Functionally graded multi-material freeze-cast structures with continuous microchannels

Cathrine Deichmann Christiansen*, Kaspar Kirstein Nielsen, Rasmus Bjørk

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We present the processing of functionally graded multi-material freeze-cast structures, i.e. structures with varying material properties but continuous and homogeneous microchannels. We demonstrate this for stepwise, continuous, highly viscous and gelation freezing to achieve freeze-cast structures of graded La0.66Ca0.24Sr0.09Mn1.05O3 (LCSM9) and La0.67Ca0.27Sr0.06Mn1.05O3 (LCSM6) ceramics. The two phases are successfully distinguished from one another by the addition of 10 wt% Ce0.9Gd0.1O2 (CGO) to the LCSM6 phase. The relative Ce-content facilitates tracking of the LCSM6 phase using energy-dispersive X-ray (EDS) elemental analysis. Coupled with scanning electron microscopy, we show well-defined interfaces with continuous microchannels between the two LCSM phases in both green and sintered samples. By implementing constant freezing rates of −1.5 K/min a consistent freezing front velocity of ∼13 μm/s is maintained, and we found that a structural continuity can be maintained across the LCSM9–LCSM6/CGO interface, however, with varying pore morphology depending on the various freezing procedures.
Original languageEnglish
JournalJournal of the European Ceramic Society
Volume40
Issue number4
Pages (from-to)1398-1406
ISSN0955-2219
DOIs
Publication statusPublished - 2020

Keywords

  • Freeze-casting
  • Functionally graded materials
  • Layered structure
  • Porous ceramics
  • Magnetocaloric

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