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高纯氧化铝制备技术的进展 总被引:28,自引:0,他引:28
综述了国内外高纯氧化铝的开发动向,主要介绍拜耳法、硫酸铝铵热解法、碱式碳酸铝铵热解法、有机铝水解、热解法的工艺及其应用领域。 相似文献
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Micrometer-sized α-Al2O3 platelets with hexagonal shape were prepared by thermal decomposition of ammonium aluminum carbonate hydroxide (AACH) using AlF3 as an additive. The precursor and the calcined product were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and differential scanning calorimetry. The α-Al2O3 platelets with the size of 2-3 μm were obtained by calcining AACH at 1200 °C with 5 wt.% AlF3. The morphology modification is attributed to the various growth rates along different crystal orientations due to the adsorption and uneven distribution of AlF3. A step growth mode is responsible for the formation of the platelets. 相似文献
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AACH热解法制取高纯超细氧化铝粉 总被引:2,自引:0,他引:2
对AACH(Ammonium Dawsonite)热解法制取高纯超细氧化铝粉体进行了工业化试验研究。试验产品Al2O3纯度为三个九,平均粒径:0.5um;粒度分布:〈0.3um18.6%,〈0.5um50.6%,〈1.0um74.9%,〈1.6um92.4%,〈3.0um100%;真密度虫状结构,烧结活性高,可望应用于透明氧化铝瓷、人工宝石工业制品、IC基片、切削工具、精密光学机械零件等诸多领域。 相似文献
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Muhammad Abdullah Jamil Ahmad Mazhar Mehmood Mujtaba-ul-Hasan Hideki Maekawa 《Ceramics International》2011,37(7):2621-2624
Enhanced mechanical properties of yttria-stabilized zirconia based composites were obtained by introducing alumina whiskers as reinforcement. The alumina whiskers were formed in situ by decomposition of ammonium aluminum carbonate hydroxide (AACH) whiskers during calcination. The whiskers thus formed were amorphous and were converted to α-alumina during sintering at 1450 °C. The AACH whiskers were produced by hydrothermal treatment of an aqueous solution of urea and aluminum nitrate at 120 °C for 24 h. The Vickers hardness of the sintered composite sample increased with an increase in the alumina content up to 10 wt% and then decreased. The maximum hardness achieved at 10 wt% of alumina whiskers was 13.8 GPa, which further increased to 14.4 GPa with the addition of 1.0 wt% of cetyl-trimethyl-ammonium bromide (CTAB). The improved mechanical strength of the composites was attributed to the enhanced dispersion of alumina whiskers due to four times volume decrease during transformation of AACH to alumina and relatively lower aspect ratio of AACH whiskers as well as the deflocculating effect of CTAB. 相似文献
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煤系高岭岩制取超细氧化铝的试验研究 总被引:1,自引:0,他引:1
煤系高岭岩酸浸得到硫酸铝溶液,再采用N1923-P507混合萃取剂除铁、活性炭过滤除硅、共沉淀制取AACH结晶、热解煅烧等步骤,制得高纯超细氧化铝。讨论了用N1923-P507混合萃取剂进行三级逆流萃取时,水相pH值及萃取时间等操作条件对萃铁效果的影响;用TG-DTA研究了前驱物的热解特性,用XRD、TEM表征了AACH及其煅烧产物的物相及粒径;用ICP测定了煅烧产物的纯度。分析结果表明,铁的萃取率达到99.2%;AACH的纯度满足制取高纯超细A l2O3的要求;产品为粒径<70nm、纯度>99.95%的A l2O3。 相似文献
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纳米Al2O3粉体的制备及其热稳定性的改善 总被引:4,自引:0,他引:4
用硫酸铝铵(NH4Al(SO4)2)和碳酸氢铵(NH4HCO3)作为原材料,通过沉淀法制备了一种新型的氧化铝的前驱体——碳酸铝铵(AACH)。研究了该前驱体焙烧时的相变行为与产物形貌,发现其相变过程为:无定型(300℃)→γ(700℃)→γ θ(1050℃)→θ α(1100℃)→α(1200℃),在1200℃的高温下氧化铝粉体粒子长得很大,粒子之间的烧结很严重,产物中有很多“树枝状”硬团聚。这些都会造成粉体比表面积的损失,选择SiO2作为添加剂来改善氧化铝粉体的热稳定性,结果显示SiO2能有效地阻止氧化铝纳米粉之间的烧结,抑制氧化铝的α相变,从而改善了粉体的热稳定性能。 相似文献
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