Phase relations of a silicide/silica reaction couple at 2273 K

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Metallurgical Transactions, B

OSTI ID:260793

Pena, M ^[1]; Ramos, C; Bronson, A ^[2]

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1. Colorado School of Mines, Golden, CO (United States)
2. Univ. of Texas, El Paso, TX (United States). Dept. of Metallurgical and Materials Engineering

The phase relations of a zirconium silicide/silica reaction couple have been investigated at 2,273 K in air. After annealing times from 4 to 49 hours, the reaction couples, created by encapsulating zirconium disilicide in a quartz ampule, developed an interdiffusion zone and an inner core consisting of solidified zirconium silicide. The interdiffusion zone consisted of a silica layer, zirconia precipitates, and prior liquid silicide globules dispersed in prior liquid silica. Zirconia precipitates formed from the oxidation of the silicide melt between the protective silica layer and the two liquid regions of silicide and silica, as a result of oxygen diffusion. At 2,273 K, the inner core consisted of liquid zirconium silicide (ZrSi){sub L}, although the microstructure analysis indicated formation of proeutectic ZrSi{sub 2} and a eutectic microstructure of ZrSi{sub 2} and Si upon solidification. A constant oxygen potential developed within the interdiffusion zone and protected the silicide from oxidation even after 49 hours at temperature.

• OSTI ID: 260793
• Journal Information: Metallurgical Transactions, B, Journal Name: Metallurgical Transactions, B Journal Issue: 2 Vol. 27; ISSN MTTBCR; ISSN 0360-2141
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERAMICS
COMPATIBILITY
HEAT ENGINES
PHASE STUDIES
SILICON OXIDES
TEMPERATURE RANGE 1000-4000 K
ZIRCONIUM SILICIDES