The Powder Preparation of Blue Cobalt Aluminate at 210 oC Using the Malonate Method 


Vol. 31,  No. 1, pp. 47-51, Jan.  2010
10.5012/bkcs.2010.31.1.047


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  Abstract

A powder, containing 80 percent of blue cobalt aluminate (CoA24) crystallites, was synthesized at 210 oC using a (metal nitrate-malonic acid-ammonium hydroxide-ammonium nitrate) system. The optimal amount of concentrated ammonia water and initial decomposition temperature were determined for the blue CoA24 crystallites preparation. Three CoA24 precursor pastes, corresponding to the various amounts of concentrated ammonia water, were prepared by evaporating the initial solutions in an electric furnace fixed at 80 oC under a vacuum of 25 torr. The initial solution was used to dissolve the starting materials. The powder with the maximum content (80%) of blue CoA24 crystallites was prepared when the prepared precursor was decomposed at 210 oC. The blue CoA24 crystallite content in the prepared sample decreased with increasing initial decomposition temperature. For 0.2 mole of the Al3+ ion, the chemical compositions of the precursor corresponded to molar ratios of 0.4, 1.40, 2.56 and 2.00 for the Co2+ ion, malonic acid, ammonia and ammonium nitrate per mole of the Al3+ ion, respectively. The blue CoA24 crystallite content in the sample decreased with the amount of ammonia deviated from the optimal value. The characteristics of the powders were examined using X-ray diffraction, optical microscopy, Fourier transformation infrared spectroscopy and the Brunauer- Emmett-Teller technique.

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  Cite this article

[IEEE Style]

G. Y. Lee, D. H. Lee, H. G. Kim, Y. Y. Kim, "The Powder Preparation of Blue Cobalt Aluminate at 210 oC Using the Malonate Method," Bulletin of the Korean Chemical Society, vol. 31, no. 1, pp. 47-51, 2010. DOI: 10.5012/bkcs.2010.31.1.047.

[ACM Style]

Gong Yeol Lee, Dong Hoon Lee, Hong Gun Kim, and Yoo Young Kim. 2010. The Powder Preparation of Blue Cobalt Aluminate at 210 oC Using the Malonate Method. Bulletin of the Korean Chemical Society, 31, 1, (2010), 47-51. DOI: 10.5012/bkcs.2010.31.1.047.

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ISSN(Print) 0253-2964
ISSN(Online) 1229-5949