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Bimaterial Composites via Colloidal Rolling Techniques: II, Sintering Behavior and Thermal Stresses
Author(s) -
Me Mohan,
Chen IWei
Publication year - 1999
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.1151-2916.1999.tb02260.x
Subject(s) - materials science , sintering , microstructure , composite material , waviness , shrinkage , anisotropy , thermal , layer (electronics) , physics , quantum mechanics , meteorology
Shrinkage behavior and crack formation during firing have been investigated for Al 2 O 3 /Ce‐TZP composites that have been fabricated by colloidal rolling and folding. These composites show improved sinterability and sinter isotropically after repeated rolling. Interface instability in rolling creates corrugated interfaces with large layer waviness; therefore, rolling can substantially alleviate the in‐plane sintering constraints, which leads to improved sinterability. A loss of sintering anisotropy also is observed and is directly correlated to the microstructure instability, which is coincident with the laminate‐cellular transition. Sintering cracks during heating and thermal cracks during cooling both are limited to the thick Ce‐TZP layers in the composites. The critical layer thickness and the normalized crack spacing of the thermal cracks follow the predicted behavior of elasticity theory. Thus, crack‐free, high‐density Al 2 O 3 /Ce‐TZP composites with either a laminate or cellular microstructure can be obtained, with a layer thickness of 4‐60 µm, via pressureless sintering.