caa a22 4500 463187792 CHVBK 20180406164859.0 cr unu---uuuuu 170326e20070401xx s 000 0 eng 10.1007/s10973-006-8136-7 doi (NATIONALLICENCE)springer-10.1007/s10973-006-8136-7 TMAand SEM characterization of the thermal dehydration of australian sedimentaryopal [Elektronische Daten] [A. Smallwood, P. Thomas, A. Ray, P. Šimon] The dehydration of samples of a Coober Pedy, South Australian sedimentary white opal, displaying play of colour, was investigated using TMA by heating the samples of the specimen to a range of temperatures between room temperature and 1000 at 200°C intervals followed by cooling to room temperature. Etched fracture surfaces of the samples were then examined using SEM. The samples showed the typical expansion at low temperature up to 210°C before contraction was observed. The contraction of the opals was ascribed to both sintering, supported by morphological change observed in the SEM micrographs, and dehydroxylation of the silanol groups producing silicon-oxygen-silicon bridges resulting in a more dense silica network. Springer-Verlag, 2007 amorphous silica nationallicence dehydration nationallicence opal nationallicence SEM nationallicence TMA nationallicence Smallwood A. Department of Chemistry, Materials and Forensic Sciences, University of Technology Sydney, P. O. Box 123, NSW 20007, Sydney, Broadway, Australia aut Thomas P. Department of Chemistry, Materials and Forensic Sciences, University of Technology Sydney, P. O. Box 123, NSW 20007, Sydney, Broadway, Australia aut Ray A. Department of Chemistry, Materials and Forensic Sciences, University of Technology Sydney, P. O. Box 123, NSW 20007, Sydney, Broadway, Australia aut Šimon P. Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovak Republic aut Journal of Thermal Analysis and Calorimetry Kluwer Academic Publishers 88/1(2007-04-01), 185-188 1388-6150 88:1<185 2007 88 10973 https://doi.org/10.1007/s10973-006-8136-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10973-006-8136-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Smallwood A. Department of Chemistry, Materials and Forensic Sciences, University of Technology Sydney, P. O. Box 123, NSW 20007, Sydney, Broadway, Australia aut NATIONALLICENCE 700 1- Thomas P. Department of Chemistry, Materials and Forensic Sciences, University of Technology Sydney, P. O. Box 123, NSW 20007, Sydney, Broadway, Australia aut NATIONALLICENCE 700 1- Ray A. Department of Chemistry, Materials and Forensic Sciences, University of Technology Sydney, P. O. Box 123, NSW 20007, Sydney, Broadway, Australia aut NATIONALLICENCE 700 1- Šimon P. Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovak Republic aut NATIONALLICENCE 773 0- Journal of Thermal Analysis and Calorimetry Kluwer Academic Publishers 88/1(2007-04-01), 185-188 1388-6150 88:1<185 2007 88 10973 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer