600°C, but not at 1200°C. At lower pressures (7 and 9 GPa) and 1600°C, we observed the decomposition of (Si0.5,Ge0.5)O2 into SiO2‐rich coesite and GeO2‐rich rutile phases. The silicon content in the rutile structure increases sharply with pressure in the vicinity of the coesite–stishovite phase transition pressure in SiO2.

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“…Their extraordinary properties like extreme hardness, thermal stability, fracture toughness, and wear resistance have led to their commercial production for usage in manufacturing of hard tools, etc. 14,15 . Study of materials at high pressure, also helps to quell our basic curiosity about structure of the earth or distant planets and stars in the universe, as can be seen by some recent interesting studies.…”

Section: Introductionmentioning

confidence: 99%

High Pressure:One of the many Tools to Study Material Properties at Extreme Conditions

Garg¹

2017

Current Science

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High pressure is a powerful and clean variable, which when applied can bring about large changes in structure and properties of materials. It can be used to simulate the conditions found deep inside the earth or in different planetary interiors. It is widely used in chemical industry, especially when the chemical reaction products have lower volumes than the initial reactants, and also in the food preservation industry, where it ensures that aromas and flavours are not lost even after preservation. Materials under pressure can be studied both theoretically and experimentally. In this article apart from discussing how to set up a basic high pressure experiment using the DAC, some examples have been elaborated to show how both experiments and theory complement each other and both put together can help in a deeper understanding of the changes brought about by application of high pressure.

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A novel large-volume Kawai-type apparatus and its application to the synthesis of sintered bodies of nano-polycrystalline diamond

Cited by 43 publications

References 27 publications

Pressure-induced nano-crystallization of silicate garnets from glass

Pressure-induced nano-crystallization of silicate garnets from glass

A Complete Solid Solution with Rutile‐Type Structure in SiO₂–GeO₂ System at 12 GPa and 1600°C

High Pressure:One of the many Tools to Study Material Properties at Extreme Conditions

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A novel large-volume Kawai-type apparatus and its application to the synthesis of sintered bodies of nano-polycrystalline diamond

Cited by 43 publications

References 27 publications

Pressure-induced nano-crystallization of silicate garnets from glass

Pressure-induced nano-crystallization of silicate garnets from glass

A Complete Solid Solution with Rutile‐Type Structure in SiO2–GeO2 System at 12 GPa and 1600°C

High Pressure:One of the many Tools to Study Material Properties at Extreme Conditions

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Product

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A Complete Solid Solution with Rutile‐Type Structure in SiO₂–GeO₂ System at 12 GPa and 1600°C