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Constrained sintering of alumina stripe patterns on rigid substrates: Effect of stripe geometry

: Jamin, C.; Rasp, T.; Kraft, T.; Guillon, O.

Preprint urn:nbn:de:0011-n-2641372 (2.8 MByte PDF)
MD5 Fingerprint: 39af66338b7f4481a4d146eac7b16dc6
Created on: 5.12.2014

Journal of the European Ceramic Society 33 (2013), No.15-16, pp.3221-3230
ISSN: 0955-2219
Deutsche Forschungsgemeinschaft DFG
U 993/2-2
Journal Article, Electronic Publication
Fraunhofer IWM ()
thick film; simulation; constrained sintering; alumina

The sintering behaviour of alumina stripes deposited on sapphire substrates by micromolding in capillaries - a soft lithographic method - with lateral dimensions from 10 to 500 µm and thicknesses between 7 mm and 32 µm was studied. Unlike in continuous films, the lateral sintering strain is not negligible, thus reducing the constraint imposed by the substrate. Lateral shrinkage depends on the stripe width and thickness. The degree of constraint exerted on alumina stripes by a rigid sapphire substrate was investigated by comparing the lateral and vertical strains and is found to be dependent on stripe geometry. The formation of a delaminated, highly dense edge zone was observed at the free boundaries. Its influence on overall densification and local density distribution depends on its extension compared to the total film width. A gradient in local density was found that varied both with stripe thickness and width as predicted by finite element and discrete element simulations.