Discontinuous dissolution of spinel precipitates in the Al{sub 2}O{sub 3}-Fe{sub 2}O{sub 3} system

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:94071

Lee, H Y ^[1]; Kang, S J.L. ^[2]

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1. Sunmoon Univ., Chungnam (Korea, Republic of). Dept. of Materials Science and Engineering
2. Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of). Dept. of Ceramic Science and Engineering

The discontinuous dissolution of oxide particles has been investigated in the Al{sub 2}O{sub 3}-Fe{sub 2}O{sub 3} system by changing oxygen partial pressure (P{sub O{sub 2}}) and temperature. In P{sub O{sub 2}} change experiment, 95Al{sub 2}O{sub 3}-5Fe{sub 2}O{sub 3} (in wt %) powder compacts were sintered at 1,500 C in P{sub O{sub 2}} = 0.001 atm and then annealed at 1,500 C in air. In temperature change experiment, 85Al{sub 2}O{sub 3}-15Fe{sub 2}O{sub 3} (in wt%) powder compacts were sintered at 1,600 C in air and then annealed at 1,450 C in air. During annealing the sintered specimens, which contained corundum grains and iron aluminate spinel particles, the grain boundaries migrated concomitantly with the dissolution of spinel particles. A discontinuous dissolution of spinel precipitates thus occurred, when the grain boundary migration of alumina in a two phase mixture of corundum and spinel was induced by P{sub O{sub 2}} or temperature change. The present result would be a distinct observation of the discontinuous dissolution of precipitates in ceramic systems.

• OSTI ID: 94071
• Report Number(s): CONF-941144--; ISBN 1-55899-258-8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
ANNEALING
COMPOSITE MATERIALS
CORUNDUM
DISSOLUTION
GRAIN BOUNDARIES
IRON OXIDES
MICROSTRUCTURE
OXYGEN
PARTICLES
PHASE DIAGRAMS
SCANNING ELECTRON MICROSCOPY
SINTERING
SPINELS
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION