# US 2008/0185948 A1 · Spark plug electrode and process for making > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0185948 A1 - Document ID: US20080185948A1 - Status: Published application - Kind: A1 - Application number: 11/670,790 - Filed: 2007-02-02 - Published: 2008-08-07 - Earliest claimed: 2007-02-02 - Assignees: Federal-Mogul Worldwide, Inc. - Inventors: Warran B. Lineton - Web page: https://patentgrep.com/patent/US20080185948A1 ## CPC - H01T 13/32: characterised by features of the earthed electrode - H01T 13/39: Selection of materials for electrodes - H01T 21/02: of sparking plugs - H01T: SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES (overvoltage protection circuits H02H) ## Abstract A spark plug and method for making. The spark plug comprises a center electrode, an insulator surrounding the center electrode, and a metallic shell surrounding the insulator. The spark plug also includes a ground electrode engaged with the metallic shell. The ground electrode has a first surface facing the center electrode for defining a spark gap and a second surface opposite the first surface. A cross-section of the ground electrode between the first and second surfaces includes a first zone of a non-noble metallic base material extending a distance from the second surface toward the first surface and a second zone of a blend of the non-noble base material and a noble metallic material extending from the first zone to the first surface. A method of making the spark plug includes the step of disposing a quantity of noble metallic material on an electrode blank formed of a non-noble metallic base material. The method also includes the step of at least partially melting the quantity of noble metal with a beam emitted by a laser. The method also includes the step of sequentially moving the laser along the electrode blank in first and second opposite directions to enhance the distribution of the molten quantity of noble metal over the electrode blank. ## Claims ### Claim 1 A spark plug comprising: a center electrode; an insulator surrounding said center electrode; a metallic shell surrounding said insulator; and a ground electrode engaged with said metallic shell and having a first surface facing said center electrode for defining a spark gap and a second surface opposite said first surface, wherein a cross-section of said ground electrode between said first and second surfaces includes a first zone of a non-noble metallic base material extending a distance from said second surface toward said first surface and a second zone of a blend of said non-noble base material and a noble metallic material extending from said first zone to said first surface. ### Claim 2 (depends on 1) The spark plug of claim 1 wherein quantities of both of said non-noble metallic base material and said noble metallic material are disposed at said first surface. ### Claim 3 (depends on 1) The spark plug of claim 1 wherein a gradual transition occurs between said first and second zones with respect to material composition between said non-noble metallic base material and said blend of said non-noble metallic base material and said noble metallic material. ### Claim 4 (depends on 1) The spark plug of claim 1 wherein a boundary between said first and second zones is irregular. ### Claim 5 (depends on 1) The spark plug of claim 1 wherein said non-noble metallic base material is further defined as including at least one of nickel, iron and chromium. ### Claim 6 (depends on 5) The spark plug of claim 5 wherein said non-noble metallic base material is further defined as an alloy including nickel, iron and chromium. ### Claim 7 (depends on 1) The spark plug of claim 1 wherein said noble metallic material is further defined as iridium. ### Claim 8 (depends on 1) A method of forming a spark plug electrode with a noble metal tip according to claim 1 comprising the steps of: disposing a quantity of noble metallic material on an electrode blank formed of a non-noble metallic base material; at least partially melting the quantity of noble metal with a beam emitted by a laser; and sequentially moving the laser and the electrode blank relative to one another in first and second opposite directions to enhance the distribution of the molten quantity of noble metal over the electrode blank. ### Claim 9 (depends on 8) The method of claim 8 further comprising the step of: varying an output of the laser during each sequential movement of said sequentially moving step. ### Claim 10 (depends on 8) The method of claim 8 wherein said disposing step includes the step of: applying a slurry containing the quantity of noble metallic material to the electrode blank formed of a non-noble metallic base material. ### Claim 11 (depends on 8) The method of claim 8 wherein said disposing step includes the step of: applying a slurry containing the quantity of noble metallic material to the electrode blank formed of a non-noble metallic base material prior to each sequential movement of said sequentially moving step. ### Claim 12 (depends on 8) The method of claim 8 wherein said at least partially melting step includes the steps of: pulsing a beam of the laser during a first sequential movement of said sequentially moving step; and continuously emitting the beam of the laser during a second sequential movement of said sequentially moving step. ### Claim 13 (depends on 1) A method of forming a spark plug electrode with a noble metal tip according to claim 1 comprising the steps of: applying a first quantity of noble metallic material in a slurry to an electrode blank formed of a non-noble metallic base material; drying the first quantity of noble metallic material to eliminate a liquid carrier in the slurry; directing a beam of a laser to melt the first quantity of noble metallic material; moving the laser and the electrode blank relative to one another in a first direction to move the beam along the first quantity of noble metallic material during said directing step; pulsing the beam during said step of moving the laser and the electrode blank relative to one another in the first direction; applying a second quantity of noble metallic material in a slurry to the electrode blank over the first quantity of noble metallic material after said moving step; drying the second quantity of noble metallic material to eliminate a liquid carrier in the second quantity of slurry; directing the beam of the laser to melt the second quantity of noble metallic material; moving the laser and the electrode blank relative to one another in a second direction opposite the first direction to move the beam along the second quantity of noble metallic material during said step of directing the beam of the laser to melt the second quantity of noble metallic material; and continuously applying the beam during said step of moving the laser and the electrode blank relative to one another in the second direction.