Patent ID: 6846214
Filing Date: 2005-01-25
Classification: H01T

Abstract:
1. A method of manufacturing a spark plug for an internal combustion engine, the spark plug including an insulator having a through-hole formed therein, a center electrode made of a nickel-based alloy disposed at one end of the through-hole, a metal housing holding the insulator therein, and a ground electrode connected to the metal housing and disposed to face the center electrode, forming a spark gap therebetween, the manufacturing method comprising steps of: attaching a noble metal chip directly on a flat end surface of the center electrode, the noble metal chip being made of an iridium alloy containing iridium and a noble metal having a melting point in a range from 1,500 to 2,100° C. and a linear expansion coefficient in a range from 8×10 radiating a laser beam on the noble metal chip in a direction substantially perpendicular to an axial direction of the center electrode, thereby forming a molten bond containing more than 1-weight-percent noble metal having a melting point in a range from 1,500 to 2,100° C. and a linear expansion coefficient in a range from 8×10 wherein the laser is a Yag laser, and wherein the Yag laser energy is in a range of 5.0 J-10.0 J.