A morphological study of the sulfurisation of digenite to covellite using reflected polarised light microscopy

Heidi Rask Møller Frøkiær, Terence E. Warner*

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Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

A series of copper rods were reacted with sulfur vapour in evacuated glass ampoules at ∼445 °C. Product materials were characterised by powder X-ray diffraction and reflected polarised light microscopy. Copper sulfurised rapidly to digenite, γ-Cu2-xS, under these conditions, whereas the subsequent sulfurisation to covellite, CuS, was notably slower, yielding texturally distinguishable inner (secondary) and outer (primary) CuS regions. A two-stage partial sulfurisation of γ-Cu1.8S resulted in the external growth of two successive layers of primary CuS, which demonstrates decisively that covellite − besides being a p-type metal − is ionically conducting at 445 °C, although considerably less so than digenite. We infer that the growth of platy covellite crystals and their radial alignment in the primary CuS layer are a consequence of copper ion mobility being restricted to the basal plane of the covellite structure. Sulfurising a coil of copper wire at ∼445 °C is an effective method for synthesising covellite.

OriginalsprogEngelsk
TidsskriftSolid State Sciences
Vol/bind70
Sider (fra-til)74-80
ISSN1293-2558
DOI
StatusUdgivet - 2017

Fingeraftryk

Light polarization
polarized light
Optical microscopy
microscopy
Copper
copper
ampoules
X ray powder diffraction
sulfur
coils
rods
Sulfur
Vapors
alignment
wire
Wire
vapors
conduction
Glass
Crystals

Citer dette

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title = "A morphological study of the sulfurisation of digenite to covellite using reflected polarised light microscopy",
abstract = "A series of copper rods were reacted with sulfur vapour in evacuated glass ampoules at ∼445 °C. Product materials were characterised by powder X-ray diffraction and reflected polarised light microscopy. Copper sulfurised rapidly to digenite, γ-Cu2-xS, under these conditions, whereas the subsequent sulfurisation to covellite, CuS, was notably slower, yielding texturally distinguishable inner (secondary) and outer (primary) CuS regions. A two-stage partial sulfurisation of γ-Cu1.8S resulted in the external growth of two successive layers of primary CuS, which demonstrates decisively that covellite − besides being a p-type metal − is ionically conducting at 445 °C, although considerably less so than digenite. We infer that the growth of platy covellite crystals and their radial alignment in the primary CuS layer are a consequence of copper ion mobility being restricted to the basal plane of the covellite structure. Sulfurising a coil of copper wire at ∼445 °C is an effective method for synthesising covellite.",
keywords = "Chalcogenides, Diffusion, Ionic conductivity, Phase transitions",
author = "{Rask M{\o}ller Fr{\o}ki{\ae}r}, Heidi and Warner, {Terence E.}",
year = "2017",
doi = "10.1016/j.solidstatesciences.2017.06.005",
language = "English",
volume = "70",
pages = "74--80",
journal = "Solid State Sciences",
issn = "1293-2558",
publisher = "Elsevier",

}

A morphological study of the sulfurisation of digenite to covellite using reflected polarised light microscopy. / Rask Møller Frøkiær, Heidi; Warner, Terence E.

I: Solid State Sciences, Bind 70, 2017, s. 74-80.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - A morphological study of the sulfurisation of digenite to covellite using reflected polarised light microscopy

AU - Rask Møller Frøkiær, Heidi

AU - Warner, Terence E.

PY - 2017

Y1 - 2017

N2 - A series of copper rods were reacted with sulfur vapour in evacuated glass ampoules at ∼445 °C. Product materials were characterised by powder X-ray diffraction and reflected polarised light microscopy. Copper sulfurised rapidly to digenite, γ-Cu2-xS, under these conditions, whereas the subsequent sulfurisation to covellite, CuS, was notably slower, yielding texturally distinguishable inner (secondary) and outer (primary) CuS regions. A two-stage partial sulfurisation of γ-Cu1.8S resulted in the external growth of two successive layers of primary CuS, which demonstrates decisively that covellite − besides being a p-type metal − is ionically conducting at 445 °C, although considerably less so than digenite. We infer that the growth of platy covellite crystals and their radial alignment in the primary CuS layer are a consequence of copper ion mobility being restricted to the basal plane of the covellite structure. Sulfurising a coil of copper wire at ∼445 °C is an effective method for synthesising covellite.

AB - A series of copper rods were reacted with sulfur vapour in evacuated glass ampoules at ∼445 °C. Product materials were characterised by powder X-ray diffraction and reflected polarised light microscopy. Copper sulfurised rapidly to digenite, γ-Cu2-xS, under these conditions, whereas the subsequent sulfurisation to covellite, CuS, was notably slower, yielding texturally distinguishable inner (secondary) and outer (primary) CuS regions. A two-stage partial sulfurisation of γ-Cu1.8S resulted in the external growth of two successive layers of primary CuS, which demonstrates decisively that covellite − besides being a p-type metal − is ionically conducting at 445 °C, although considerably less so than digenite. We infer that the growth of platy covellite crystals and their radial alignment in the primary CuS layer are a consequence of copper ion mobility being restricted to the basal plane of the covellite structure. Sulfurising a coil of copper wire at ∼445 °C is an effective method for synthesising covellite.

KW - Chalcogenides

KW - Diffusion

KW - Ionic conductivity

KW - Phase transitions

U2 - 10.1016/j.solidstatesciences.2017.06.005

DO - 10.1016/j.solidstatesciences.2017.06.005

M3 - Journal article

VL - 70

SP - 74

EP - 80

JO - Solid State Sciences

JF - Solid State Sciences

SN - 1293-2558

ER -