Such dimensions are far smaller than those of the crystalline grains in conventional metals or ceramics. These new substances are called ''nanophase materials'' because the individual grains making up their microscopic structure are no larger than a few nanometers, a few billionths of a meter. Siegel believes, may be in preparing superconducting ceramics as solid froths of ultrafine particles compacted under pressure.
The discovery caused a sensation among physicists, who recognized that high-temperature superconductors might be used to levitate and pull railroad trains magnetically, store electricity in huge coils without loss, power clinical imaging magnets at greatly reduced cost and even transmit power far more efficiently than is now possible.īut one of the obstacles that has impeded exploitation of these materials in practical devices is their brittleness and the fact that boundaries between the grains that make up their structure tend to block the superconductance of current. Three years ago scientists discovered the first such high-temperature superconductors - ceramic compounds in which copper oxide is the main component. Conventional superconductors work only at about the temperature of liquid helium, which is much more expensive, colder and harder than liquid nitrogen to store and handle.
One of the key potential applications of such ceramics is in making wires capable of conducting large electric currents without resistance at temperatures as high as that of liquid nitrogen, a cooling medium that is relatively inexpensive and easy to handle. Siegel of Argonne National Laboratory said that his laboratory had not only created metals with greatly increased hardness but had prepared non-brittle ceramics that change shape rather than break under pressure. The same atoms redistributed from the interior of large grains to the boundaries between small grains can produce sharp differences in the behavior of materials, scientists said.įor example, participants were shown samples of pure, unalloyed copper and silver, normally soft metals, that had been made nearly as hard as iron by altering the frothiness of their microscopic structures. The grains that make up a piece of metal can be made visible by etching the surface of the metal. The size of the grains in a metal solidified from its melted form depends largely on the speed at which the metal is cooled rapid cooling generally results in small grains. Each grain contains a lattice of atoms or molecules arranged in a regular, periodic order, but the lattices in neighboring grains are not aligned with each other, and therefore sharp boundaries are created between the grains. Most solid matter, except for glassy materials, is made up of crystalline grains joined together at their boundaries in mosaic patterns. The 4,000 physicists attending last week's meeting of the American Physical Society here heard a dozen reports by scientists from major research institutions concluding that frothiness, or its equivalent in solid materials, graininess, affects the properties of matter in previously unsuspected ways.
#ATOMIC SOCIETY HUMBLE HOW TO#
The humble soap bubble is guiding scientists in the creation of a new family of materials that are expected to touch off a revolution in technology.īy controlling the fine structure of grainy materials similar to soap-bubble froths, physicists have learned how to make soft metals hard and hard ceramics soft they have developed new electronic substances that are potentially important for computers, and have taken some long steps toward harnessing the phenomenon of high-temperature superconductivity.
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