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Microstructure and Chemical Reaction in a Si 3 N 4 –TiC Composite
Author(s) -
Huang JowLay,
Chiu HungLiang,
Lee MingTung
Publication year - 1994
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.1151-2916.1994.tb05353.x
Subject(s) - titanium carbide , microstructure , materials science , silicide , hot pressing , titanium , solid solution , carbide , chemical composition , nitrogen , argon , composite number , silicon carbide , metallurgy , silicon , composite material , chemistry , organic chemistry
The effects of TiC addition to Si 3 N 4 on microstructure and the chemical aspects of Si 3 N 4 –TiC interphase reaction were investigated in samples hot‐pressed at 1800°C in Ar and N 2 . Composition of a TiC 1–x N x solid solution was predicted based on thermodynamic calculation, with titanium carbonitride taken to be an ideal solid solution. The predicted value of x = 0.7 is slightly higher than that derived from the measured lattice parameter and Vegard's law (x = 0.67). Four distinguishable areas were observed in samples hot‐pressed in nitrogen atmosphere. They were identified as β‐Si 3 N 4 , mixtures of TiC and titanium carbonitride solid solution, SiC with twins, and iron silicide. As the duration of hot‐pressing increased, more titanium carbonitride was formed, while less TiC phase remained. Thermodymanic calculations indicate one source of nitrogen gas came from the decomposition of Si 3 N 4 . The TiC particles also became more irregular, and reactants were found inside or between TiC as the hot‐pressing time was extended. Silicon carbide was not detected in samples which were hot‐pressed in argon atmosphere; however, numerous pores were found around TiC.