Greenockite Whiskers from the Bytom Burned Coal Dump, Upper Silesia, Poland
| Autor: | Irina O. Galuskina, Evgeny V. Galuskin, Katarzyna Nowak |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
lcsh:QE351-399.2 Whiskers Greenockite chemistry.chemical_element Crystal growth 02 engineering and technology 010402 general chemistry 01 natural sciences Rod Bismuth Crystal Whisker bismuth drop whisker VQS mechanism Bytom Composite material lcsh:Mineralogy Drop (liquid) Geology 021001 nanoscience & nanotechnology Geotechnical Engineering and Engineering Geology 0104 chemical sciences coal dump chemistry VLS mechanism Poland 0210 nano-technology greenockite |
| Zdroj: | Minerals, Vol 10, Iss 470, p 470 (2020) Minerals Volume 10 Issue 5 |
| Popis: | Orange greenockite (CdS) aggregates were found in a small fumarole at a burned coal dump near Bytom, Upper Silesia, Poland and were studied using a variety of techniques in order to determine their chemistry, morphology, and most importantly, the mechanism of crystal growth. Greenockite rods, wires, and whiskers with bismuth drops on crystal tops are predominant in these aggregates. Greenockite rods oriented sub-perpendicular to the substrate surface. The rod thickness reaches 5&ndash 6 &mu m and about 10 &mu m in length. The catalyst bismuth drop has a diameter comparable to the rod thickness. Fiber forms (wires and whiskers) are sub-parallel to the substrate surface. The thickness of these forms is usually less than 2 &mu m, and the length can be close to 1 mm. The bismuth drop diameter can show a large excess over the fiber thickness. Catalyst drops on the tops of whiskers began to change their form dynamically and exploded, spraying bismuth under the electron beam effect. Rods grow along the [01&ndash 10] direction, and whiskers and wires (axial forms) along the [0001] direction. Greenockite rod crystals, carrying on top a relatively homogenous bismuth catalyst drop, were formed on the heated substrate according to the VLS (vapor&ndash liquid&ndash solid) mechanism at temperatures not lower than 270 ° C. Greenockite whiskers and wires grew just above of the substrate surface according to the VQS (vapor&ndash quasiliquid&ndash solid) mechanism at temperatures lower than 200 ° C. These mechanisms of growth have very rarely been recorded to occur in nature and even less so in burning coal dumps. The cooperative growth effects of the fiber greenockite crystals were also described. |
| Databáze: | OpenAIRE |
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