Spark plugs are at the centre of the ignition system on all petrol-based vehicles.

Some are copper cored as copper is a good conductor of electricity.

NONE have copper electrode tips, as they would burn out in about five minutes!

Some have steel electrodes, some platinum, and some iridium. Iridium is the best as far as longevity goes. Platinum has a lower melting point so it won't last as long.

Iridium can last between 75,000 to 100,000 miles in a car.

My Mazda (Miata) MX-5 Mk4 has an iridium centre electrode and a platinum ground electrode. See Pictire

I am English, so centre is spelt wrong, well because... English

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    Do you have a question? – Solar Mike Aug 5 '20 at 19:04
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    Btw, when one posts on here, one accepts how others spell words like tire & tyre and one does not inflict personal language preferences on others. so hood and bonnet, trunk and boot etc etc. – Solar Mike Aug 5 '20 at 19:06
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    I’m voting to close this question because it's not a question. – Pᴀᴜʟsᴛᴇʀ2 Aug 5 '20 at 22:07

Correcting some misinformation : The side electrode was never steel. It is Nichrome ( there are other names for the same alloy). Before platinum the center electrodes were also Nichrome. Platinum plugs last well over 100,000 miles in a normal car, maybe not in a race car .I have removed 16 platinum plugs with over 100.000 miles and they looked like new , no carbon,no erosion. ( 1998 Sienna and 2004 Titan). Subsequent operation with new platinum plugs showed no change in mileage or performance. Presently have 80,000 miles on 6 platinum plugs in a Murano, performance is excellent ( being old I don't run-up mileage as I previously did). Personally I would not pay an extra cent for spark plugs with rhodium ,iridium, osmium, etc.

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