Layered perovskites as ‘soft-ceramics’

The layered perovskite KCa 2Nb 3O 10 is shown to possess large elastic and fracture anisotropies which are explained on the basis of its structure. Its fracture toughness was measured relative to the in-basal and basal-normal directions. Combined with previously determined elastic moduli, the fractu...

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Bibliographic Details
Published in:Journal of the European Ceramic Society 1999-01, Vol.19 (13), p.2437-2447
Main Authors: Fair, Geoff, Shemkunas, Michael, Petuskey, William T., Sambasivan, Sankar
Format: Article
Language:English
Subjects:
anisotropy
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Chemical industry and chemicals
Exact sciences and technology
KCa 2Nb 3O 10
niobates
perovskites
Structural ceramics
Technical ceramics
toughness
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Summary:The layered perovskite KCa 2Nb 3O 10 is shown to possess large elastic and fracture anisotropies which are explained on the basis of its structure. Its fracture toughness was measured relative to the in-basal and basal-normal directions. Combined with previously determined elastic moduli, the fracture energy release rates and associated anisotropy were determined and discussed in terms of crack deflection characteristics. The general mechanical characteristics of KCa 2Nb 3O 10 were discussed relating to what is described as a ‘soft’ ceramic capable of sustaining considerable mechanical damage. Its high thermal stability, T m=1464°C, and its oxidation resistance are additional features that make it attractive for high temperature applications. Anecdotal demonstrations of its softness and low damage thresholds are presented, such as might be important for cerarnic–matrix composites or machinable ceramic applications.
ISSN:0955-2219
1873-619X
DOI:10.1016/S0955-2219(99)00127-2