Spinal and Spinel-zirconia Composite Material Prepared at Low Temperature by Al13 as Aluminium Source

Spinel and spinel-zirconia composite powder were synthesized by soft chemistry method using [AlO4Al12(OH)(24)(H2O)(12)](7+) (abbreviated Al-13) as aluminum source. Precursor structure, reaction progress and material micro-structure evolvement were characterized by Al-27 NMR, XRD, DSC-TG and FTIR. Spinel precursor was prepared by mixing Al-13 solution and magnesium slurry which was obtained by milling the mixture of MgCl2 center dot 6H(2)O and NaOH, and its component included Mg6Al2CO3 (OH)(16) center dot 4H(2)O and beta-Al(OH)(3). Spinel is formed from calcination of this spinel precursor at 600 degrees C for 1 h, and only spinel is formed at even higher temperatures. Spinel-zirconia composite powder precursor is prepared by hydrolysis-precipitation process of Al-13 MgCl2 center dot 6H(2)O and ZrOCl2 center dot 8H(2)O solution. Spinel-zirconia composite powder can also be obtained from calcination of the precursor at 600 degrees C. FTIR spectra of the Al-13 powder and spinelzirconia precursor show that the [AlO6] absorption band shifts from 608cm(-1) to 601cm(-1) and [AlO4] from 761cm(-1) to 723cm(-1). The result shows that Al-13 has obvious advantage in synthesis of spinel and spinel-zirconia composite powders at low temperature because Al-O-Mg bond can be formed easily in precursors.