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Room‐Temperature Freeze Casting for Ceramics with Nonaqueous Sublimable Vehicles in the Naphthalene–Camphor Eutectic System
Author(s) -
Araki Kiyoshi,
Halloran John W.
Publication year - 2004
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.1151-2916.2004.tb06353.x
Subject(s) - eutectic system , camphor , materials science , microstructure , lamellar structure , ceramic , casting , particle (ecology) , chemical engineering , metallurgy , chemistry , organic chemistry , oceanography , engineering , geology
Freeze casting for Al 2 O 3 was accomplished at room temperature with nonaqueous sublimable vehicles in the naphthalene–camphor eutectic system with a eutectic temperature of 31°C. A fully dense sintered body (>99.5% of theoretical density (T.D.)) was obtained with a eutectic composition vehicle, whereas at most 90% T.D. was obtained with an off‐eutectic (i.e., hypo‐ or hypereutectic) composition vehicle due to formation of large uniquely shaped voids. Microstructural observation suggested that growing pro‐eutectic crystals rejected the suspended Al 2 O 3 particles to form large voids during the solidification process. At the eutectic composition, formation of fine lamellar microstructure in a solidified vehicle is considered to inhibit particle rejection resulting in large voids.