Synthesis of monolithic SiC aerogels with high mechanical strength and low thermal conductivity

Zhimin An, Rubing Zhang*, Daining Fang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)

Abstract

The monolithic silicon carbide (SiC) aerogels were converted from catechol-formaldehyde/silicon composite (CF/SiO 2 ) aerogels through carbothermal reduction and calcination. In the process of preparing the CF/SiO 2 aerogel, a new method was proposed to produce more silicon carbide and enhanced the mechanical properties of the SiC aerogel. This method was realized by adding an alkaline silica sol as supplemental silicon source. The principle process of CF/SiO 2 aerogels converting to SiC aerogels was discussed based on experiment and results analysis, while the microstructure, mechanical properties, and thermal properties of the prepared SiC aerogels were investigated. The results show that the as-synthesized SiC aerogels consist of β-SiC and a small amount of α-SiC nanocrystalline. It possessed a mesoporous structure and a low thermal conductivity 0.049 W/(m∙K), a relatively high compressive strength 1.32 MPa, and a relatively high specific surface area 162 m 2 /g. Due to their outstanding thermal and mechanical properties, the prepared SiC aerogels present potential applications in thermal insulation field, such as space shuttles and aerospace carrier thermal protection materials.

Original languageEnglish
Pages (from-to)11368-11374
Number of pages7
JournalCeramics International
Volume45
Issue number9
DOIs
Publication statusPublished - 15 Jun 2019

Keywords

  • Aerogel
  • Mechanical strength
  • Silicon carbide
  • Thermal properties

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An, Z., Zhang, R., & Fang, D. (2019). Synthesis of monolithic SiC aerogels with high mechanical strength and low thermal conductivity. Ceramics International, 45(9), 11368-11374. https://doi.org/10.1016/j.ceramint.2019.02.216