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Oxidation of HIPed TiC Ceramics in Dry O2, Wet O2, and H2O Atmospheres.
- Source :
- Journal of the American Ceramic Society; Apr2006, Vol. 89 Issue 4, p1218-1225, 8p, 3 Black and White Photographs, 1 Chart, 7 Graphs
- Publication Year :
- 2006
-
Abstract
- Isothermal oxidation of dense TiC ceramics, fabricated by hot-isostatic pressing at 1630°C and 195 MPa, was performed in Ar/O<subscript>2</subscript> (dry oxidation), Ar/O<subscript>2</subscript>/H<subscript>2</subscript>O (wet oxidation), and Ar/H<subscript>2</subscript>O (H<subscript>2</subscript>O oxidation) at 900°–1200°C. The weight change measurements of the TiC specimen showed that the dry, wet, and H<subscript>2</subscript>O oxidation at 850°–1000°C is represented by a one-dimensional parabolic rate equation, while the oxidation in the three atmospheres at 1100° and 1200°C proceeds linearly. Cross-sectional observation showed that the dry oxidation produces a lamellar TiO<subscript>2</subscript> scale consisting of many thin layers, about 5 μm thick, containing many pores and large cracks, while H<subscript>2</subscript>O-containing oxidation decreases pores in number and diminishes cracks in scales. Gas evolution of CO<subscript>2</subscript> and H<subscript>2</subscript> with weight change measurement was simultaneously followed by heating the TiC to 1400°C in the three atmospheres. Cracking in the TiO<subscript>2</subscript> scale accompanied CO<subscript>2</subscript> evolution, and the H<subscript>2</subscript>O-containing oxidation produced a small amount of H<subscript>2</subscript>. A piece of single crystal TiC was oxidized in <superscript>16</superscript>O<subscript>2</subscript>/H<subscript>2</subscript><superscript>18</superscript>O to reveal the contribution of O from H<subscript>2</subscript>O to the oxidation of TiC by secondary ion mass spectrometry. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00027820
- Volume :
- 89
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Journal of the American Ceramic Society
- Publication Type :
- Academic Journal
- Accession number :
- 20238371
- Full Text :
- https://doi.org/10.1111/j.1551-2916.2005.00876.x