【作者】 崔学民；

【导师】 欧阳世翕； 黄勇；

【作者基本信息】 中国建筑材料科学研究院 ， 材料学， 2003， 博士

【摘要】 叠层制造成型(Laminated Object Manufacturing)已经在结构陶瓷和功能陶瓷器件的制备中被广泛应用，尤其是在电容器、电感、高温燃料电池、陶瓷基板等领域更是备受关注。因此，实现叠层制造成型的关键技术—流延工艺的研究显得尤其重要。本研究在传统水基流延成型工艺的基础上，借鉴乳胶漆的制备技术，选用乳胶作粘结剂，克服了传统水基流延工艺的诸多不足，成功制备出性能良好，并在室温下可直接叠层的流延素片，为更好应用于叠层制造成型奠定了基础。 本文首次系统研究了乳胶体系水基流延浆料的制备、流变学特性、浆料干燥及成膜机理的相互关系，通过优化浆料制备、流延以及干燥控制等参数，制备出表面光滑平整、结构均匀、强度和柔韧性较高、容易叠层和烧结的流延素片；而且无毒无污染，有很好的经济效益和社会效益，达到国际先进水平。 本文通过深入研究陶瓷颗粒特性、浆料PH值、粘结剂、分散剂、增塑剂以及消泡剂的比例等因素对水基流延浆料流变学性能的影响，制备了稳定性良好，流动性适宜，适合流延成型的高固相体积分数的陶瓷浆料；结合流延工艺参数优化，得到了水基流延浆料的最佳配比范围。 本文对乳胶体系水基浆料的干燥和成膜机理进行研究后发现，乳胶和浆料成膜机理是一个溶剂不断蒸发造成玻璃化温度不断升高，粘度不断增大的一个干燥过程，其中增塑剂和成膜助剂起决定性作用。浆料干燥过程分为受蒸发控制的恒速干燥过程和受扩散控制的降速干燥过程两个阶段，二者之间存在一个临界点；恒速干燥阶段对温度的敏感性高于扩散控制阶段。 利用该流延工艺制备的流延片，厚度在60～1000μm之间可控，素坯相对密度可以达到54％左右。烧结活性较好粉体所制备的流延片在烧结温度1580℃、保温2小时的条件下获得了相对密度为96.5％、无翘曲变形的薄片烧结体。 利用乳胶粘结剂的压敏胶粘特性，对陶瓷材料的叠层制造工艺进行研究改进，首次实现了室温、低压力下用流延片直接叠层成型陶瓷器件。坯体的微观结构和烧结致密性与叠层压力有很大关系，叠层压力为16MPa时得到的素坯密度最大，结构最均匀，烧结后相对密度可达到97％，层间界面消失且不开裂。乳胶流延片的粘结强度与乳胶特性、用量、增塑剂比例等因素直接相关。本研究结果对陶瓷材料的叠层制造成型具有一定的指导意义。更多还原

【Abstract】 Lamination of ceramics is an important process in the manufacturing of layered structures, such as multiplayer capacitors, inductance, heat exchangers, solid oxide fuel cells (SOFC), etc. Tape casting is the wide and crucial technique for fabrication of green sheets for laminated object manufacturing (LOM). On the base of latex dope technology, the study overcomes some defects of traditional aqueous tape casting by selecting latex binder, and gets a smooth-surface and high-strength green tape to lamination of ceramics at room temperature.This paper focuses systematically on the relationship with the preparation of slurry, the forming film mechanism of latex binder and the rheological behaviors of the suspensions. The aqueous tape casting process can produce green tapes with smooth surface, homogenous structure, high toughness and strength, easy lamination and sintering by improving technique parameters of tape casting process. The technology without toxin and pollution has already arrived at an advanced level with great economic benefits and social benefits on the world.The influences of the characteristics of ceramic powders, PH value of slurries, latex binder, dispersants and plasticizers on water-based tape casting process were studied systematically. Aqueous ceramic slurry with good stability, suitable fluidity, and high powder loading was prepared successfully. The best range of slurry composition was determined by experiments.The drying process of the alumina suspensions is shown to follow a two-stage mechanism (the first stage: evaporation controlled process; and the second stage: diffusion controlled process). The latex binder fraction, plasticizers ratio and casting thickness are not influence of the first stage, but influence of the resistance of diffusion on the second stage. The drying temperature is mostly influence of the first stage. During the drying stage of suspensions, the compressive force compressed the latex particles distortion, which results in cross-linking structures in contacted latex particles of the solidified tapes. Glycerol and TBP improve the film quality by decreasing the Tg of latex binder systems.Ceramic green tapes, with thickness vary from 60-1000jnm and with the relative density about 54%, were fabricated by aqueous tape casting process with latex binder. The relative density of sintered tapes arrived at 96.5% on the sintering condition of 1580℃ for 2h, which were fabricated by ALCOA alumina powders. The sintered sample has not warped and deformed.A new method that allows the green tapes lamination at room temperature without any adhesive to laminate ceramics is described in this paper. Because the Tg of styrene-acrylic latex binder is very low, then the latex binders possess some pressure sensitive adhesion characteristic at room temperature, which the green tapes can adhere to a part at room temperature and low pressure. The laminated green parts densities and deformation significantly depended on the lamination pressure. The green body of laminated pressure of 16 MPa has homogenous microstructure and good sintering behavior, and the relative density can reach 97%. The interfacial of sintered laminated sample was disappeared. The bonding strength between green tapes was influenced by the characteristic of latex, fraction of binder and plasticizers ratio et al.更多还原