News
Welcome to the new and developing CMR Website. Please feel free to browse the site and recommend any changes. Fresh news items may be sent to The Editor.
Tuesday 14th October 2008
The University encourages adjunct appointments as a way of enhancing teaching and research support. CMR includes a number of adjuncts within its group; these are highly regarded researchers who have associations with Curtin and CMR, often over a long period of time. Professor Brian Lawn of NIST in the USA is a long-standing adjunct appointment with CMR. Recently, the Journal of the American Ceramic Society published a list of the 11 best papers published in 110 years by the Society. One of Brian's papers (below) is included in the list and we offer him our congratulations.
G. Anstis, P. Chantikul, B. Lawn, D. B. Marshall, "A Critical-Evaluation of Indentation Techniques for Measuring Fracture-Toughness .1. Direct Crack Measurements Materials" J. Amer. Cer. Soc., 64 (9) 533-538 (1981).
Ceramics are brittle. It is tricky to measure how tough it is. Anstis, et al, showed how we can do it by following a simple procedure. Now we know how to test and develop unbreakable ceramics and ceramic steel.
Thursday 21st August 2008
X-rays from Industry to Academia - the 2008 joint AXAA and RACI Conference and Schools - will be held 10-13th October 2008.
Further details: Registration Form and Call for Abstracts
Wednesday 30th July 2008
We welcome to CMR Dr Minjigmaa Amgalan, who has come to Curtin for three months from the Mechanochemical Research Laboratory at the Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences. Minjigmaa is here as a visiting academic in the Geopolymer laboratory.
She received her PhD in 2005 in natural sciences from the University of Natural Resources and Applied Life Sciences, Vienna, Austria.
Her research interests are mechanochemistry of minerals, phosphorus fertilizer, minerals processing, solid state chemistry of natural minerals, soil chemistry, and soil inorganic carbon accumulation.
Tuesday 29th July 2008
CMR involved in another research “first’.
Another research “first” that involves CMR staff member Dr Rob Hart and CMR facilities is the subject of a paper published in the Geological Society of America’s journal, ‘Geology’, Volume 36, Issue 7 (July 2008). A media release by the CSIRO is reproduced below.
CSIRO scientist discovers natural ‘invisible’ gold
Scanning electron microscope image of the gold triangles showing their well defined crystal shape.
Nanoparticles of gold too small to be seen with the naked eye have been created in laboratories, but up until now, have never been seen in nature.
The search for these natural but ‘invisible’ nanoparticles is important. If they can be proved to exist, the knowledge will help give us a deeper understanding of how gold can be transported and deposited by geological processes, and therefore help explorers to find new gold deposits in Australia.
Now, hard evidence that gold nanoparticles have finally been seen in nature is presented in a paper published in GEOLOGY and authored by CSIRO Scientists from the Minerals Down Under National Research Flagship and CRC LEME, in collaboration with scientists from Curtin University and the University of Western Australia.
“The gold nanoparticles have not been identified earlier because they are transparent to electron beams and effectively invisible”
CSIRO’s Team Leader Mineral-Water Interactions, Exploration and Mining, Dr Rob Hough
Lead author, CSIRO’s Dr Rob Hough, explains that the particles were discovered in Western Australia. “In the southern areas of the State, groundwater is very salty and acidic. This water dissolves primary gold and re-deposits it as pure gold crystals on fracture surfaces and in open pore spaces,” he says.
“On investigation of these crystals, there appeared to be a dark band across them. However, high magnification imaging showed the band was in fact, a mass of gold nanoparticles and nanoplates. These are identical to those being manufactured in laboratories around the world for their unique properties.”
Clays from the fracture surface were then analysed. There was no gold visible, but analysis showed the clays contained up to 59 parts-per-million of gold. The research team concluded that the nanoparticles of gold they had imaged represented the ‘invisible’ gold in the clay, and that this nanosized gold was common in similar environments.
“The gold nanoparticles have not been identified earlier because they are transparent to electron beams and effectively invisible,” Dr Hough says. “However, they are probably a common form of gold in this type of natural environment worldwide, where saline water interacts with gold deposits. They also provide the first direct observation of the nanoscale mobility of gold during weathering.”
With gold fetching around (AU) $950 an ounce and expected to rise, this research is good news for Australia’s gold explorers.
Optical photograph showing the supergene gold triangles and hexagons (they appear black) on a weathered surface that is coated in iron oxides and clays
Images credits & media release by courtesy of CSIRO
A copy of the paper can be found at:
http://www.gsajournals.org/perlserv/?request=get-toc&issn=0091-7613&volume=36&issue=7
Friday 27th June 2008
Pioneering research highlight at CMR
Sodium Revealed as a Key Element in the Chemical Bonding Network of Aluminosilicate Geopolymers
Brian O’Connor (Research Leader) and Matthew Rowles (PhD Student), Curtin CMR; John Hanna, Lou Vance and Kevin Pike, ANSTO; and Mark Smith, University of Warwick
Pioneering research by the Curtin CMR on the chemical optimisation of compressive strength in aluminosilicate geopolymers, produced by sodium (Na) silicate activation of metakaolinite, revealed that a mix of Si:Al in the ratio ca. 2.5:1 optimises the compressive strength with a Na:Al ratio of 1.3 (REF 1 and FIG 1). At that time, the conventional thinking on the role of Na in geopolymer synthesis was that the Na:Al ratio should ideally be 1 to achieve charge balancing, with Na+ being present along with H2O in “cages” within the aluminosilicate bonding network.
A subsequent nano-level NMR characterisation study of the Si, Al, H and Na species has revealed that some of the Na becomes incorporated in the bonding network for high strength geopolymer blends in two ways: first as sodium aluminate sub-units and second by attaching to the silicate sub-units (FIG 2). It is now evident that sodium optimisation contributes to strength optimisation (REF 2).
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Figure 1. Contour plot of compressive strength in MPa versus Si:Al ratio and Na:Al ratio showing the samples examined in the NMR study (REF 2). |
Figure 2. Proposed model for the bonding network which shows (a) attachment of Na+ to the Al tehrahedra; (b) incorporation of Na+ in modified Si-O bridges; and (c) a broader scale view of the bonding network showing the elements in (a) and (b) above, and within the H2O filled cages (REF 2). |
References:
Matthew Rowles and Brian O’Connor (2003). J Mater. Chem., 13, 1161-1165.
M R Rowles, J V Hanna, K J Pike, M E Smith and B H O’Connor (2007). Appl. Magn. Reson., 32, 663-689.
