Effects of temperature and platelets on lamella wall microstructure, structural stability, and compressive strength in ice-templated ceramics

The current investigation provides insights into microstructure development as a function of sintering temperature within lamella walls of ice-templated ceramics, effects of ceramic platelets on wall microstructure, and the influence of those developments on the compressive mechanical response. The results revealed a profound influence of both on the several aspects of ice-templated ceramics, enabling an improved understanding of the structure-mechanical property relationships in these materials and limitations in the development of the ice-templated ceramic structure. In the materials without platelets, at low-temperature walls were highly porous, at intermediate temperature a pore-free lamella wall with fine-grained microstructure developed, and at high-temperature along with grain growth significant abnormal grain growth occurred as well. More dramatic was the combined effects of temperature and platelets. The effects of platelets were realized at two length scales. Some of the platelets developed lamellar bridges, whereas the platelets that became part of the lamella walls remarkably impacted wall microstructure. The current results strongly suggest that there are significant structural and mechanical strength advantages in the incorporation of large anisometric particles in ice-templated ceramics. The addition of large platelets resulted in a marked increase of compressive strength. A significant structural advantage is that the materials containing platelets exhibited improved stability to structural deformation at higher temperatures compared to the materials without the platelets. Thus, this study shows the importance of deeply probing into the structure-mechanical property relationships of ice-templated ceramics as a function of temperature and composition, providing valuable guidance into the microstructure design of these materials.