A simple way to make tough ceramics

THE major problem with the use of ceramics as structural materials is their brittleness. One way of overcoming this problem is to introduce weak interfaces which deflect a growing crack 1 . Polymer composites of this sort can be easily prepared by surrounding fibres with liquid plastic. To make simi...

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Bibliographic Details
Published in:Nature (London) 1990-10, Vol.347 (6292), p.455-457
Main Authors: Clegg, W. J, Kendall, K, Alford, N. McN, Button, T. W, Birchall, J. D
Format: Article
Language:English
Subjects:
Acetic acid
Applied sciences
Aqueous solutions
Boron
brittleness
Building materials. Ceramics. Glasses
Ceramic industries
Ceramics
Chemical industry and chemicals
Chemistry
Composite materials
Cracks
Exact sciences and technology
Fracture toughness
Graphite
Humanities and Social Sciences
Laminating
letter
multidisciplinary
Polyvinyl alcohol
Powder
Science
Science (multidisciplinary)
Silicon
Silicon carbide
Structural ceramics
Technical ceramics
toughness
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Summary:THE major problem with the use of ceramics as structural materials is their brittleness. One way of overcoming this problem is to introduce weak interfaces which deflect a growing crack 1 . Polymer composites of this sort can be easily prepared by surrounding fibres with liquid plastic. To make similar structures with ceramic matrices and fibres is difficult and expensive, however, because traditional ceramic processing techniques of powder compaction and sintering prevent densification and cause cracking 2–4 . Here we describe a simple, inexpensive way of preparing a ceramic material that contains such weak interfaces. Silicon carbide powder is made into thin sheets which are coated with graphite to give weak interfaces and then pressed together and sintered without pressure. Relative to the monolithic material, the apparent fracture toughness for cracks propagating normal to the weak interfaces is increased more than fourfold, and the work required to break the samples increases by substantially more than a hundredfold. The technique should be readily applicable to other ceramics.
ISSN:0028-0836
1476-4687
DOI:10.1038/347455a0