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A spark plug 20 includes a center electrode 22 and a ground electrode 24 providing a spark gap 26 therebetween. At least one of the electrodes 22, 24, but preferably both electrodes 22, 24 include a clad surrounding a core. The clad includes at least one metal, such as nickel, iron, or cobalt. The c

A spark plug 20 includes a center electrode 22 and a ground electrode 24 providing a spark gap 26 therebetween. At least one of the electrodes 22, 24, but preferably both electrodes 22, 24 include a clad surrounding a core. The clad includes at least one metal, such as nickel, iron, or cobalt. The core includes nanocarbon material embedded in a copper matrix 40 to increase the thermal conductivity and reduce the coefficient of thermal expansion of the core. The nanocarbon material includes a plurality of fibers 42, also referred to as particles, whisks, or tubes, each having a diameter of 1.0 to 150.0 nanometers and a length of 1 μm to 100 μm. The core includes the nanocarbon material in an amount of 0.1 to 10.0 wt. %.

대표청구항 ▼

1. A spark plug comprising: a center electrode and a ground electrode presenting a spark gap therebetween;at least one of said electrodes including a clad and a core, wherein said clad surrounds said core, said clad is formed of at least one metal, and said core includes a matrix of copper or a copp

1. A spark plug comprising: a center electrode and a ground electrode presenting a spark gap therebetween;at least one of said electrodes including a clad and a core, wherein said clad surrounds said core, said clad is formed of at least one metal, and said core includes a matrix of copper or a copper alloy; andsaid core including a nanocarbon material embedded in said matrix. 2. The spark plug of claim 1 wherein said nanocarbon material includes at least one sheet of carbon atoms extending circumferentially around a center axis. 3. The spark plug of claim 1 wherein said sheet is a mesh of said carbon atoms spaced from one another and presenting a plurality of interconnected hexagonal shapes. 4. The spark plug of claim 1 wherein each of said nanocarbon materials have a diameter of 1.0 to 150.0 nanometers. 5. The spark plug of claim 1 wherein each of said nanocarbon materials have a length of 1 μm to 100 μm. 6. The spark plug of claim 1 wherein said at least one electrode including said nanocarbon material further includes an outer surface, and wherein said nanocarbon material extends parallel to said outer surface. 7. The spark plug of claim 1 wherein said at least one electrode including said nanocarbon material further includes an outer surface, and wherein said nanocarbon material extends at angles relative to said outer surface. 8. The spark plug of claim 1 wherein said core has a thermal conductivity of 400 to 600 W.m/K. 9. The spark plug of claim 1 wherein said clad has a coefficient of thermal expansion of 11 to 13×10−6/K. 10. The spark plug of claim 1 including an insulator disposed annularly around said center electrode. 11. The spark plug of claim 1 wherein said copper matrix has a coefficient of the thermal expansion greater than a coefficient of thermal expansion of said clad. 12. The spark plug of claim 1 wherein said clad includes at least one of nickel, iron, and cobalt. 13. The spark plug of claim 1 wherein said center electrode and said ground electrode both include said clad and said core with a nanocarbon material embedded in said copper matrix. 14. The spark plug of claim 1 wherein said nanocarbon material includes a plurality of fibers, particles, whisks, or tubes. 15. A method of forming a spark plug comprising the steps of: providing at least one of a center electrode and a ground electrode with a clad and a core, wherein the clad surrounds the core, the clad is formed of at least one metal, the core includes a matrix of copper or a copper alloy; and the core includes a nanocarbon material embedded in a copper matrix. 16. The method of claim 15 including embedding the nanocarbon material in the copper matrix. 17. The method of claim 15 including aligning the nanocarbon material with an outer surface of the electrode. 18. A spark plug comprising: a center electrode including a center body extending longitudinally along a central electrode axis from an center terminal end to a center firing end;said center body including a center outer surface extending circumferentially around and parallel to said center electrode axis and extending continuously from said center terminal end to said center firing end;said center body including a center clad surrounding a center core;said center clad including at least one of a nickel, iron, and cobalt;said center core including a copper matrix formed of copper or a copper alloy;said copper or copper alloy of said copper matrix including pure copper or oxygen-free copper;said copper matrix having a coefficient of thermal expansion greater than the coefficient of thermal expansion of said center clad;said copper matrix having a thermal conductivity of at least 350 W/(m·K);said center core including nanocarbon material embedded in said copper matrix;said nanocarbon material including a plurality of fibers, each fiber including at least one sheet of carbon atoms extending circumferentially around a center axis, said sheet being a mesh of said carbon atoms spaced from one another to present a plurality of interconnected hexagonal shapes;each of said fibers having a diameter of 1.0 to 150.0 nanometers;each of said fibers having a length of 1 μm to 200 μm;each of said fibers having a tensile strength of 10 to 150 GPa;each of said fibers having a thermal conductivity of 400 to 600 W.m/K;each of said fibers having a coefficient of thermal expansion of 2.7×10−6 to 4.6×10−6 W.m/K;said center core including said nanocarbon material in an amount of 0.1 to 10.0 wt. %, based on the total weight of said center core;said center core having a thermal conductivity of 400 to 600 W.m/K;said center electrode including a center spark tip disposed on said center firing end and presenting a center spark surface;said center spark tip including at least one precious metal;an insulator formed of an electrically insulating material disposed annularly around said center outer surface and extending longitudinally along said center outer surface from an insulator top end to an insulator nose end;said insulating material including alumina;said insulator extending longitudinally past said center terminal end and toward said center firing end such that said center firing end extends outwardly of said insulator nose end;said insulator including an insulator outer surface extending continuously from said insulator top end to said insulator nose end and an oppositely facing insulator inner surface engaging said center outer surface;a shell formed of a metal material disposed annularly around said insulator outer surface and extending longitudinally along said insulator outer surface from a shell upper end to a shell lower end;a ground electrode including a ground body extending from said shell lower end toward said center spark surface and to a ground firing end;said ground body including a ground outer surface extending circumferentially around a ground electrode axis and continuously from said shell lower end to said ground firing end;said ground electrode axis curving from said shell lower end toward said center spark surface;said ground body including a ground clad surrounding a ground core;said ground clad including at least one of a nickel, iron, and cobalt; andsaid ground core including said nanocarbon material embedded in said copper matrix.