ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Crystallization behavior of Si-C-O glasses in the temperature range of 1000°–1400°C was investigated using transmission electron microscopy (TEM) in conjunction with electron energy-loss spectroscopy (EELS). Si-C-O glasses were prepared by pyrolysis of polysiloxane networks obtained from homogeneous mixtures of triethoxysilane, TH, and methyldiethoxysilane, DH. Si-C-O glass composition depended on the molar ratio of the precursors utilized. At a ratio of TH/DH= 1, the formation of a carbon-rich glass was observed, whereas a ratio of TH/DH= 9 yielded a Si-C-O glass with excess free silicon. Both materials were amorphous at 1000°C, but showed a distinct difference in crystallization behavior on annealing at high temperature. Although TH/DH= 1 revealed a small volume fraction of SiC precipitates in addition to a very small amount of residual free carbon at 1400°C, TH/DH= 9 showed, in addition to SiC crystallites, numerous larger silicon precipitates (20–50 nm), even at 1200°C. Both materials underwent a phase separation process, SiCxO2(1-x)→xSiC + (1 - x)SiO2, when annealed at temperatures exceeding 1200°C.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.2001.tb00986.x
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