Babcock & Wilcox Technical Services Y-12, Llc scientists (Oak Ridge, TN) in U.S. Patent Application 20100209706 describe a method of fabricating a fluffy nano-material and nanocatalysts.
According to inventors Paul A. Menchhofer, Roland D. Seals, Jane Y. Howe and Wei Wang.
at 2000.times. magnification the fluffy nanomaterial has the appearance of raw, uncarded wool, with individual fiber lengths ranging from approximately four microns to twenty microns. Powder-based nanocatalysts are dispersed in the fluffy nanomaterial. The production of fluffy nanomaterial typically involves flowing about 125 cc/min of organic vapor at a pressure of about 400 torr over powder-based nano-catalysts for a period of time that may range from approximately thirty minutes to twenty-four hours.
Nanostructures are objects that have physical dimensions between those of sub-atomic-scale (less than one Angstrom-sized) structures and microscopic-scale (greater than one tenth micrometer-sized) structures. Nanostructures are said to have nano-scale features. "Nano-scale" refers to a dimension that is between approximately one Angstrom (0.1 nanometer) and approximately 100 nanometers (0.1 micrometer). Nano-scale features may occur in one, two, or three dimensions.
For example, nano-textured surfaces have one nano-scale dimension. That is, such surfaces have nano-features such as ridges, valleys or plateaus that provide surface height variations that range from about 0.1 to about 100 nanometers. Another example of a one-dimension nanostructure is a film that has a thickness that ranges from about 0.1 to about 100 nanometers. Nanotubes are examples of nanostructures that have two nano-scale dimensions. That is, a nanotube has a diametral dimension and a length. The diametral dimension of a nanotube ranges from about 0.1 to about 100 nanometers. The length of a nanotube may be greater than hundreds of microns. Nanoparticles have three diametral nano-scale dimensions. Each diametral dimension of a nanoparticle ranges from about 0.1 to about 100 nm.
Nanostructures may be formed from carbon, silicon, boron, various metal and metalloid elements, various compounds, alloys and oxides of those elements, ceramics, various organic materials including monomers and polymers, and potentially any other material. Nanostructures have potential use in various physical, chemical, mechanical, electronic and biological applications. Nanomaterials are collections of nanostructures. The formation, collection, and assembly of nanomaterials generally involve difficult and expensive processes. One major issue with nanomaterials is the difficulty of production of the nanostructures in sufficient quantity, purity, and uniformity of morphology to be useful. What are needed therefore are better systems and methods for manufacturing nanomaterials.
In one embodiment the present disclosure provides a fluffy nanomaterial that includes a plurality of individual nanostructure fibers. The fluffy nanomaterial is characterized at approximately 2000.times. magnification as having the appearance of raw uncarded wool, with individual nanostructure fibers having lengths ranging from approximately four microns to approximately one centimeter. Further the fluffy nanomaterial has powder-based nanocatalysts dispersed therein.
Also disclosed is a method of manufacturing a fluffy nanomaterial that includes the following steps, which may be performed in any order. One step is heating powder-based nanocatalysts to about 500.degree. C. A second step is exposing the powder-based nanocatalysts to a flow of organic vapor at between about 125 cc/min and about 150 cc/min and at a process pressure of about between about 200 torr and about 400 torr for a time period ranging from about 30 minutes to about 24 hours to form the fluffy nanomaterial.
Nanostructures may be formed from carbon, silicon, boron, various metal and metalloid elements, various compounds, alloys and oxides of those elements, ceramics, various organic materials including monomers and polymers, and potentially any other material. Nanostructures have potential use in various physical, chemical, mechanical, electronic and biological applications. Nanomaterials are collections of nanostructures. The formation, collection, and assembly of nanomaterials generally involve difficult and expensive processes. One major issue with nanomaterials is the difficulty of production of the nanostructures in sufficient quantity, purity, and uniformity of morphology to be useful. What are needed therefore are better systems and methods for manufacturing nanomaterials.
In one embodiment the present disclosure provides a fluffy nanomaterial that includes a plurality of individual nanostructure fibers. The fluffy nanomaterial is characterized at approximately 2000.times. magnification as having the appearance of raw uncarded wool, with individual nanostructure fibers having lengths ranging from approximately four microns to approximately one centimeter. Further the fluffy nanomaterial has powder-based nanocatalysts dispersed therein.
Also disclosed is a method of manufacturing a fluffy nanomaterial that includes the following steps, which may be performed in any order. One step is heating powder-based nanocatalysts to about 500.degree. C. A second step is exposing the powder-based nanocatalysts to a flow of organic vapor at between about 125 cc/min and about 150 cc/min and at a process pressure of about between about 200 torr and about 400 torr for a time period ranging from about 30 minutes to about 24 hours to form the fluffy nanomaterial.
FIG. 10 is photomicrograph of fluffy nanomaterial, at two different magnifications.
FIG. 11 is a photograph of fluffy nanomaterial.
FIG. 11 is a photograph of fluffy nanomaterial.
Powder-based nano-catalysts may be used in various processes to produce nanostructures and nanomaterials. For example, powder-based nano-catalysts may be used to grow carbon nanotubes that may be harvested and used as nanomaterials. The powder-based nano-catalysts may also be incorporated as a constituent of components and coatings that then have catalytic properties for enhancing the formation of nanostructures within the component or the coating.
That is, instead of first fabricating and collecting nanostructures as nanomaterials and then mixing those nanomaterials with other constituents to form nanostructure-bearing composite materials, powder-based nano-catalysts may be mixed with other constituents and nanostructures may then be grown in-situ to form nanostructure-bearing composite materials. The term "in-situ" refers to a formation of nanostructures (e.g., carbon nanotubes) on individual powder particles that may subsequently be used to fabricate composite materials that incorporate the anchored nanostructure material, without transferring the nanostructures to another material or powder for such use. The nanostructure-bearing composite material may be formed as a layer that is disposed adjacent the surface of a component or the nanostructure-bearing composite material may be formed as a portion or all of the bulk material of the component.
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