Gel casting based on thermal solidification andits interfacisl chemistry for production of defect-free ceramics

本研究将作者发现的陶瓷料浆凝固新现象应用于陶瓷生坯的生产中。目前研究人员也开发了强大的表征工具，用于检查车身的结构，以制造无瑕疵的绿色车身。这些新方法对于开发基于热固化的凝胶注模成型新方法和开发高性能无缺陷陶瓷是必不可少的。本研究表明，该方法可以成型无大缺陷的氧化铝坯体。生坯具有高度均匀的显微组织。坯体具有很高的烧结性，在低于正常烧结温度10℃时，致密化达到理论值的98%。通过改善均匀度可以进一步降低烧结温度，其固化机理涉及作为分散剂的聚丙烯酸与氧化铝表面界面化学的热变化。由于表观吸附热的增加，吸附增加是导致固化的原因。

This research applies the new solidification phenomenon of ceramic slurry, which was found by the present investigator, for the production of ceramic green body. Powerful characterization tools, which were also developed by the present investigators, were applied to examine the structure of the body to made green bodies without flaw. These new approaches are indispensable for developing novel forming method called gel casting based on thermal solidification and also for developing high performance ceramics without flaw.This study shows that alumina green body without large flaws can be formed by the present method. The green body was found to have highly uniform microstructure. The body has high sinterability and was densifled to 98% of theoretical value at a temperature 1OOK below the normal sintering temperature. The sintering temperature may be further reduced by improved homogeneity The solidification mechanism involves the thermal change of interface chemistry between the poly-acrylic acid used as a dispersant and the alumina surface. The increased adsorption due to an apparent endo-thermal heat of adsorption is responsible for the solidification.