Claims
- 1. A spark plug for an internal combustion engine, comprising:an insulation porcelain having a throughhole; a center electrode held at one end of the throughhole; a housing holding the insulation porcelain; a ground electrode disposed at a front end of the housing and facing the center electrode; a spark gap defined by the center electrode and the ground electrode; and at least one of the center electrode and the ground electrode having a noble metal member bonded to a discharging spot of a front end thereof, wherein the noble metal member consists of 90 wt % or more of an Ir—Rh alloy containing 1 to 60 wt % Rh and the balance substantially consisting of at least one of Pt, Pd, Ru, Au and Ni.
- 2. A spark plug as in claim 1, wherein the noble metal member consists of 90 wt % or more of an Ir—Rh alloy containing 3 to 30 wt % Rh.
- 3. A spark plug for an internal combustion engine, comprising:an insulation porcelain having a throughhole; a center electrode held at one end of the throughhole; a housing holding the insulation porcelain; a ground electrode disposed at a front end of the housing and facing the center electrode; a spark gap defined by the center electrode and the ground electrode; and at least one of the center electrode and the ground electrode having a noble metal member bonded to a discharging spot of a front end thereof, wherein the noble metal member consists of 90 wt % or more of an Ir—Rh alloy containing 1 to 60 wt % Rh and the balance substantially consisting of 0.5 to 5 wt % of an oxide of an element of the group 3A or 4A of the periodic table and at least one of Pt, Pd, Ru, Au and Ni.
- 4. A spark plug as in claim 3, wherein the noble metal member consists of 90 wt % or more of an Ir—Rh alloy containing 3 to 30 wt % Rh.
Priority Claims (1)
Number |
Date |
Country |
Kind |
7-148649 |
Jun 1995 |
JP |
|
Parent Case Info
This is a Continuation-in-Part of U.S. patent application Ser. No. 08/663,528 filed Jun. 13, 1996, now U.S. Pat. No. 6,094,000 which designated the U.S.
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Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
08/663528 |
Jun 1996 |
US |
Child |
08/933838 |
|
US |