Fine Wire Center Electrode Ensures High Durability and a Consistently Stable Spark
Iridium is a precious metal that is 6x harder and 8x stronger than platinum, has a melting point 1,200°(F) higher, and conducts electricity better.
For many years, spark plug manufacturers have favored platinum for their long life and performance plugs due to its high melting point. However, increasingly strenuous engine conditions, and the creation of smaller electrodes and longer life plugs requires harder and stronger metals. The strength, hardness and high melting point of iridium makes it very well suited for a fine wire plug and for ultra long life spark plugs.
Though better than platinum, it is very expensive, and at higher temperatures it oxidizes, thus rendering pure iridium as an expensively poor choice for spark plug construction. However, when properly blended with other precious metals such as Yttria, Rhodium or Platinum, you can enhance their advantages with the superior strength and hardness of Iridium.
Almost all manufacturers have their own version of an iridium spark plug. Do not be fooled, iridium plugs were not created equal. Iridium content varies. Some of the lower priced iridium plugs have just enough iridium content so they can be marketed as iridium plugs. They likely will not perform or last as long as the plugs with a higher iridium content.