Oxidation of single crystals of hafnium carbide in a temperature range of 600 to 900 C

Journal Article · Tue Jul 01 04:00:00 EDT 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb03048.x· OSTI ID:529539

Shimada, Shiro; Nakajima, Kenichiro; Inagaki, Michio ^[1]

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1. Hokkaido Univ., Sapporo (Japan). Dept. of Applied Chemistry

The isothermal oxidation of HfC single crystals with (100) orientation was carried out using an electromicrobalance at temperatures of 600 to 900 C at an oxygen pressure of 2 to 8 kPa. Nonisothermal oxidation was performed by a simultaneous thermogravimetry-differential thermal analysis-mass spectrometry analysis. A polished cross section of the oxidized crystal was observed by backscattered electron imaging in a scanning electron microscope. Quantitative chemical analysis for Hf, O, and C and their elemental profiles in the HfC and oxide scale was carried out by wavelength dispersive X-ray microanalysis. It was found that the oxide scale consists of two regions, zones 1 and 2, both of which showed the existence of carbon. The carbon content at the middle point of zone 1 was about twice that in zone 2, which contained 7 to 14 at.% carbon. Zone 1 showed an almost compact and pore-free phase: its thickness remained constant (1 to 2 {micro}m) after a prolonged time. The thickness of zone 2 increased linearly with time. The oxidation mechanism including interfacial reaction responsible for the deposition of carbon is discussed.

• Sponsoring Organization: Ministry of Education, Science and Culture (Japan)
• OSTI ID: 529539
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 7 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON
HAFNIUM CARBIDES
INTERFACES
MONOCRYSTALS
OXIDATION
OXYGEN
REACTION KINETICS
SCALING
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K