Microstructural observation of the ZrC/ZrO{sub 2} interface formed by oxidation of ZrC

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.1996.0326· OSTI ID:389284

Shimada, S; Inagaki, M ^[1]; Suzuki, M ^[2]

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1. Department of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060 (Japan)
2. JEOL, Akishima 196 (Japan)

The oxidation of ZrC single crystals having (100) faces was performed at a temperature of 600{degree}C at an oxygen pressure of 2.6 kPa. A polished cross section of oxide scale was observed by backscattered electron imaging (BEI) in a scanning electron microscope (SEM). The oxide scale was observed to consist of two subscales, zones 1 and 2; zone 1 is adjacent to the ZrC. The thickness of zone 1 was kept constant (about 2 {mu}m), independent of oxidation time. The interfacial microstructure between ZrC and cubic ZrO{sub 2} ({ital c}-ZrO{sub 2}) phase in zone 1 was observed by high resolution transmission electron microscopy, by using an extremely thin foil of an oxidized crystal. The {ital c}-ZrO{sub 2} crystallites of 2 to 10 nm in size showing the (111), (200), and (220) lattice fringes were aggregated and distributed in an area about 10 to 20 nm away from the interface, with an amorphous layer observed adjacent to the ZrC. Electron dispersive X-ray analysis (EDX) indicated that carbon is concentrated at the interface; a decreasing oxygen concentration gradient in the oxide phase and away from the interface in the ZrC suggests the formation of oxygen deficient ZrO{sub 2{minus}{ital x}} and oxycarbide on the respective sides of the interface. A black coating layer appeared, resulting from detachment or dissolution of zone 2, when a crystal oxidized for 1 h was treated in a HF solution. The layer was shown by the Raman spectrum to be amorphous carbon. {copyright} {ital 1996 Materials Research Society.}

• OSTI ID: 389284
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 10 Vol. 11; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
CHEMICAL COMPOSITION
INTERFACES
OXIDATION
RAMAN SPECTRA
TEMPERATURE RANGE 400-1000 K
TIME DEPENDENCE
ZIRCONIUM CARBIDES
ZIRCONIUM OXIDES