轻质高强氧化铝微米级多孔陶瓷的制备与性能

发布时间：2018-09-18 07:55

【摘要】：近年来空气污染不断恶化,其中雾霾已成为人们的心头大患。雾霾最主要的来源之一就是机动车尾气大量排放的微米级固体颗粒。这些微米级固体颗粒则是由于机动车的大分子碳氢油料的不完全燃烧而形成。发展大分子碳氢燃油在线裂解洁净燃烧新技术是解决不完全燃烧的重要途径。本文所研究的轻质高强微米级直通孔多孔陶瓷材料是实现这一创新的关键材料。本文从研究陶瓷浆料悬浮体中产生团聚体的机理出发,根据液体介质中陶瓷粉体颗粒之间的作用势,提出了稳定固态含量的概念。运用双电层理论和DLVO等理论,揭示了分散剂和固相含量对含海藻酸钠的氧化铝基的浆料的稳定性的影响规律,以制备出适合制备微米级直通孔A1203多孔陶瓷的浆料。本文也研究了以叔丁醇为溶剂制备A1203多孔陶瓷的胶态体系固化形孔路线。并通过胶态悬浮体系的固相体积分数与陶瓷的气孔率、孔径尺寸、抗压强度和热导率的关系进行比较分析和机理研究。本文还研究了以MgO作为烧结助剂提高材料的抗压强度的规律,并实现了氧化铝多孔陶瓷的胶态聚合固化形孔本研究改进了定向冷冻升华形孔法,采用环境友好的海藻酸钠作为粘结剂创建了一条绿色环保的制备微米级直通孔氧化铝多孔陶瓷的工艺路线。由于明显改善了生坯的强度而提高了工艺的可靠性,降低了制备成本。成功制备了具有均匀分布且相互平行的轻质高强氧化铝微米级直通孔多孔陶瓷材料。所获得的微米级直通孔多孔陶瓷的开口孔隙率范围从百分之五十到百分之八十,抗压强度从3.4MPa到32.3MPa,渗透率达到4×10-11m2以上。导出冰冻干燥形孔分散剂TAC-开口气孔率数学模型。本文还研究了海藻酸钠离子交换凝胶形孔法,通过对形孔和干燥工艺的控制,制备出了外部形状规整,内部微米级直通孔高度有序定向排列的轻质高强多孔氧化铝陶瓷。样品无明显裂纹和空洞,其相互平行的直通孔孔径在80～250ttm之间。以此方法制备的多孔陶瓷样品的渗透率比相同气孔率的氧化铝泡沫陶瓷提高了一个数量级。抗压强度也远远大于已知的相同气孔率的非定向孔多孔陶瓷。这种多孔陶瓷材料,只需15%固相含量,压强度就可达到44.2±5.4MPa。
[Abstract]:Air pollution has been worsening in recent years, in which haze has become a major problem. One of the most important sources of haze is the micron-sized solid particles emitted from vehicle exhaust. These micron solid particles are formed by incomplete combustion of the vehicle's macromolecular hydrocarbon oil. It is an important way to solve incomplete combustion of macromolecular hydrocarbon oil by on-line pyrolysis and clean combustion. In this paper, the light and high strength micron porous ceramic materials are the key materials to realize this innovation. In this paper, based on the study of the mechanism of agglomeration in ceramic slurry suspension, the concept of stable solid content is put forward according to the interaction potential between ceramic powder particles in liquid medium. The influence of dispersant and solid content on the stability of alumina based slurry containing sodium alginate was revealed by using the double layer theory and DLVO theory. The slurry suitable for the preparation of micron straight through porous A1203 ceramics was prepared. In this paper, the solidified pore formation route of A1203 porous ceramics prepared by tert-butanol as solvent was also studied. The relationship between the volume fraction of solid phase and the porosity, pore size, compressive strength and thermal conductivity of the colloidal suspension system was compared and analyzed. In this paper, the rule of improving the compressive strength of alumina porous ceramics by using MgO as sintering assistant was studied, and the method of directional freezing sublimation pore forming was improved by realizing the solidification of porous alumina ceramics by colloidal polymerization. The environmentally friendly sodium alginate was used as binder to create a green and environmentally friendly porous alumina ceramic with micron size. The reliability of the process is improved and the preparation cost is reduced because of the obvious improvement of the strength of the raw billet. Light and high strength alumina micron size straight through porous ceramic materials with uniform distribution and parallel to each other were successfully prepared. The open porosity range from 50% to 80%, compressive strength from 3.4MPa to 32.3 MPa, permeability above 4 脳 10-11m2. A mathematical model of TAC- open porosity for freeze-drying dispersant was derived. In this paper, the sodium alginate ion exchange gel method was also studied. By controlling the pore shape and drying process, the light weight and high strength porous alumina ceramics were prepared. There are no obvious cracks and voids in the sample, and the pore diameter of the parallel through pore is between the 80~250ttm. The permeability of porous ceramic samples prepared by this method is one order of magnitude higher than that of alumina foam ceramics with the same porosity. The compressive strength is also much higher than that of non-directional porous ceramics with the same porosity. The compressive strength of the porous ceramic material can reach 44.2 卤5.4 MPA with only 15% solid content.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ174.1

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