Title:
WEAR-RESISTANT SPARK PLUG ELECTRODE TIP CONTAINING PLATINUM ALLOYS, SPARK PLUG CONTAINING THE WEAR-RESISTANT TIP, AND METHOD OF MAKING SAME
Document Type and Number:
WIPO Patent Application WO2000003463
Kind Code:
A9
Abstract:
A wear-resistant electrode tip for a spark plug, and a spark plug which incorporates the wear-resistant tip. The wear-resistant tip includes an alloy of platinum, iridium, and tungsten. Surprisingly by addition of a small amount of tungsten to platinum-iridium alloy, the wear-resistance of a resultant spark plug is greatly improved. The spark plug electrode tip according to the invention is either spherical or rivet-shaped. During manufacture, the spark plug electrode tip is annealed in an annealing furnace. The annealing furnace is preferably either charged with an inert gas such as argon or nitrogen, or is subjected to a vacuum. The electrode tip is, optionally, further externally coated with platinum or a compatible bonding metal alloy before attachment to the electrode. Subsequent to annealing and, where used, to external coating, the spark plug electrode tip is placed in a welding fixture. The tip is then aligned with a spark plug electrode and is resistance welded thereto. Similar procedures are preferably performed on both the center and side electrodes of the spark plug. The annealed spark plug electrode tips using the novel alloys according to the invention have a high resistance to attack by lead and other corrosive elements typically present in the combustion chambers of internal combustion engines. A preferred method of making a wear-resistant spark plug is also disclosed.
Inventors:
CHANG CHIN-FONG
TAYLOR RICHARD DALE
FRANZ LEE RANDALL
LEONE EDGAR ARNOLD
KOZLOV ALEXANDRE SEGEEVICH
TAYLOR RICHARD DALE
FRANZ LEE RANDALL
LEONE EDGAR ARNOLD
KOZLOV ALEXANDRE SEGEEVICH
Application Number:
PCT/US1999/015770
Publication Date:
March 23, 2000
Filing Date:
July 13, 1999
Export Citation:
Assignee:
ALLIED SIGNAL INC (US)
International Classes:
C22C5/04; C22F1/00; C22F1/14; H01T13/39; H01T21/02; (IPC1-7): H01T13/39; H01T21/02
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