Cerium-iron alloy spark

To assess the overall thermal sensitivity of an energetic material in Germany, a number of tests related to the ignition towards standard ignition sources such as cerium-iron alloy sparks, bickford fuse flame jet, gas flames, red hot steel bar and match flame are conducted. In addition, the response of the material towards ignition under various levels of enclosure is tested, the so-called Koenen test [17]. 

The metals themselves are very electropositive, and are accordingly difficult to prepare. Electrolytic reduction of a fused oxide-fluoride mixture may be used. An alloy containing about 70% cerium and smaller amounts of other lanthanons and iron gives sparks when scratched. This alloy is widely used for cigarette lighters and gas lighters. 

Cerium forms with iron a peculiar pyrophoric alloy which, when struck, emits showers of sparks, and which is used somewhat m the manufacture of automatic gas-hghters (28). 

An interesting stage in the development of primer mixes was the use of pyrophoric metal alloys, first patented in 1936 and improved in 1964. These rare earth alloys, as used in cigarette lighter flints, give a shower of sparks when lightly scraped. A typical pyrophoric alloy is misch metal, which has the following approximate composition cerium 50%, lanthanum 40%, other rare earth elements 3%, and iron 7%. 

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