Granted Patent B2

US 12,308,619 · App. 17/793,826 · Granted May 20, 2025

Inventors: Osamu Yoshimoto (Nagoya, JP); Tomoo Tanaka (Nagoya, JP); Kengo Hattori (Nagoya, JP)

Assignee: NGK SPARK PLUG CO., LTD.

H01T13/39C22C5/04

Abstract

Claims (12)

1. A noble metal tip for a spark plug comprising:

iridium (Ir) in an amount of 50 mass % or more; aluminum (Al) in an amount of 0.1 mass % or more and 5 mass % or less; and

rhodium (Rh),

wherein a metallographic structure comprised of fiber-like elements, the fiber-like elements of the metallographic structure having an average aspect ratio of 150 or more and have an average length of 25 μm or less in a minor axis direction.

2. The noble metal tip for spark plug according to claim 1 , which contains rhodium (Rh) in an amount of 3 mass % or more and less than 30 mass %.

3. The noble metal tip for spark plug according to claim 1 , which further contains at least one of ruthenium (Ru) and nickel (Ni).

4. The noble metal tip for spark plug according to claim 3 , which contains ruthenium (Ru) in an amount of 3 mass % or more and less than 20 mass % and/or nickel (Ni) in an amount of 0.1 mass % or more and less than 5 mass %.

5. The noble metal tip for spark plug according to claim 1 , which has a film formed on a surface of the tip and containing aluminum oxide.

6. A spark plug in which at least one of a center electrode and a ground electrode has a noble metal tip for spark plug according to claim 5 ,

wherein the film is provided at least on a discharge surface of the noble metal tip for spark plug.

7. An electrode for a spark plug, comprising a noble metal tip for spark plug according to claim 1 .

8. A spark plug comprising an electrode for spark plug according to claim 7 .

Assignments (2)

Priority Claims (1)

Continuity (1)

References Cited (10)