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Mesoporous Silicon Nitride Synthesis Via the Carbothermal Reduction and Nitridation of Carbonized Silica/RF Gel Composite
Author(s) -
Luyjew Kanoksak,
Tona Nattaporn,
Pavarajarn Varong
Publication year - 2008
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/j.1551-2916.2008.02285.x
Subject(s) - carbothermic reaction , materials science , carbonization , mesoporous material , composite number , resorcinol , chemical engineering , silicon carbide , ceramic , silicon , mesoporous silica , sol gel , pyrolysis , nitride , silicon nitride , silica gel , porosity , composite material , carbide , catalysis , nanotechnology , organic chemistry , metallurgy , scanning electron microscope , layer (electronics) , chemistry , engineering
Silicon nitride (Si 3 N 4 ), a high‐temperature structural ceramic, was synthesized in a mesoporous form by a simple approach. At first, silica/resorcinol–formaldehyde (RF) gel was formed via sol–gel polycondensation process, using resorcinol and formaldehyde as sources for porous RF structure and amino propyl trimethoxysilane as a precursor for silica. Pyrolysis of the dried gel at 250°C for 2 h following by at 750°C for 4 h resulted in silica/carbon composite that could be converted into mesoporous Si 3 N 4 or Si 3 N 4 /silicon carbide composite via the carbothermal reduction and nitridation process at 1450°C. Significant increase in surface area of the products, comparing with that of the conventional Si 3 N 4 granules, was observed. The content of silica in the starting composite was found to be a critical factor influencing both phase and porosity of the obtained product.