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Phase Formation and Microstructure of Titanium Oxides and Composites Produced by Thermal Plasma Oxidation of Titanium Carbide
Author(s) -
Ishigaki Takamasa,
Li YaLi,
Kataoka Eiji
Publication year - 2003
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.1151-2916.2003.tb03496.x
Subject(s) - rutile , microstructure , materials science , anatase , titanium , phase (matter) , titanium carbide , carbide , chemical engineering , transmission electron microscopy , evaporation , composite material , metallurgy , chemistry , nanotechnology , photocatalysis , biochemistry , physics , organic chemistry , engineering , thermodynamics , catalysis
The phase formation and microstructure of titanium oxides and composites produced by Ar–O 2 thermal plasma oxidation of titanium carbide powders were investigated in detail by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Relationships between the phase compositions and microstructures of the oxides were established by combined structural and phase analyses, in correlation with synthesis conditions and phase formation mechanisms. It is revealed that vapor condensation favored the formation of anatase, which existed as smaller particles, while liquid/solid oxidation favored the formation of rutile, which appeared as larger particles or composites. A higher oxygen input in the plasma gases (Ar + O 2 ) enhanced the formation of anatase due to impeded oxidation and evaporation. A small amount of Ti 4 O 7 and Ti 3 O 5 was detected in the larger particles coexisting with rutile or TiC. These suboxides were formed as intermediates in solid oxidation of TiC or precipitated from the Ti–C–O melt during cooling. Furthermore, extensive cracks, dislocations and stresses were observed in the monolithic rutile and composites, in association with the rapid quenching in this high‐temperature in‐flight oxidation process.