ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Nanocrystalline α-Al2O3 powders have been prepared by the pyrolysis of a resincompound of aluminum with polyester by a two-step calcination process. A polymeric precursor wasprepared using a complexing agent to keep the metal ions in homogeneous solution, which givessufficient flexibility for the system to exist homogeneously throughout the reaction without undergoingprecipitation. The metal-ion-polyester resin forms the precursor material on complete polymerizationreaction of aluminum nitrate, citric acid and ethylene glycol. A single-phase α-Al2O3 powder resultedafter calcinations above 1150ºC, but during heat treatment α-Al2O3 particles grow very fast bycoalescence. So 2-step calcination was used, where the first step was done in a reducing atmosphereat above 1150ºC and second calcinations were done in oxidizing atmosphere at the relatively lowtemperature of 1000ºC. The precursors and the heat-treated final powders have been characterized byX-ray diffractometry, thermogravimetry , transmission electron microscopy(TEM), and BET surfacearea analysis. The nanocrystalline α-Al2O3 particles obtained by this 2-step calcinations method had anaverage specific surface area of 〉170m2/g, with an average particle size between 40 and 60nm
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.317-318.199.pdf
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