Energetics and structure of SiC(N)(O) polymer-derived ceramics

Gerson J. Leonel, Xin Guo, Gurpreet Singh, Christel Gervais, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

This study presents new experimental data on the thermodynamic stability of SiC(O) and SCN(O) ceramics derived from the pyrolysis of polymeric precursors: SMP-10 (polycarbosilane), PSZ-20 (polysilazane), and Durazane-1800 (polysilazane) at 1200°C. There are close similarities in the structure of the polysilazanes, but they differ in crosslinking temperature. High-resolution X-ray photoelectron spectroscopy shows notable differences in the microstructure of all polymer-derived ceramics (PDCs). The enthalpies of formation (∆H°f, elem) of SiC(O) (from SMP-10), SCN(O) (from PSZ-20), and SCN(O) (from Durazane-1800) are −20 ± 4.63, −78.55 ± 2.32, and −85.09 ± 2.18 kJ/mol, respectively. The PDC derived from Durazane-1800 displays greatest thermodynamic stability. The results point to increased thermodynamic stabilization with addition of nitrogen to the microstructure of PDCs. Thermodynamic analysis suggests increased thermodynamic drive for forming SiCN(O) microstructures with an increase in the relative amount of SiNxC4−x mixed bonds and a decrease in silica. Overall, enthalpies of formation suggest superior stabilizing effect of SiNxC4−x compared to SiOxC4−x mixed bonds. The results indicate systematic stabilization of SiCN(O) structures with decrease in silicon and oxygen content. The destabilization of PDCs resulting from higher silicon content may reach a plateau at higher concentrations.

Original languageEnglish (US)
Pages (from-to)5086-5101
Number of pages16
JournalJournal of the American Ceramic Society
Volume106
Issue number8
DOIs
StatePublished - Aug 2023

Keywords

  • glass–ceramics
  • polymer precursor
  • silicon carbonitride
  • silicon oxycarbide
  • thermodynamics

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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