Brookhaven Scientists Awarded Patent for New Method of Making Metal Oxides
UPTON, NY --
Scientists at the U.S. Department of Energy's Brookhaven National
Laboratory were recently issued U.S. Patent No. 6,179,897 for a
novel way of making metal oxides. This class of compounds, which
includes magnesium oxide (a key ingredient of numerous products,
including the stomach-settling formula Milk of Magnesia) and zinc oxide
(famous for its place on lifeguards' noses), is commonly used in
catalysts and cosmetics, and is important to the growing field of
The new method
for making metal oxides, patented by Brookhaven Senior Chemist John
Larese and retired Brookhaven Chemist Walter Kunnmann, avoids some of
the problems of traditional methods, "and allows greater control of
the particle size and chemical composition of the product," says
difference: The traditional method requires processing a molten metal at
high temperature; the newly patented method entirely avoids the dangers
and difficulties of working with the liquid phase.
directly transforming the solid metal to its liquid state, "we
combine the metal with graphite in a vessel and heat it to form an
intermediate compound, a metal carbide," says Larese. Then the
scientists apply more heat to decompose the metal carbide. The metal
gets released as a vapor, which can then be oxidized to form a pure
metal oxide powder.
heat can be added in a controlled fashion, the scientists can vary the
vapor density. The more dense the vapor, the larger the particles they
produce. The result is the ability to produce metal oxide powders with
uniform particle sizes anywhere from 5 to 500 nanometers.
also allows the scientists to add other elements such as chromium, iron,
copper, and nickel to make more complex particles. These additives, or
"dopants," can alter the electrical, optical, and magnetic
properties of the final product, so they can be tailored for a variety
example, adding chromium as a dopant to magnesium oxide has
learning how to deposit metal clusters and molecules of various sizes on
the surface of tiny powder particles may have applications in many other
areas of materials science where scientists are trying to manipulate the
physical properties of materials by creating or controlling nanoscale
even imagine all the potential uses of this technique," Larese
says. "Our goal right now is to explore the range of materials we
can produce by this method. The excitement is going to be discovering
the things that other people havenšt thought of."
This work was
funded by the U.S. Department of Energy.
Department of Energy's Brookhaven National Laboratory conducts research
in the physical, biomedical, and environmental sciences, as well as in
energy technologies. Brookhaven also builds and operates major
facilities available to university, industrial, and government
scientists. The Laboratory is managed by Brookhaven Science
Associates, a corporation founded by Stony Brook University and Battelle,
a nonprofit applied science and technology organization.