A ceramic that goes with the flow.

A ceramic that goes with the flow

The shattering experience of dropping a china dish is a helpful reminder that ceramics are brittle. On the other hand, they are hard and resistant to chemical attack, can survive high temperatures and have a low density -- desirable properties that more malleable materials such as metals generally lack. The ideal answer would be to find a way to make ceramics more ductile at temperatures well below their melting points.

Now, a team of researchers from the University of Saarbrucken in West Germany reports the possibility of turning brittle, conventional ceramics into materials that can be deformed at low temperatures. They suggest in the Dec. 10 NATURE that the necessary ductility can be achieved by creating ceramics in which crystals are only a few nanometers in diameter. Such tiny crystals make possible the movement of atoms -- acting like a lubricant -- along the crystal interfaces when the material is deformed.

The researchers tested their idea by fabricating nanocrystalline specimens of calcium fluoride and titanium dioxide. They found that, as predicted, compressed specimens of these materials were more likely to deform than to crack.