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Hydrothermal corrosion of zirconia-toughened alumina (ZTA) at 200 ºC

 
: Herrmann, M.; Seipel, B.; Schilm, J.; Nickel, K.G.; Michael, G.; Krell, A.

:

Nickel, K.G.:
Corrosion of ceramic matrix composites : Papers presented at the High Temperature Corrosion and Protection of Materials Meeting, Les Embiez, France, May 16 - 21, 2004 ; Sixth International Conference "High Temperature Corrosion and Protection of Materials" Workshop Entitled "Corrosion of Ceramic Matric Composites"
Amsterdam: Elsevier, 2005 (Journal of the European Ceramic Society 25.2005,10)
pp.1805-1812
International Symposium on High Temperature Corrosion and Protection of Materials <6, 2004, Les Embiez>
Workshop Corrosion of Ceramic Matrix Composites <2004, Les Embiez>
English
Conference Paper, Journal Article
Fraunhofer IKTS ()
Al2O3; corrosion; defect; mechanical property; ZrO2

Abstract
To investigate the corrosion behaviour of zirconia-toughened alumina (ZTA) under hydrothermal corrosion, a commercial material was compared with materials of similar composition, but fabricated using different processing methods and pure alumina. The specimens were corroded at a temperature of 200 °C in deionised water. Generally, linear corrosion kinetics were found. Pure alumina shows the lowest mass loss and the smallest rate constants. The reduction of the four-point bending strength does not correlate with the mass loss. The main parameter for the degradation is the cubic/tetragonal to monoclinic transformation of zirconia. Investigation of the corrosion of polished surfaces reveals spallation of Al2O3 grains or groups of grains surrounded by zirconia as the main mechanism. A decrease in the size of zirconia grains helps to reduce the strength degradation.

: http://publica.fraunhofer.de/documents/N-35244.html