高纯超细氧化铝粉体制备技术进展

综述了国内外高纯超细氧化铝粉体制备原理、方法及现状，介绍了近几年高纯超细氧化铝粉体制备技术的研究及开发动向。     

超细氧化铝粉体的制备工艺及其应用

系统地介绍了超细氧化铝粉体制备工艺，将各种工艺技术按干法和湿法分类，并在基本原理的基础上，主要介绍了硫酸铝铵热解、碳酸铝铵热解及无机铝盐溶胶－凝胶法等制备超细氧化铝粉体工艺的优缺点，最后介绍了超细氧化铝粉体的应用。     

高纯超细氧化铝粉体制备技术进展

综述了国内外高纯超细氧化铝粉体制备原理，方法及现状，介绍了近几年高纯超细氧化铝粉体制备技术的研究及开发动向。     

锂离子电池隔膜用超细氧化铝研制

使用性能优异的超细氧化铝制备的陶瓷隔膜,可有效提高电池的机械性能和安全性能。本文结合化学沉淀法和改良拜耳法,研究成本低廉的超细氧化铝制备工艺。首先使用硝酸铝和氨水制备超细种子,而后使用超细种子种分分解铝酸钠溶液合成前驱体,前驱体经1200℃高温焙烧获得超细氧化铝粉体。制得的氧化铝粉体纯度大于99.9%,粒径均匀,尺寸约1μm,未检出3μm以上大颗粒。     

用粉煤灰制备高纯超细氧化铝粉的研究

介绍一种利用乳化碳化体系从粉煤灰烧结料浸出液中制取超细氢氧化铝 ,进而煅烧成超细氧化铝粉的新方法。研究了浸出工艺和碳化工艺 ,分析了其化学原理 ,确定了制取高纯超细氧化铝粉的最佳实验条件和工艺参数     

我国超细氧化铝制备工艺10年进展

目前，我国超细氧化铝的制备技术和工艺已经处于世界先进行列。全面地汇总了近10年来中国超细氧化铝制备工艺的进展情况，并对各制备工艺的特点、优点及其存在的缺陷作了述评。综述研究报告和论文120余篇。     

等离子体法制备特种超细氧化铝

特种超细氧化铝近年来在各个工业领域得到了越来越广泛的应用并在国内外市场发展很快。本语言根据氧化铝水合物及铝盐等在受热情况下的相变关系，介绍了特种氧化铝的各种制备方法及传统方法中所存在的问题，提出采用先进的等离子体技术制备特种超细氧化铝粉体材料的方法及优势。     

非冶金氧化铝产品的发展动向及市场现状

简要介绍了非冶金氧化铝的分类、性能、主要质量特征、用途和应用领域;详细介绍了煅烧氧化铝、活性氧化铝、无定形铝胶、片状氧化铝和氢氧化铝、纳米氧化铝、氧化铝纤维、氧化铝膜和高纯超细氧化铝的制备方法;还介绍了国内外非冶金氧化铝的市场现状,包括非冶金氧化铝的主要生产国及其产量、进口国和出口国,分析了非冶金氧化铝迅速发展的原因,并对非冶金氧化铝的市场前景和研究动向进行了预测。     

超细氧化铝在聚乙烯醇中的分散性研究

详细研究了影响超细氧化铝在聚乙烯醇中的分散性和稳定性的因素,实验结果表明,解聚工艺、吸附工艺、pH值等对氧化铝分散液的分散稳定性有显著影响。     

高铝煤矸石制备超细氧化铝和硅酸钠联产工艺

利用盐酸酸浸法从煤矸石中浸取氧化铝,考察了固液比、反应温度、盐酸浓度、反应时间、煤矸石活化时间及活化温度等因素对氧化铝浸取率的影响,通过正交试验确定了最佳的工艺条件,使氧化铝浸取率达到84%左右;研究不同分散剂对氧化铝颗粒硬团聚的抑制作用,利用SEM、XRD对原料及制备的氧化铝进行了表征,表明制备出了高纯度、高分散性的超细氧化铝;同时还研究了氢氧化钠浓度对联产工业液体硅酸钠模数的影响。     

氧化铝多用途开发研究进展

简单介绍了氧化铝产品的种类、性质、用途。主要对氧化铝基材在介孔氧化铝材料、氧化铝陶瓷材料、多孔阳极氧化铝模板、氧化铝纤维、氧化铝膜和聚合物改性方面的应用做了阐述。介绍了氧化铝在各领域的最新研究情况。对氧化铝多用途开发应用进行了展望。     

Effect of particle size distribution of alumina on strength of glass-infiltrated alumina

Glass-infiltrated alumina composites were prepared by infiltrating glass into a pre-sintered alumina. Three different alumina preforms were obtained from various combinations of fine and coarse alumina particles. After infiltration of glass into the porous alumina preforms, their microstructure and strength were studied. The highest bending strength of 510 MPa was observed when the composite was made by mixing coarse and fine alumina powders at a ratio of 6:4. The infiltrated glass corroded the alumina preform, and the dissolved aluminum ions reprecipitated on the alumina grains during the heat-treatment for infiltration.     

Estimate of the Activation Energies for Boundary Diffusion from Rate-Controlled Sintering of Pure Alumina, and Alumina Doped with Zirconia or Titania

Sintering experiments at constant heating rates were employed to estimate the activation energy for sintering in alumina and in alumina containing 5 vol% zirconia or 5 vol% titania. Grain growth, which can complicate the analysis of sintering kinetics data, was suppressed by using uniformly and densely packed grain compacts prepared by colloidal processing. Grain-boundary diffusion is believed to have been the dominant sintering mechanism. The activation energies were 440 ± 40 kJ/mol for pure alumina, 585 ± 40 kJ/mol for alumina (titania), and 730 ± 60 kJ/mol for alumina (zirconia). The alumina and alumina (titania) results are in agreement with the values reported in the literature. The possibility that the higher activation energies for doped alumina reflect a stronger bonding at alumina interfaces in the presence of zirconium and titanium is discussed.     

Characterization of alumina modified with sulfate and phosphate

The acidity and surface properties of alumina modified with sulfate (A1-S) and phosphate (Al-P) were characterized by IR, NH₃TPD and 1-butene isomerization reaction. The Point of Zero Charge (PZC) of modified alumina and the amount of Mo anion adsorbed on modified alumina were measured. The PZC of modified alumina and the amount of Mo anion adsorbed on modified alumina decreased with increasing modifier content. Non-linear relationship between the PZC and Mo uptake in modified alumina was observed in Al-S and Al-P. The bonding mode of sulfate on alumina changed with increasing sulfate content. The Bronsted acid site appeared in alumina modified with sulfate of 10 wt%.     

氧化铝载体改性及其应用研究进展

氧化铝不仅价格低廉、易获取,且具有多孔性、大比表面积、高分散性、高热稳定性等优点,常用作催化剂载体,广泛应用于工业催化领域。氧化铝的孔结构对工业催化剂性能影响很大。为优化氧化铝载体的性能,对氧化铝的扩孔和添加助剂改性已进行了大量研究。扩孔改性可降低扩散阻力并改善传质、提高活性位点的有效利用率、增强抗结焦性能,进而提高加氢催化的产率;添加助剂改性可有效抑制氧化铝载体高温烧结和相变,防止孔结构被破坏,提高催化剂的寿命。本工作介绍了制备氧化铝的方法?拟薄水铝石脱水法和溶胶?凝胶法,综述了氧化铝的扩孔方法,总结了改性氧化铝载体的最新研究进展,包括自组装法、水热处理法、扩孔剂法;阐述了氧化铝添加助剂的改性方法,包括加入稀土金属氧化物、碱(土)金属氧化物、其它金属氧化物及非金属氧化物。最后,展望了氧化铝未来的研究和发展方向。     

The effect of nanoalumina silanisation in tetraglycidylether epoxy adhesive

The efficiency of different surface modifications on alumina nanoparticles on both filler dispersion and the final properties of the resulting adhesive nanocomposites have been investigated. A tetraglycidyldiaminodiphenylmethane (TGDDM) epoxy resin and three sample series of nanocomposites were prepared via in-situ incorporation of alumina nanoparticles into the reactor. The alumina/TGDDM nanocomposites were prepared individually using neat or non-treated alumina nanoparticles and two kinds of silane-grafted alumina nanoparticles, i.e., APS-treated alumina and GPS-treated alumina. The presence of different alumina nanoparticles in the epoxy matrices resulted in different states of nanofiller dispersion as revealed in SEM and AFM micrographs. It was elucidated that the silane treatment on alumina nanoparticles is crucial for the desired dispersion in the epoxy matrix. Besides, the appropriate filler dispersion resulted in improved thermal resistance and high degree of cure, especially for the adhesive nanocomposite containing APS-treated alumina nanoparticles. In adhesion tests, the shear strength was improved in both nanocomposites containing silane-grafted alumina with more pronounced values for the nanocomposite containing APS-treated alumina nanoparticles. The shear strength reached from 6.6 MPa for the neat epoxy adhesive to 10.2 MPa for the adhesive nanocomposite containing 5 wt % APS-treated alumina nanoparticles mainly due to high levels of dispersion of the high modulus alumina nanoparticles and effective interfacial interactions with the epoxy matrix. The adhesive peel strength of alumina/TGDDM nanocomposites showed a similar trend as in shear strength with more pronounced variations. A noticeable increase in the peel strength of the nanocomposites containing silane-grafted alumina nanoparticles appeared to correlate with greater levels of crack deflection and hence dissipation of fracture energy as observed in SEM pictures.     

Polymerization of ethylene and propylene initiated by milled alumina powder

Generation of free radicals (mechano-radicals) by the milling of alumina powder at 77 K was demonstrated by ESR. After milling of alumina in the presence of ethylene (simultaneous milling) at 77 K, polyethylene-propagating radicals instead of the alumina mechano-radicals were detected by ESR. Also the contact of ethylene with the milled alumina converted alumina mechano-radicals into polyethylene propagating radicals at a temperature above the melting point of ethylene. The products extracted by hot toluene from the simultaneous milling were identified by IR to be polyethylene, and their molecular weights were roughly 10,000. The residues after the extraction were bonded with the alumina. Polypropylene was also produced by a similar method of milling of alumina in the presence of propylene. The obtained polyproylene was atactic, and its molecular weight was about 400.     

Dehydrogenation of Ethylbenzene in the Presence of CO2 over V Catalysts Supported on Nano-sized Alumina

Carbon-covered alumina (CCA) were synthesized from mesoporous alumina and a series of carbon sources (including sucrose, furfuryl alcohol, and benzene). They had structural properties of alumina and surface characteristics of carbon. When they were used as supports for molybdenum carbide, nitride, and phosphide catalysts, significantly higher activities were obtained in hydrazine decomposition as compared to those supported on the conventional alumina. The difference in the interactions of catalytic active sites with the CCA and with the alumina supports was preliminarily deemed to be the main cause of the better performance of CCA supported catalysts. Carbon contents on alumina and carbon sources were found to be important for CCA to be a good support. Carbon deposited on alumina in a near monolayer form showed the best activities. In contrast with sucrose and furfuryl alcohol, benzene as the carbon source readily yielded CCA supports with a hydrophobic surface, which resulted in relatively low dispersions of metal and, in turn, decreased activity of the supported catalysts.     

Preparation of low-shrinkage and high-performance alumina ceramics via incorporation of pre-sintered alumina powder based on Isobam gelcasting

Mechanically robust alumina ceramics with low shrinkage were successfully prepared via gelcasting using Isobam as the gelling agent and pre-sintered alumina powder as the raw material for the first time. The influence of amount of pre-sintered alumina powder and powder's pre-sintering temperature on the viscosity of suspension and mechanical properties of low-shrinkage alumina ceramics were systematically investigated. The results showed that low-shrinkage alumina ceramics with flexural strength of 294.5?±?33.0?MPa, linear shrinkage of 7.79% and relative density of 91.5% can be obtained with the addition of 60?wt% alumina powder pre-sintered at 1600?°C. This convenient and facile approach is promising to fabricate low-shrinkage alumina ceramics with large sizes, high dimensional accuracy and complex shapes.     

Fabrication and characterization of alumina fiber by anodic oxidation and chemical dissolution processes

Alumina fiber was fabricated by an anodic oxidation process from pure aluminum or a chemical dissolution process from porous alumina. In the experiments, porous alumina layer was firstly formed on the surface of pure aluminum by anodic oxidation process in phosphoric acid electrolyte. The alumina fiber was obtained by either further anodic oxidation process or a chemical dissolution process from the porous alumina layer. The thickness of the porous alumina layer, the diameter and wall thickness of the pores in the porous alumina layer, and the length and diameter of the obtained alumina fiber were examined. The formation mechanism of the alumina fiber was discussed.