Oxidation Behavior of Free Carbon and Si-C Bonds on Si-Ta-C-O Ceramic

抄録

Oxidation behavior of free carbon and Si-C bonds on Si-Ta-C-O ceramics prepared from organic-inorganic hybrid gels was investigated. The pyrolysis temperatures of precursor hybrid gels strongly affected the oxidation behavior of the resultant ceramics. The hybrid gel pyrolyzed at degree C was oxidized rapidly, and Si-O-Ta heterometal bonds were formed after oxidation. On the other hand, hybrid gel pyrolyzed at 1000 degree C resulted in higher resistance to oxidation because of a protective silica layer confirmed by X-ray photoelectron spectroscopy (XPS). Raman spectra showed large luminescence background, G and D bands before oxidation. However, luminescence disappeared and the both peaks were more symmetrical after oxidation. These phenomena revealed easier oxidation of radical and unstable carbon species in the ceramics.