Nanoindentation study of macerals in coals from the Ukrainian Donets Basin
<p>This article discusses the mechanical properties of macerals in Carboniferous coals from the Ukrainian Donets Basin, covering a maturity range from 0.62 to 1.47 %Rr (vitrinite reflectance). The inherent inhomogeneity of geological samples requires characterization at the micr...
| Published in: | Advances in Geosciences |
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| Main Authors: | , , , , , |
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-08-01
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| Online Access: | https://www.adv-geosci.net/45/73/2018/adgeo-45-73-2018.pdf |
| Summary: | <p>This article discusses the mechanical properties
of macerals in Carboniferous coals from the Ukrainian Donets Basin, covering
a maturity range from 0.62 to 1.47 %Rr (vitrinite reflectance). The
inherent inhomogeneity of geological samples requires characterization at the
micro-/nanoscale, and hence material parameters, such as hardness <i>H</i> and
reduced elastic modulus <i>E</i><sub>r</sub>, were obtained from twelve coal specimens via
nanoindentation tests. Different material properties and maturity trends were
acquired for the individual maceral groups (vitrinite, inertinite,
liptinite). The results indicate that apart from maturity, multiple factors
like microstructural features and depositional environment control the
mechanical properties of macerals in coals. <i>H</i> and <i>E</i><sub>r</sub> of vitrinites
show a complex relationship with maturity due to additional influence of
microstructural features such as nanoporosity or mineral inclusions and
complex changes in the organic matter structure with increasing rank. The
mechanical behaviour of inertinites is mainly controlled by the prevailing
conditions (temperature, exposure) during paleo-wildfires. <i>E</i><sub>r</sub> and <i>H</i> of
liptinites are strongly influenced by transformational processes related to
devolatilization at low to medium rank, as well as later hydrocarbon
generation. Variations in the depositional environment (e.g. increased
organic S content due to marine influence) might play an additional role.</p> |
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| ISSN: | 1680-7340 1680-7359 |