My periodic table poster is now available! Spark plug. According to this interesting article about different elements in spark plugs these Autolite spark plugs use a chromium-nickel alloy for the ground electrodes, along with a platinum center electrode. ACDelco make a different plug that uses a silver-nickel alloy instead. Source: Auto Parts Store Contributor: Theodore Gray Acquired: 10 January, 2003 Text Updated: 11 August, 2007 Price: $5 Size: 3" Purity: <50% Sample Group: Spark Plugs