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Highly Porous SiOC Bulk Ceramics with Water Vapor Assisted Pyrolysis
Author(s) -
Li Jiake,
Lu Kathy
Publication year - 2015
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13634
Subject(s) - pyrolysis , materials science , ceramic , hydrofluoric acid , chemical engineering , silicon carbide , microstructure , porosity , mesoporous material , phase (matter) , specific surface area , etching (microfabrication) , carbon fibers , silicon , composite material , catalysis , organic chemistry , metallurgy , chemistry , composite number , engineering , layer (electronics)
Micro/mesoporous SiOC bulk ceramics with the highest surface area and the narrowest pore size distribution were prepared by water‐assisted pyrolysis of polysiloxane in argon atmosphere at controlled temperatures (1100°C–1400°C) followed by etching in hydrofluoric acid (HF) solution. Their pyrolysis behaviors, phase compositions, and microstructures were investigated by DSC, FTIR, XRD, and BET. The Si–O–Si bonds, SiO 2 ‐rich clusters, and SiO 2 nanocrystals in the pyrolyzed products act as pore‐forming species and could be etched away by HF. Water injection time and pyrolysis temperature have important effects on phase compositions and microstructures of the porous SiOC bulk ceramics, which have a maximum‐specific surface area of 2391.60 m 2 /g and an average pore size of 2.87 nm. The porous SiOC ceramics consist of free carbon phase, silicon carbide, and silicon oxycarbide.