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Role of Temperature and Nitrogen Flow Rate During the Carbothermic Synthesis of SiC/Si 3 N 4 Nanocomposite Powder from Gel
Author(s) -
ElSheikh Said M.,
Ahmed Yasser M. Z.,
Ewais Emad M. M.,
AlSharab Jafar F.
Publication year - 2010
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.1551-2916.2010.03670.x
Subject(s) - materials science , nanocomposite , nitrogen , volumetric flow rate , analytical chemistry (journal) , nanorod , phase (matter) , grain size , photoluminescence , chemical engineering , nanotechnology , composite material , chemistry , organic chemistry , physics , optoelectronics , quantum mechanics , engineering
This research article explores the synthesis of SiC/Si 3 N 4 nanocomposite powder via a carbothermic reaction of silica xerogel under nitrogen atmosphere. The influence of both reaction temperature and nitrogen flow rate on the properties of the produced sample was thoroughly investigated. The results revealed that both reaction temperature and nitrogen flow rate played a very important role not only on the composition ratio of SiC/Si 3 N 4 in the finally produced sample but also on the morphology of both phases. At 1300°C, spherical particles of 40 nm grain size for both phases (SiC and Si 3 N 4 ) were produced, while silicon nitride is the predominant phase. With increasing the reaction temperature, the amount of SiC increased at the expense of the amount of Si 3 N 4 till SiC becomes the predominant phase at 1500°C. At 1500°C, almost both phases have the shape of nanorods with different grain sizes. At low nitrogen flow rate and reaction temperature of 1500°C, SiC predominates while with increasing nitrogen flow rate the Si 3 N 4 becomes the predominant phase. The photoluminescence spectra revealed that a strong emission was observed at 354 and 389 nm for the sample produced at low and high N 2 flow rate, respectively. On the other hand, a high surface area of 578 and 471 m 2 /g were produced for samples prepared under low and high nitrogen flow rate, respectively. Also, the mechanism of formation of the SiC/Si 3 N 4 nanocomposite powder was postulated.