Hydrothermal Corrosion of Si-Ti-C-O System (Tyrano) Fibers

Yoshinori KANNO; Eiichi YASUDA; Masahiro YOSHIMURA

doi:10.1380/jsssj.14.229

Yoshinori KANNO, Eiichi YASUDA, Masahiro YOSHIMURA

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JOURNAL FREE ACCESS

1993 Volume 14 Issue 4 Pages 229-235

DOI https://doi.org/10.1380/jsssj.14.229

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Published: June 01, 1993 Received: January 13, 1993 Available on J-STAGE: August 07, 2009 Accepted: March 22, 1993 Advance online publication: - Revised: -
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Date of correction: August 07, 2009 Reason for correction: - Correction: ABSTRACT Details: Wrong : The wet corrosion by high temperature-high pressure water has been studied on the three types of Si-Ti-C-O system (Tyrano) fibers at 300&sim;800°C under 100 MPa for 2h. The X-ray diffraction analysis and SEM observation of the scale layers and the measurement of the mass change of reaction products revealed that the pyrolysis together with forming β-SiC crystal took place in lower temperatures, while the hydro-thermal oxidation with following the formation of amorphous silica films propagated in higher temperatures. The oxidation reaction was sharply reduced as the amor-phous silica crystallizes to form cristobalite, whence the porous oxide layer is densified. The densification hindered the gaseous diffusion through the oxide film. The fiber containing 18% O (rich type), where atomic arrangement was disordered, showed a comparatively rapid pyrolytic rate. On the contrary, the fiber containing 12% O (poor type) showed a rapid oxidation rate.
Right : The wet corrosion by high temperature-high pressure water has been studied on the three types of Si-Ti-C-O system (Tyrano) fibers at 300∼800°C under 100 MPa for 2h. The X-ray diffraction analysis and SEM observation of the scale layers and the measurement of the mass change of reaction products revealed that the pyrolysis together with forming β-SiC crystal took place in lower temperatures, while the hydro-thermal oxidation with following the formation of amorphous silica films propagated in higher temperatures. The oxidation reaction was sharply reduced as the amor-phous silica crystallizes to form cristobalite, whence the porous oxide layer is densified. The densification hindered the gaseous diffusion through the oxide film. The fiber containing 18% O (rich type), where atomic arrangement was disordered, showed a comparatively rapid pyrolytic rate. On the contrary, the fiber containing 12% O (poor type) showed a rapid oxidation rate.

Abstract

The wet corrosion by high temperature-high pressure water has been studied on the three types of Si-Ti-C-O system (Tyrano) fibers at 300∼800°C under 100 MPa for 2h. The X-ray diffraction analysis and SEM observation of the scale layers and the measurement of the mass change of reaction products revealed that the pyrolysis together with forming β-SiC crystal took place in lower temperatures, while the hydro-thermal oxidation with following the formation of amorphous silica films propagated in higher temperatures. The oxidation reaction was sharply reduced as the amor-phous silica crystallizes to form cristobalite, whence the porous oxide layer is densified. The densification hindered the gaseous diffusion through the oxide film. The fiber containing 18% O (rich type), where atomic arrangement was disordered, showed a comparatively rapid pyrolytic rate. On the contrary, the fiber containing 12% O (poor type) showed a rapid oxidation rate.

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