基于疏水作用的陶瓷浆料自发凝固成型研究进展

Progress of Spontaneous Coagulation Casting of Ceramic Slurries Based on Hydrophobic Interaction

自发凝固成型是一种新型的陶瓷浆料原位固化成型方法,通过吸附在陶瓷颗粒表面的分子链间弱作用(氢键,疏水作用)实现浆料的固化,具有普适性和适于常温大气环境操作的特点,已成为先进陶瓷制备领域的研究热点。本文简述发现兼具分散和凝固功能的阴离子型高分子分散剂的历程,以及自发凝固成型与其它原位固化成型的异同。在此基础上,基于疏水作用设计合成了系列自发凝固成型剂,进而满足以不同尺寸颗粒为原料的致密陶瓷和泡沫陶瓷的自发凝固成型。综述了面向实际应用所开发的陶瓷无界面连接、晶粒定向构造、干燥脱水等关键技术,以及致密陶瓷和泡沫陶瓷制备等研发进展,展望了未来自发凝固成型的发展方向。

Spontaneous coagulation casting(SCC)is a novel in-situ ceramic forming method,not only universal for various ceramics but also working well at room temperature in air.Here presents the finding of SCC,involving an anion dispersant which acts as both dispersing and coagulating agent.Then,the difference between SCC and other in-situ coagulation methods in principle was elucidated.In SCC,particles participate in the formation of organic network which originates from hydrophobic interaction and hydrogen bonding among the dispersant molecular chains.The ceramic gel formed by SCC is a physical gel and possesses low density which is conducive to water transportation and stress relaxation during drying.In contrast,the one by conventional gelcasting is a chemical gel in which particles are fixed by a dense organic network.Based on the hydrophobic interaction,this review focuses on the design and synthesis of a series of SCC agents to meet the demand of forming dense and porous ceramics from particles with different sizes.That is,an anion dispersant is hydrophobically modified by a surfactant with a short or long chain.The obtained two agents are used for preparation of dense and porous ceramics,respectively.Progress of key technologies in this area including ceramic joining without interface,construction of grain orientation,drying,preparation of dense ceramics and porous ceramics,by SCC is summarized.Typically,alumina disc with a diameter up to 1010 nm and alumina parts with complicated shape such as dome and guide are shown.Future development of SCC is also proposed to enable SCC tobe a more universal forming technology for advanced ceramics with a large and/or complicated dimension.