WANG Jie, JIANG Xiaoqing, QIAN Xianwei, LI Xuebin, WAN Linguo, ZOU Jie, JIAN Jiawen
(Advanced Intelligent Sensing Technology Laboratory, School of Information Science and Engineering, Ningbo University, Ningbo 315211, Zhejiang, China)

Abstract: In the process of preparing thick film ceramic devices through high temperature co-fired ceramics (HTCC) technology, the addition of casting additives (binders and plasticizers) plays a critical role in determining the performance of the final ceramics. The effects of additive content on key properties of yttria-stabilized zirconia (YSZ), including slurry viscosity, film thickness, shrinkage rate, relative density, electrical conductivity and mechanical strength of the sintered ceramics, were systematically studied. It is revealed that an increase in additive content leads to an increase in slurry viscosity and a decrease in film thickness. During sintering, both shrinkage rate and thermal weight loss of the ceramic increase with increasing additive content. In particular, density of the sintered ceramics decreases as the mass fraction of additives increases. Compared with the low-additive content samples, the sintered ceramics exhibit a significantly lower flexural strength and electrical conductivity. Meanwhile, there is an increase in the activation energy of oxygen ion migration. Moreover, relative density of the YSZ ceramics reaches a maximum value of 98.95% when the mass fraction of casting additives is 12%. At this optimally formulated state, the ceramics exhibit the highest conductivity, while the activation energy reaches the lowest recorded level of 0.9456 eV. Our study provides valuable insights into the role of casting additives in defining the properties of YSZ ceramics, which may help manufactures develop effective formulation and processing strategies to optimize the performance of thick film ceramic devices.
Key words: additive; tape casting; YSZ ceramics; relative density; conductivity; activation energy