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Conventional and Microwave‐Induced Sintering Mechanisms for Reaction‐Bonded Aluminum Oxide with Zirconium Oxide Additions
Author(s) -
Kato Masahiro,
Goto Yasuhiro
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.tb01149.x
Subject(s) - sintering , materials science , microwave , oxide , zirconium , metallurgy , phase (matter) , aluminium , zirconium oxide , chemical engineering , chemistry , physics , organic chemistry , quantum mechanics , engineering
Powder compacts consisting of Al, Al 2 O 3 , and ZrO 2 were heated by microwave radiation. Tracing the phase evolution during reaction bonding revealed the reaction mechanism. In the case of conventional heating, the compacts expanded slightly at temperatures of <700°C due to Al surface oxidation and expanded sharply at temperatures greater than 700°C as oxidation proceeded from the surface to the interior. Then, the compacts shrank at 1550°C due to sintering. For the case of microwave heating, the compacts expanded at temperatures of <550°C due to the formation of Al 3 Zr. This Al 3 Zr formation was caused by the preferential heating of ZrO 2 relative to Al and Al 2 O 3 by microwave radiation. Then, Al 3 Zr was oxidized to form Al 2 O 3 and ZrO 2 at temperatures of >1000°C. Finally, the compacts shrank at 1550°C due to sintering, similarly to conventional sintering.