公开(公告)号：US20210203135A1

公开(公告)日：2021-07-01

申请号：US17132331

申请日：2020-12-23

Applicant: DENSO CORPORATION

Inventor： Masamichi SHIBATA ,  Hiroshi NAKAO

IPC: H01T13/39 ,  H01T21/02

Abstract: In a spark plug, a noble metal tip includes an Ir-alloy material and has a circular-columnar shape that has a predetermined outer diameter and is formed by the Ir-alloy material being stretched. The spark plug generates discharge between the noble metal tip and a ground electrode that is arranged to oppose an outer peripheral surface of the noble metal tip. The Ir-alloy material includes crystal grains of an Ir alloy having an average aspect ratio that is adjusted to be equal to or greater than 1.3 and equal to or less than 4.8. The average aspect ratio is an average value of aspect ratios of the crystal grains each being a value obtained by a length of the respective crystal grains in an axial direction of the noble metal tip being divided by a length of the respective crystal grains in a direction perpendicular to the axial direction.