Patent Application
20130048337
The subject matter herein relates generally to carbon-based substrate (CBS) conductors, cables and other electrical components using CBS conductors and methods of manufacturing CBS conductors, cable or other electrical components using CBS conductors.
CBSs may include carbon nanotubes (CNTs), graphene or other carbon-based networks as the substrate. CBSs have use in a wide range of applications. Due to the electrical conductivity exhibited by CBSs, CBSs have application in electrical systems, such as use as electrical conductors of cables, wires or other conductors, as electromagnetic interference (EMI) shielding for cables or other types of electronic components, and other applications. Due to the relative light weight of CBSs, as compared to traditional metal components, CBSs have application in aeronautical application where weight is a significant design factor.
CBSs for use as electrical conductors are not without disadvantages. For instance, for some applications, the electrical conductivity of the CBS network is inadequate. A need remains for a CBS network that exhibits good electrical characteristics.
In one embodiment, a cable is provided having a jacket surrounding a core and a carbon-based substrate (CBS) conductor in the core. The CBS conductor includes a CBS network and an organometallic filler, wherein the organometallic filler combines with the CBS network to form a composite conductor having a higher conductivity than the CBS network. Optionally, the CBS network may include carbon nanotube (CNT) fibers with the organometallic fillers being disposed between the CNT fibers. The organometallic fillers may include at least one of palladium glycolate, glycolic acid, glyoxyllic acid or methanol. The CBS network may be a yarn, a sheet, or a tape. Optionally, the organometallic filler may be applied to the CBS network as a solution that is decomposed under heat to create the composite conductor. The CBS network may be bathed in an organometallic bath to react the organometallic filler with the CBS network. The organometallic filler may be introduced as an organometallic bath having a solvent and organometallic particles in solution, where the solvent is heated to remove the solvent from the composite conductor leaving the reacted organometallic particles on the CBS network. The CBS network and the organometallic fillers may be densified to create the composite conductor.
Optionally, the cable may include a plurality of the CBS conductors twisted along a length of the cable to form a central conductor of the cable. The CBS conductor may surround the core and provide EMI shielding for the core. The cable may be a coaxial cable having an insulator and a second CBS conductor in the core with the insulator surrounding the CBS conductor, the second CBS conductor surrounding the insulator and the jacket surrounding the second CBS conductor. The second CBS conductor may provide EMI shielding for the other CBS conductor, which may be configured to convey electrical signals between a first end and a second end of the cable.
In another embodiment, a method for manufacturing a carbon-based substrate (CBS) conductor is provided that includes providing a CBS network of CBS fibers forming a framework, introducing an organometallic compound, and reacting the CBS network with the organometallic compound to form a composite conductor. The method may include immersing the CBS network in an organometallic bath having organometallic particles in a solvent. The reacting may include heating the composite conductor to remove the solvent leaving behind the converted organometallic particles. The method may include annealing the composite conductor and/or densifying the composite conductor by heating and cooling the composite conductor. The method may include extracting CBS fibers from a CBS array to form the framework having a shape of one of a yarn, a tape or a sheet. The method may include forming the composite conductor into a cable during a cable forming process.
The EMI shield 106 and the center conductor 110 are electrically conductive. The cable 100 defines a coaxial cable having the center conductor 110 and an outer conductor defined by the EMI shield 106 extending along a common axis along the length of the cable 100. The cable 100 may be another type of cable, such as a twin-axial cable, a quad-axial cable, an unshielded cable, and the like. The center conductor 110 is configured to convey electrical signals between a first end 112 (shown in
In an exemplary embodiment, the center conductor 110 and the EMI shield 106 are manufactured from a carbon-based substrate (CBS), such as carbon nanotubes (CNTs), graphene, a graphite oxide structure, and the like. Alternatively, the center conductor 110 and the EMI shield 106 are manufactured from another nano-substrate, such as a ceramic nanowire, such as a boron nitride substrate. The CBS-based network may be modified to create other types of electronic components such as a passive dielectric or insulating component. The CBS-based network may be modified to make other compounded/composite surfaces.
The center conductor 110 defines a CBS conductor, and may be referred to hereinafter as a CBS conductor 110. Optionally, the center conductor 110 may include one or more strands of CBS conductors that are twisted together during a cable forming process. The EMI shield 106 defines a CBS conductor, and may be referred to hereinafter as a CBS conductor 106. In an alternative embodiment, only the center conductor 110 is manufactured from a CBS network. In another alternative embodiment, only the EMI shield 106 is manufactured from a CBS network.
In an exemplary embodiment, each CBS conductor 106, 110 is manufactured from a CBS network that is combined with organometallic fillers to form a composite conductor. The organometallic fillers may include compounds containing metal-element bonds that are between ionic and covalent in character. The organometallic fillers may at least partially permeate through, or be infused into, the CBS network and/or the individual fibers or yarns, or alternatively, may be a coating surrounding an outer surface of the CBS network. The CBS network may be a CNT network, a graphene network or another carbon-based network. In an exemplary embodiment, the organometallic fillers are organopalladium compounds, such as palladium glycolate. Other types of compounds or fillers may be used in alternative embodiments. The organometallic fillers may include glycolic acid, glyoxyllic acid, methanol, and the like. The type of base metallic compound used for the organometallic compound is selected to enhance certain characteristics of the CBS network, such as the electrical characteristics of the CBS network.
In an exemplary embodiment, the organometallic fillers are applied by bathing the CBS network in an organometallic bath that includes a solvent and the organometallic particles in the solution. The composite conductor is then processed to remove the solvent and/or react the organometallic with the CBS network. For example, the composite conductor may be subjected to heating, cooling, annealing, densifying, thickening, winding, plying, braiding, functionalizing and the like. The organometallics may be applied by other processes in alternative embodiments, such as physical vapor deposition, chemical vapor deposition, dip coating, or other processes to apply the organometallics to the CBS network.
In an exemplary embodiment, each strand 132 is a separate CBS conductor manufactured from a CBS network 134 that is combined with organometallic fillers 136. The organometallic fillers 136 may extend or permeate entirely through the CBS network 134 such that the organometallic fillers 136 are between the fibers of the CBS network. The organometallic fillers may be both a coating between individual fibers or yarns in a network or braid, and penetrate the fibers or yarns that makes up the network or braid.
The first and second electrical components 116, 118 are represented schematically in
In an exemplary embodiment, the CBS network of the CBS conductor is conductive and is configured to convey electrical signals between the first and second electrical components 116, 118. The organometallic fillers may enhance the electrical properties of the center conductor 110 and/or EMI shield 106. For example, the conductivity of the CBS-based center conductor 110 and/or EMI shield 106 may be increased by selecting an organometallic material having a high conductivity.
In an exemplary embodiment, the framework 152 may be pulled or drawn from a CBS array or CBS source, such as by using a spinning technique. The framework 152 may be formed into a yarn or wire. The framework 152 may be a braided yarn or a mesh. Alternatively, the framework 152 may be formed into a tape. Alternatively, the framework 152 may be formed into a sheet. The wire, tape or sheet may have any length depending on the particular application. A wire is defined as having a width that is less than approximately two times a thickness of the framework 152. A tape is defined as having a width that is greater than approximately two times the thickness of the framework 152 and having a width that is less than approximately ten times the thickness of the framework 152. A sheet is defined as a framework having a width that is greater than approximately ten times the thickness of the framework 152. The framework 152 may have different shapes depending on the particular application.
The wires or yarns may be used, for example, to define the strands of the center conductor 110 (shown in
During manufacture, CBS fibers are pulled or otherwise extracted from the CBS array 200 by the drawing module 202 to make a framework or CBS network. The CBS network may be taken in the form of a wire or yarn, a tape, a sheet and the like. The CBS network is bathed in the solvent bath 204. The CBS network is bathed in the organometallic bath 206. Optionally, the CBS network is bathed in the solvent bath 204 prior to the organometallic bath 206. Alternatively, the CBS network is bathed in the organometallic bath 206 prior to the solvent bath 204. In other alternative embodiments, the CBS network is not bathed in the solvent bath 204, but rather is only bathed in the organometallic bath 206. The solvent bath 204 may include non-organometallic materials, such as metal particles, that are coated or infused into the CBS network to enhance the characteristics of the composite conductor. The composite conductor, with the CBS network, the non-organometallic particles and/or the organometallic fillers, is then directed to the densification module 208. The CBS network is densified, such as by spinning or otherwise densifying the CBS network. The CBS conductor is directed to the post-processing module 210. At the post-processing module 204 the CBS conductor may be subjected to heating, cooling, winding, plying, braiding, shrinking, twisting, doping, densification, pressing, forming or other processes to affect the interaction between the CBS fibers and the organometallic fillers and/or the non-organometallic fillers and/or to define a shape of the CBS conductor.
The CBS conductor is directed to the cable forming module 212 to form a cable, such as the cable 100 (shown in
In alternative embodiments, rather than using the CBS conductors to form cables, the CBS conductors may be used to form other electrical components, such as an electrical connector, a processor, a circuit board, or another electrical component. The CBS conductor may be used as part of a signal conductor or alternatively may be part of an EMI shield or another part of an electrical component.
The method includes post-processing 256 the organometallic CBS network. For example, the post processing may include heating, cooling, winding, plying, braiding, shrinking, twisting, doping, densifying, pressing, forming or performing other processes to affect the interaction between the CBS fibers and the organometallic fillers and/or to define a shape of the CBS conductor. In an exemplary embodiment, the organometallic includes a palladium compound, where the palladium compound is heated to react and/or convert the palladium with the CBS network.
The method includes incorporating 258 the organometallic CBS network into a cable. For example, the organometallic CBS network may be presented to a cable forming machine that pulls the organometallic CBS network into a cable form within a jacket.
The organometallic CBS network may be used in other types of electrical systems other than a cable, such as an electrical connector, a microprocessor, or another type of electrical component. Any application suitable for use with CBSs may utilize the organometallic CBS conductor. The addition of organometallics with the CBS network enhances the characteristics of the CBS network, such as electrically by increasing the conductivity of the CBS network.
The chart shows conductivity measurements for a first untreated CBS conductor 280, which is a CNT tape, a second untreated CBS conductor 282, which is also a CNT tape, and a third untreated CBS conductor 284, which is a CNT yarn. Variations in the conductivity of the untreated CBS conductors 280, 282, 284 are observable, with the conductivity of the first untreated CBS conductor 280 being approximately 500 (ohms-cm)−1, the conductivity of the second untreated CBS conductor 282 being approximately 200 (ohms-cm)−1, and the conductivity of the third untreated CBS conductor 284 being approximately 50 (ohms-cm)−1.
The chart shows conductivity measurements for a first organometallic CBS conductor 290, which is the first CBS conductor 280 after having an organometallic, in this embodiment being palladium glycolate, applied to the CBS network. The chart also shows a second organometallic CBS conductor 292, which is the second CBS conductor 282 after having an organometallic, in this embodiment being palladium glycolate, applied to the CBS network. The chart also shows a third organometallic CBS conductor 294, which is the third CBS conductor 284 after having an organometallic, in this embodiment being palladium glycolate, applied to the CBS network. The conductivity of the organometallic CBS conductors 290, 292, 294 is considerably higher than the corresponding untreated CBS conductors 280, 282, 284, respectively. The conductivity of the first organometallic CBS conductor 290 is approximately 1300 (ohms-cm)−1, the conductivity of the second organometallic CBS conductor 292 is approximately 1100 (ohms-cm)−1, and the conductivity of the third organometallic CBS conductor 294 is approximately 1500 (ohms-cm)−1.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
