Formation and microstructure of carbon-containing oxide scales by oxidation of single crystals of zirconium carbide

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08358.x· OSTI ID:182640

Shimada, Shiro; Nishisako, Masaru; Inagaki, Michio ^[1]; Yamamoto, Kazuhide ^[2]

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1. Hokkaido Univ., Sapporo (Japan). Dept. of Applied Chemistry
2. Dowa Mining Co., Ltd., Hachiougi, Tokyo (Japan). Central Research Lab.

The isothermal oxidation of ZrC single crystals with (100) orientation was carried out at temperatures of 500, 550, and 600 C at an oxygen pressure of 2.6 kPa for times up to 240 h. A polished cross section of the oxidized crystal was observed by backscattered electron imaging in a scanning electron microscope. Quantitative chemical analysis for Zr, O, and C and their elemental profiles by the linescan method in the ZrC and oxide scale were performed by wavelength dispersive X-ray microanalysis. A thin foil of a crystal oxidized at 600 C was examined by transmission electron microscopy. It was found that the oxide scale was divided into two regions, zones 1 and 2, which contained 14 to 23 and 7 to 10 at.% carbon, respectively. Zone 1 exhibited an almost compact, pore-free matrix of c-ZrO{sub 2}. In zone 2, some growth and aggregation of the c-ZrO{sub 2} occurred, producing 5- to 20-m-sized particles between which carbon should have been present. The thickness of zone 1 increased parabolically up to 240 h at 500 C and probably in an early period at 550 and 600 C, reaching a constant (about 2 {micro}m), in contrast to the thickness of zone 2, which increased linearly with time.

• Sponsoring Organization: USDOE
• OSTI ID: 182640
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 1 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL ANALYSIS
DIFFUSION
INTERFACES
OXIDATION
REACTION KINETICS
SCALING
SCANNING ELECTRON MICROSCOPY
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
ZIRCONIUM CARBIDES