Rheology Control of Ceramic Slurries and Formation of Thin Layered Films by Coating

由于陶瓷烧结膜的内部结构很大程度上取决于颗粒的几何分布和颗粒间的相互吸引，因此控制陶瓷浆料的流变特性对于形成高密度的薄烧结膜是非常重要的。本研究旨在为絮凝悬浮液的流变控制提供新的机理和流变控制陶瓷浆料的制备技术。在悬浮液流变学的基础研究中，引入了缔合聚合物作为流变控制剂。缔合聚合物是亲水性长链分子，其中包含少量疏水性基团。在胶体悬浮液中，缔合聚合物通过桥接机制起絮凝剂的作用。絮凝悬浮液在非常低的剪切速率下是牛顿流。在零剪切速率极限下的液态响应表明聚合物桥在不断地形成、断裂和再形成，更多地处于静止状态。较高浓度的聚合物悬浮液即使在大应变下也具有很高的弹性。这些粒子可以通过柔软而灵活的链间结合桥连接起来。在实际应用中，通过添加表面活性剂和粘结剂聚合物制备了锆钛酸铅浆料。通过可逆桥接的弱絮凝作用，制备了厚度约为10 μm的PZT烧结膜。此外，通过使用流变控制的浆料，通过丝网印刷在塑料薄膜上形成多层荧光粉。加热时，荧光粉层被转移到CRT面板上。由于其表面光滑，填充密度高，烧结层的亮度可与传统方法制造的亮度相媲美。用可逆桥接法控制陶瓷浆料的流变学，在陶瓷微图案的形成中具有很大的潜力。少

Since the internal structure of sintered film of ceramics strongly depends on the geometrical distribution of particles and the interparticle attractions in slurry, it is important to control the rheological properties of ceramic slurries for formation of thin sintered film with high density. The study is designed to provide a new mechanism for rheology control of flocculated suspensions and preparation technique of rheology-controlled ceramic slurries. In the fundamental study of suspension rheology, associating polymers are introduced as rheology control agents. The associating polymers are hydrophilic long-chain molecules to which a small amount of hydrophobic groups is incorporated. In colloidal suspensions, the associating polymers act as flocculants by bridging mechanism. The flow of flocculated suspensions is Newtonian at very low shear rates. The liquidlike responses in the limit of zero shear rates imply that the polymer bridges are constantly forming, breaking, and re-forming … More in a quiescent state. The suspensions with polymer at relatively high concentrations are highly elastic even under large strains. The particles may be connected by bridges of interchain associations that are soft and flexible. In practical application, the PZT(lead zirconate titanate) slurries are prepared by the additions of surfactant and binder polymer. The sintered films of PZT at a thickness of about 10 μm are formed by formulating the slurries in which the particles are weakly flocculated by reversible bridging. In addition, by the use of rheologically controlled slurries, the multilayers of phosphor are formed on the plastic film by screen printing. On heating, the phosphor layers are transferred to the CRT panel. Because of smooth surface and high packing density, the sintered layer of phosphor gives the brightness comparable to that manufactured by conventional method. The rheology control of ceramic slurries by reversible bridging has great potential in formation of micropatterns of ceramics. Less