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Published September 2021 | public
Journal Article

Freeze-cast honeycomb structures via gravity-enhanced convection

Abstract

The effect of gravity on directional solidification was investigated in solution-based freeze casting. A preceramic siloxane-based polymer was freeze-cast with a cyclohexene solvent from two different directions: that against the direction of the gravitational force and that in concert with the gravitational force. Because the density of preceramic polymer is higher than the solvent, the segregated polymer creates a denser solution ahead of the freezing front than the underlying solution when the freezing direction is the same as the gravity direction. This results in convective flow in the liquid phase. This convective flow influences constitutional supercooling, which changes not only the pore size of freeze-cast structure but also the pore morphology from dendritic to cellular pores.

Additional Information

© 2021 The American Ceramic Society. Issue Online: 06 July 2021; Version of Record online: 19 May 2021; Accepted manuscript online: 23 April 2021; Manuscript accepted: 19 April 2021; Manuscript revised: 13 April 2021; Manuscript received: 07 March 2021. This work was supported by the National Science Foundation under CBET-1911972, and the Rothenberg Innovation Initiative (RI2) program at Caltech. The authors would like to thank Peter W. Voorhees for valuable advice and useful discussions of this work.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023