A new way of making glass
Baku, November 13 (AZERTAC). A new way to make glass has been discovered by a collaboration of researchers at the Universities of Dьsseldorf and Bristol using a method that controls how the atoms within a substance are arranged around each other. The research is published in Physical Review Letters.
When cooling a liquid below its melting temperature it either crystallizes or transforms into a glass. Glass is a peculiar state of matter: it has the mechanical properties of a solid, but an amorphous structure like a liquid.
As long ago as 1952, Sir Charles Frank at the University of Bristol argued that the structure of glasses should not be entirely disordered like a liquid but rather that it should be filled with structural motifs like the bicapped square antiprism [inset pictured].
Although such motifs have very recently been found in experiments and computer simulations on glassy materials, it has not been clear what role these play in how a liquid becomes a (glassy) solid.
The Dьsseldorf and Bristol researchers created a new type of glass in a computer through encouraging atoms in a nickel-phosphorous alloy to form the pictured polyhedron. When these polyhedra formed, the liquid no longer flowed—it had become a solid. In other words, they found that instead of cooling, a liquid can turn into a glass by changing its structure.
Paddy Royall of the University of Bristol says, "The method we developed employed computer simulations of liquids, performed on the University of Bristol`s BlueCrystal supercomputer, where the atoms were driven to form more polyhedra.
"Although many more polyhedra were formed, the atomic arrangements were still disordered rather than a periodic arrangement as seen in crystals. This means that the solid that was formed had to be a glass."
Thomas Speck of Heinrich-Heine-Universitдt, Dьsseldorf, says, "These results mean that structure can control whether a material is liquid or solid and thus open the way to design new glasses: for example metallic glasses whose great lightness and strength promise exciting applications and chalcogenide glasses which are used in memory applications and phase switch memory, a possible future technology for data storage."
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