Stock material or miscellaneous articles – All metal or with adjacent metals – Composite powder
Reexamination Certificate
1998-07-27
2002-05-14
Le, Hoa T. (Department: 1773)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite powder
C423S326000, C423S335000, C423S44500R, C423S449100, C423S593100, C423S608000, C423S610000, C428S402000, C428S403000
Reexamination Certificate
active
06387531
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to powders of metal oxide with associated carbon. More particularly, the invention relates to nanoscale particles of crystalline metal oxide with associated carbon. The invention further relates to the formation of titanium oxide particles having a rutile crystalline phase.
Advances in a variety of fields have created a demand for many types of new materials. In particular, a variety of chemical powders can be used in many different processing contexts. Specifically, there is considerable interest in the application of ultrafine or nanoscale powders that are particularly advantageous for a variety of applications involving small structures or high surface area materials. This demand for ultrafine chemical powders has resulted in the development of sophisticated techniques, such as laser pyrolysis, for the production of these powders.
Ceramic powders, especially metal oxides, are of interest for a range of different applications. For example, titanium oxide powders can be used to form abrasives for the polishing of very smooth surfaces. Smooth surfaces are required in a variety of applications in electronics, tool production and many other industries. As miniaturization continues even further, even more precise polishing may be required. Current submicron technology requires polishing accuracy on a nanometer scale. Precise polishing technology can employ chemical-mechanical polishing involving a polishing composition that acts by way of a chemical interaction of the substrate with the polishing agents as well as an abrasive effective for mechanical smoothing of the surface.
SUMMARY OF THE INVENTION
In a first aspect, the invention features a collection of particles comprising:
a) metal oxide or silicon oxide, and;
b) at least about 1 percent by weight carbon, the collection of particles having an average diameter from about 5 nm to about 1000 nm.
In another aspect, the invention features a method of producing particles comprising a metal oxide and a carbon deposit, the method including pyrolyzing a molecular stream in a reaction chamber, the molecular stream including a metal precursor, an infrared absorber, an oxidizing agent and a carbon source, where the pyrolysis is driven by heat absorbed from a laser beam.
In another aspect, the invention features a collection of nanoparticles, the nanoparticles comprising rutile titanium dioxide.
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Bi Xiangxin
Kambe Nobuyuki
Kumar Sujeet
Dardi Peter S.
Kleinsmith David
Le Hoa T.
NanoGram Corporation
Patterson Thuente Skaar & Christensen P.A.
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