Ferrocerium is a man-made metallic material that has the ability to give off a large number of hot sparks at temperatures at 3,000 °F (1,650 °C) when scraped against a rough surface (pyrophoricity), such as ridged steel. Because of this property it is used in many applications, such as clockwork toys, strikers for welding torches, so-called "flint-and-steel" fire-starters in emergency survival kits, and, perhaps most commonly, in butane-type lighters, as the initial ignition source for the primary fuel. What is commonly called "flint" in modern times is actually ferrocerium. Also known as Auermetall after its inventor Baron Carl Auer von Welsbach, it is sold under such trade names as Blastmatch, Fire Steel, and Metal-Match.
While ferrocerium-and-steels function in a similar way to actual flint-and-steel in fire starting, ferrocerium actually takes on the role that steel played in traditional methods: When small shavings of it are removed quickly enough the heat generated by friction is enough to ignite those shavings. The sparks generated are in fact tiny pieces of burning metal. In traditional flint-and-steel fire-starting systems (using actual flint), it is the tiny shavings of the steel removed in the striking process that burn, rather than the flint. The sparking is a result of cerium's low temperature pyrophoricity, its ignition temperature occurring between 150 and 180 degrees celsius.
Since smaller scrapings become better sparks, the mechanical properties of rare earth metals must be adjusted to give a usable material; to that end, at least two strategies have been developed to make such alloys more brittle:
There were actually three different Auermetalls developed: The first was just iron and cerium, the second also included lanthanum to produce brighter sparks, and the third added other heavy metals.
A modern ferrocerium firesteel product is composed of an alloy of rare earth metals called mischmetal (containing approximately 50% cerium, 25% lanthanum, and small amounts of neodymium and praseodymium), plus iron and a small amount of magnesium[1]:
Iron: 19%
Cerium: 38%
Lanthanum: 22%
Neodymium: 4%
Praseodymium: 4%
Magnesium: 4%
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