Patent ID: 7336024
Filing Date: 2008-02-26
Classification: H01T

Abstract:
1. A spark plug comprising: a center electrode; an insulator having an axial hole extending in an axial direction of said center electrode, holding said center electrode inside said axial hole; a metal shell surrounding said insulator to hold said insulator therein; a ground electrode including a first end portion bonded to said metal shell and a second end portion opposed to said center electrode; and a noble metal tip bonded to at least one of a front-end portion of said center electrode and said second end portion of said ground electrode, wherein said noble metal tip comprises: from 5 to 40 wt % of Rh; from 5 to 20 wt % of at least one of Ir, Re and Ru; from 0.2 to 3 wt % of Ni; and from 59 to 86 wt % of Pt.