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Título del libro: Electrochemical And Performance Testing Of Nano Engineered-Coatings Based On Ana Presence When Exposed To Corrosive Environment
Título del capítulo: Porous silicon oxycarbide composites with aligned macro porosity from water-based slurry by freezecasting process

Autores UNAM:
NILOOFAR SOLTANI; AMIN BAHRAMI;
Autores externos:

Idioma:
Inglés
Año de publicación:
2016
Palabras clave:

Ceramic materials; Filled polymers; Fillers; Freezing; Polymers; Pore size; Porosity; Pyrolysis; Silica; Suspensions (fluids); Freeze Casting; Monolith; Polymer-derived ceramics; Preceramic polymer; Rice husk ash; Silicon oxycarbides; Porous silicon


Resumen:

Directionally aligned porous SiOC composites were prepared using polycarbosiloxane (SILRES® H62 C) as a preceramic polymer. To decrease shrinkage during pyrolysis, rice husk ash (RHA, amorphous silica) was added as a filler. The influence of different freezing rates and filler to polymer ratios on freeze-casting performance of 30 wt.-% aqueous polymer-silica suspensions are studied. The use of water as a liquid vehicle and dextrin as a binder was examined successfully. After pyrolysis of the green bodies at 1100 °C under nitrogen atmosphere, the monoliths show macro porous tailored lamellar structures with porosities around 65%. The results show that an increase in the polymer to RHA ratio results in smaller pore sizes and thinner pore walls. Also, by decreasing the freezing rate, pore coarsening is observed. © 2016 MS and T16®.


Entidades citadas de la UNAM: