US 12,308,619 B2
Noble metal tip for spark plug, electrode for spark plug, and spark plug
Osamu Yoshimoto, Nagoya (JP); Tomoo Tanaka, Nagoya (JP); and Kengo Hattori, Nagoya (JP)
Assigned to NGK SPARK PLUG CO., LTD., Nagoya (JP)
Appl. No. 17/793,826
Filed by NGK SPARK PLUG CO., LTD., Nagoya (JP)
PCT Filed Feb. 2, 2021, PCT No. PCT/JP2021/003667
§ 371(c)(1), (2) Date Jul. 19, 2022,
PCT Pub. No. WO2021/161845, PCT Pub. Date Aug. 19, 2021.
Claims priority of application No. 2020-023207 (JP), filed on Feb. 14, 2020.
Prior Publication US 2023/0119721 A1, Apr. 20, 2023
Int. Cl. C22C 5/04 (2006.01); H01T 13/39 (2006.01)
CPC H01T 13/39 (2013.01) [C22C 5/04 (2013.01)] 8 Claims
OG exemplary drawing
 
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.