Pressure-induced amorphization of wollastonite (CaSiO3) at room temperature

Serghiou, George; Hammack, William S.

doi:10.1063/1.464361

Cited by 36 publications

(14 citation statements)

References 27 publications

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“…These hydrous minerals have thus similar pressure ranges of amorphization. Serghiou & Hammack (1993) observed near 26 GPa amorphization of wollastonite, CaSiO 3 , a pyroxenoid mineral which displays extensive polytypism. Without elaborating further, they suggested from X-ray diffraction experiments that amorphous CaSiO 3 can be considered as a defective long-period modulated wollastonite phase.…”

Section: Miscellaneous Mineralsmentioning

confidence: 95%

Pressure-induced amorphization of minerals: a review

Richet

Gillet

1997

ejm

166

126

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A variety of minerals transform to an amorphous material when statically compressed to a few tens of GPa. With quartz and the quartz-type forms of GeO 2 and A1PO 4 as examples, pressure-induced amorphization is first described with reference to differential stresses, crystalline transformations, compression mechanisms and shearing processes. Less comprehensive information is available for the amorphization of other minerals, but similar features are nevertheless observed for framework silicates, pyroxenes, olivines and hydrous silicates. The differences and similarities between amorphous substances obtained by cooling of liquids, static compression or decompression of crystals, moderate heating of high-pressure minerals at 1 atm, and shock waves are then reviewed. Finally, the thermodynamics of amorphization is discussed and the mechanistic interpretations of amorphization are presented, with special reference to elastic and dynamic instabilities and shearing processes.

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Section: Miscellaneous Mineralsmentioning

confidence: 95%

Pressure-induced amorphization of minerals: a review

Richet

Gillet

1997

ejm

166

126

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“…1a) except for diffraction lines of platinum and thus can be explained by pressure-induced * E-mail:yusa.hitoshi@nims.go.jp amorphization, as has been reported for silica (Hemley et al 1988) and silicates (Serghiou and Hammack 1993;Hemmati et al 1995). The diffraction pattern was an amorphous halo ( Fig.…”

Section: Resultsmentioning

confidence: 52%

Unquenchable hexagonal perovskite in high-pressure polymorphs of strontium silicates

Yusa

Akaogi

Sata

et al. 2005

American Mineralogist

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The presence of hexagonal silicate perovskite (6H-BaTiO 3 type) was confi rmed in the SrSiO 3 compound by in-situ angle dispersive X-ray diffraction at high pressure. The perovskite was crystallized from pressure-induced amorphous SrSiO 3 in a diamond anvil cell by laser heating at 35 GPa. On releasing the pressure, the perovskite also changed into an amorphous state as does CaSiO 3 perovskite. This SrSiO 3 perovskite, with a tolerance factor greater than unity, forms a face-sharing SiO 6 octahedron, which leads to a structure with hexagonal symmetry. Incorporation of Sr into CaSiO 3 perovskite in the early stage of the differentiation in the Earth s mantle might have infl uenced the symmetry of CaSiO 3 perovskite in the present lower mantle. As far as we know, this is the fi rst report suggesting the existence of hexagonal perovskite in silicates.

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“…At the same time, a close inspection of the Raman spectra for the second group of samples (see Fig. 4 ) detects an appearance of Ca–O local vibrational mode at about 336 and 412 cm −1 , and Raman features at 642 and 971 cm −1 corresponded the stretching vibration of the monomer SiO 4 and the stretching vibration of the chain SiO 4 tetrahedron, respectively [ 19 ]. These modes, as it is known [ 19 ], characterize the wollastonite form of CaSiO 3 .…”

Section: Resultsmentioning

confidence: 99%

Silicon Substrate Strained and Structured via Cavitation Effect for Photovoltaic and Biomedical Application

et al. 2016

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A hybrid structure, which integrates the nanostructured silicon with a bio-active silicate, is fabricated using the method of MHz sonication in the cryogenic environment. Optical, atomic force, and scanning electron microscopy techniques as well as energy dispersive X-ray spectroscopy were used for the investigation of the morphology and chemical compound of the structured surface. Micro-Raman as well as X-ray diffraction, ellipsometry, and photovoltage spectroscopy was used for the obtained structures characterization. Ellipsometer measurements demonstrated the formation of the layer with the thicknesses ~700 nm and optical parameters closed to SiO2 compound with an additional top layer of the thicknesses ~15 nm and the refractive index ~1. Micro-Raman investigation detects an appearance of Ca–O local vibrational mode, and the stretching vibration of SiO4 chains characterized the wollastonite form of CaSiO3. A significant rise in the value and an expansion of the spectral range of the surface photovoltage for silicon structured via the megasonic processing was found. The concept of biocompatible photovoltaic cell on the base of Si\CaSiO3 structure for the application in bioelectronics was proposed.

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Pressure-induced amorphization of wollastonite (CaSiO3) at room temperature

Cited by 36 publications

References 27 publications

Pressure-induced amorphization of minerals: a review

Pressure-induced amorphization of minerals: a review

Unquenchable hexagonal perovskite in high-pressure polymorphs of strontium silicates

Silicon Substrate Strained and Structured via Cavitation Effect for Photovoltaic and Biomedical Application

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