Elucidation of Local Ordering and Atomic-Scale Structure in Polymer-Derived SiOC.

Area of Science:

• Materials Science
• Ceramics
• Nanotechnology

Background:

• Silicon oxycarbide (SiOC) is a versatile ceramic with tunable properties.
• Elucidating short- to medium-range order in SiOC is challenging, limiting precise composition control.
• Understanding SiOC structure is crucial for developing user-tailored applications.

Purpose of the Study:

• To elucidate changes in local chemistry and structure during SiOC pyrolysis.
• To understand the impact of pyrolysis temperature on SiOC phase formation and ordering.
• To provide atomic-scale insights into SiOC's local structure and nanoscale heterogeneities.

Main Methods:

• Utilized synchrotron scattering and spectroscopy techniques.
• Employed stochastic modeling to analyze local Si-O and Si-C environments.
• Investigated pyrolysis of a commercial SiOC polymer precursor at various temperatures (250–1100 °C).

Main Results:

• Pyrolysis at 250–800 °C yields heterogeneous SiOC with amorphous SiO₂ domains.
• At 1100 °C, a more ordered SiOC phase with SiC-like ordering forms due to redistribution.
• Residual carbon phases are detected at 1100 °C and persist at higher temperatures.

Conclusions:

• Stochastic modeling successfully decoupled Si-O and Si-C environments, revealing heterogeneous phases.
• Pyrolysis temperature significantly influences SiOC phase evolution and structural ordering.
• This work provides pathways for establishing structure-property relationships in SiOC materials.