Al13低温合成尖晶石和尖晶石氧化锆复合材料

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²⁷Al NMR、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AlOMg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.

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 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.