Mechanochemical transformation of mixtures of Ca(OH){sub 2} and (NH{sub 4}){sub 2}HPO{sub 4} or P{sub 2}O{sub 5}

A detailed comparative study of the mechanochemical transformation of two mixtures: Ca(OH){sub 2}-(NH{sub 4}){sub 2}HPO{sub 4} and Ca(OH){sub 2}-P{sub 2}O{sub 5}, milled in a mortar dry grinder for different periods of time was carried out. The phase transformations obtained at each milling stage we...

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Bibliographic Details
Published in:Materials research bulletin 2006-10, Vol.41 (10)
Main Authors: Gonzalez, G., Sagarzazu, A., Villalba, R.
Format: Article
Language:English
Subjects:
ABSORPTION SPECTROSCOPY
AMMONIUM PHOSPHATES
AMORPHOUS STATE
APATITES
CALCINATION
CALCIUM HYDROXIDES
CALCIUM PHOSPHATES
CALORIMETRY
CRYSTALLIZATION
INFRARED SPECTRA
MATERIALS SCIENCE
MILLING
PHOSPHORUS OXIDES
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
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Summary:A detailed comparative study of the mechanochemical transformation of two mixtures: Ca(OH){sub 2}-(NH{sub 4}){sub 2}HPO{sub 4} and Ca(OH){sub 2}-P{sub 2}O{sub 5}, milled in a mortar dry grinder for different periods of time was carried out. The phase transformations obtained at each milling stage were studied by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, differential scanning calorimetry and thermogravimetric analysis. The transformations taking place during the first periods of milling are very different for both mixtures. However, prolonged milling, over nearly the same period, causes amorphization of both mixtures. DSC analysis of the milled powders showed the temperature of crystallization of hydroxyapatite and tricalcium phosphate ({beta}-TCP). Calcinations of all the different milled powders at 800 deg. C for 2 h, results in the formation of hydroxyapatite and {beta}-TCP.
ISSN:0025-5408
1873-4227
DOI:10.1016/j.materresbull.2006.03.004