Patent ID: 8946976
Filing Date: 2015-02-03
Classification: H01T

Abstract:
1. A spark plug, comprising: a cylindrical metal shell; a ground electrode joined to a front end portion of the metal shell; and a nickel layer formed on the ground electrode, wherein the ground electrode has a base material exposed region in which a base material of the ground electrode is exposed; and wherein the nickel layer includes at least an outer-lateral-side nickel layer located on an outer lateral surface of the ground electrode so as to be adjacent to the base material exposed region of the ground electrode and satisfies a condition of LA≧25 μm, where LA is a length from a first part of the outer-lateral-side nickel layer having a thickness equal to 80% of a maximum thickness of the outer-lateral-side nickel layer to a second part of the outer-lateral-side nickel layer having a thickness equal to 20% of the maximum thickness of the outer-lateral-side nickel layer in a longitudinal direction of the ground electrode.