Mischmetal

Misch metal and the cerium mixed metal, a metal alloy made of rare earth metals. Standard qualities consist typically to at least 98 % of rare earth metals, 1 % iron and 0.8 % magnesium.

Since the rare earth metals are separated only very costly because of their great chemical similarity, mixed metal is cheaper than any one of these elements and, if possible, preferably used.

The percentage distribution of rare earth metals in the classical mixed metal stems directly from that of the starting mineral monazite: it contains about 45 to 52% cerium, 20 to 27 % lanthanum, 15 to 18 % neodymium, 3 to 5% praseodymium, 1 to 3% samarium, terbium and yttrium, traces of other rare earth metals. Because of today's high demand for neodymium for the preparation of neodymium-iron- boron magnets are now, however, this and most separated the elements samarium and the following, so that present-day mixed metal usually only the rare earth metals cerium, lanthanum and some praseodymium contains. Due to the similarity in the chemical properties of the rare earths are variations in the composition - in applications for any mixed metal can be used - usually not critical.

Iron - mischmetal alloys with an iron content of 15 % to 50% is referred to as cerium or mischmetal with the trade name.

As an additive in steel making mixed metal reduces unwanted iron oxides, it binds oxygen and sulfur, and supports the degassing. A metal alloy, it improved the casting and flow properties and the corrosion resistance of iron-chromium- aluminum materials in hot oxidizing gases.

Additions of cerium mixed metal improve the mechanical properties of cast iron with nodular graphite, by compensating for the negative effects of so-called disturbing elements to the formation of graphite.

The Austrian chemist Carl Auer von Welsbach discovered the pyrophoric properties of iron mixed metal alloys (Patent 1903). Filings ignite on contact with air - a property that is exploited for the manufacture of flints for lighters. In which he had founded " Auer works" ( now Treibacher Industrie AG ) today flints are manufactured under the trade name Auermetall.