Hollow-grained “Voronoi foam” ceramics with high strength and thermal superinsulation up to 1400 °C

Sa Li, Chang An Wang, Fuqian Yang, Linan An, Kangpyo So, Ju Li

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Nanostructures tend to be unstable at high temperatures due to large capillary energies, and therefore nanotechnology has not yet found many high-temperature applications at 1000 °C and above. By taking advantage of the high-temperature stability of refractory ceramics, here we develop a new approach of making hollow nano-grained materials to achieve thermal superinsulation across a wide temperature range, where the gaseous voids are mostly isolated within individual grain, with size comparable to the mean free path of air molecules to lower the thermal conduction by Knudsen effect. We have proved this general concept with hollow-grained La2Zr2O7 ceramic, and demonstrated exceptionally low thermal conductivity (0.016 W/(m⋅K)), the lowest ever reported for hard materials at or above room temperature. The centimeter-scale samples also have ultrahigh compressive strength (251 MPa), tensile strength in bending up to 100 MPa, and excellent thermal stability up to 1400 °C in air, due to monodispersity of pores that delays coarsening.

Original languageEnglish
Pages (from-to)35-43
Number of pages9
JournalMaterials Today
StatePublished - Jun 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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