Al_(13)低温合成尖晶石和尖晶石-氧化锆复合材料

Spinal and Spinel-zirconia Composite Material Prepared at Low Temperature by Al_(13) as Aluminium Source

以[AlO4Al12(OH)24(H2O)12]7+(简写为Al13)溶液为铝源,采取湿化学的方法合成尖晶石及尖晶石-氧化锆复合粉体.采用27AlNMR、DSC-TG、XRD和FTIR等研究前驱体结构、反应过程及微结构演变.将氯化镁、氢氧化钠混合研磨后加入Al13溶液中,得到由Mg6Al2CO3(OH)16.4H2O和β-Al(OH)3组成的前驱体,经过600℃煅烧形成尖晶石,更高温煅烧产物仍为尖晶石单相.以Al13、MgCl2.6H2O和ZrOCl2.8H2O为原料制备的前驱体经600℃煅烧,同样获得尖晶石和四方相氧化锆.Al13粉末和尖晶石-氧化锆复合粉体的FTIR谱显示,归属于[AlO6]的吸收谱带由608cm-1移至601cm-1,归属于[AlO4]的吸收谱带由761cm-1移至723cm-1.前驱体中形成的Al-O-Mg键合是以Al13为铝源合成尖晶石和尖晶石-氧化锆复合粉体具有低温合成的主要原因.

Spinel and spinel-zirconia composite powder were synthesized by soft chemistry method using [AlO4Al12（OH） 24（H2O） 12]7＋（abbreviated Al13） as aluminum source. Precursor structure, reaction progress and material microstructure evolvement were characterized by 27Al NMR, XRD, DSC-TG and FTIR. Spinel precursor was prepared by mixing Al13 solution and magnesium slurry which was obtained by milling the mixture of MgCl2·6H2O and NaOH, and its component included Mg6Al2CO3（OH）16·4H2O and β-Al（OH）3. Spinel is formed from calcination of this spinel precursor at 600℃ for 1h, and only spinel is formed at even higher temperatures. Spinel-zirconia composite powder precursor is prepared by hydrolysis-precipitation process of Al13, MgCl2·6H2O and ZrOCl2·8H2O solution. Spinel-zirconia composite powder can also be obtained from calcination of the precursor at 600℃. FTIR spectra of the Al13 powder and spinelzirconia 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 Al13 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.