Platinum tipped center and ground electrode
Platinum tipped ground with fine wire platinum center electrode
Platinum Coating on an oxygen sensor
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PLATINUM'S USE IN SPARK PLUG CONSTRUCTION
Nearly all spark plug manufacturers use platinum in one form or another on their long life or performance spark plugs. This is because of platinum’s high melting point, which makes it useful in two ways. On long life spark plugs a thin wafer of platinum is bonded at the firing point to the center electrode (and possibly ground electrode) solely so they don’t wear as fast as a traditional plug. On a fine wire performance plug, the very tip of the center electrode is made of platinum so that the fine wire tip will last longer. Do not be fooled, all platinum plugs are not created equal. Platinum is a very expensive precious metal, a $2 platinum spark plug will not have much platinum in it, and therefore will not last as long as a $12 platinum spark plug. Some platinum plugs have only the center electrode tipped with platinum, while others have both the center and ground electrodes platinum tipped. (It is not suggested that platinum plugs be used on vehicles with nitrous injection, however, there have been no problems reported using iridium plugs with nitrous).
PLATINUM'S USE IN OXYGEN SENSOR CONSTRUCTION
Platinum is used in the interior construction of an oxygen sensor. On a zirconia type sensor, a minute voltage is generated as oxygen ions pass through the sensor element. As they pass, they deposit a charge on the platinum coated electrode thus generating the voltage signal. The thin platinum coating then carries this signal (voltage) from the zirconia element to the lead wire and on to the ECU.
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