| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Preceramic Polymers; Synthesis, Processing, Modeling, and Derived Ceramics
|
| Presentation Title |
Porous SiOC/SiC Ceramics via an Active-filler Catalyzed Polymer-derived Method |
| Author(s) |
Advaith V. Rau, Kathy Lu |
| On-Site Speaker (Planned) |
Advaith V. Rau |
| Abstract Scope |
Bulk and porous SiOC materials were synthesized via a polymer-derived ceramic (PDC) method from a polysiloxane (PSO) precursor and an iron catalyst under inert pyrolytic conditions. Fe catalyzes not only the formation and nucleation of β-SiC at lower temperatures but also promotes phase segregation of the amorphous SiOxCy phase. Samples with Fe pyrolyzed at 1100°C have an appreciable β-SiC content compared to minimal β-SiC content in the corresponding Fe-less samples. Selective etching of the SiO2 phase shows that Fe also induces segregation of the amorphous SiOxCy phase, yielding larger specific surface areas and gas sorption capability below 1300°C. At 1500°C, the pore structure changes to form interconnected networks due to the highly phase separated SiO2 and β-SiC microstructure. A Gibbs free energy minimization method was used to determine the relative phase content of the pyrolyzed samples, with the effect of Fe quantified with simplified vapor-liquid-solid and classical nucleation theories. |