Premium
Effect of Moisture on the High‐Temperature Stability of Unidirectionally Solidified Al 2 O 3 /YAG Eutectic Composites
Author(s) -
Bahlawane Naoufal,
Watanabe Tadahiko,
Waku Yoshiharu,
Mitani Atsuyuki,
Nakagawa Narihito
Publication year - 2000
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2000.tb01685.x
Subject(s) - eutectic system , materials science , water vapor , corrosion , yttrium , high temperature corrosion , composite material , aluminium , argon , atmosphere (unit) , moisture , composite number , oxygen , volume (thermodynamics) , metallurgy , microstructure , oxide , chemistry , physics , organic chemistry , quantum mechanics , thermodynamics
The corrosion resistance of a unidirectionally solidified alumina/yttrium aluminum garnet (Al 2 O 3 /YAG) eutectic mixture was investigated at high temperature. Samples were exposed to high temperature (1200°–1800°C) in different atmospheres, which included argon, argon/water vapor, air, and air/water vapor. The most important microstructural changes occurred at the interface between the YAG and the Al 2 O 3 . Those changes consisted of localized thermal grooving, especially when the corrosive atmosphere contained water vapor. The samples exhibited significant weight loss at high temperature (1800°C) after 20 h of exposure. The calculated volume gain that was induced by the increased surface relief was low and limited, except when the corrosive atmosphere contained air, which indicated that the presence of air (particularly oxygen) induced a more‐active corrosion process. On the other hand, no change in the flexural strength was observed, even after 100 h at 1800°C in a humid atmosphere, because of the cross‐linked structure of the composite, which limited propagation of the groove.