Ferrocerium
Encyclopedia
Ferrocerium is a man-made metallic material that has the ability to give off a large number of hot sparks at temperatures at 3000 °F (1,648.9 °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
toy
s, 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 name
s 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
:
Iron
: 19%
Cerium
: 38%
Lanthanum
: 22%
Neodymium
: 4%
Praseodymium
: 4%
Magnesium
: 4%
Pyrophoricity
A pyrophoric substance is a substance that will ignite spontaneously in air. Examples are iron sulfide and many reactive metals including uranium, when powdered or sliced thin. Pyrophoric materials are often water-reactive as well and will ignite when they contact water or humid air...
), such as ridged steel. Because of this property it is used in many applications, such as clockwork
Clockwork
A clockwork is the inner workings of either a mechanical clock or a device that operates in a similar fashion. Specifically, the term refers to a mechanical device utilizing a complex series of gears....
toy
Toy
A toy is any object that can be used for play. Toys are associated commonly with children and pets. Playing with toys is often thought to be an enjoyable means of training the young for life in human society. Different materials are used to make toys enjoyable and cuddly to both young and old...
s, strikers for welding
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
torches, so-called "flint-and-steel" fire-starters in emergency survival kits, and, perhaps most commonly, in butane
Butane
Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...
-type lighters, as the initial ignition source for the primary fuel. What is commonly called "flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...
" in modern times is actually ferrocerium. Also known as Auermetall after its inventor Baron Carl Auer von Welsbach
Carl Auer von Welsbach
Carl Auer Freiherr von Welsbach was an Austrian scientist and inventor who had a talent for not only discovering advances, but turning them into commercially successful products...
, it is sold under such trade name
Trade name
A trade name, also known as a trading name or a business name, is the name which a business trades under for commercial purposes, although its registered, legal name, used for contracts and other formal situations, may be another....
s as Blastmatch, Fire Steel, and Metal-Match.
While ferrocerium-and-steels function in a similar way to actual flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...
-and-steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
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
Brittle
A material is brittle if, when subjected to stress, it breaks without significant deformation . Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a snapping sound. Brittle materials include most ceramics and glasses ...
:
- Oxide - most contemporary flints are hardened with 20% iron oxideIron oxideIron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...
and 2% magnesium oxideMagnesium oxideMagnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
. - Intermetallic - in the Baron von Welsbach's original alloyAlloyAn alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
, 30% ironIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
(ferrum) was added to purified ceriumCeriumCerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...
, hence the name "ferro-cerium". Iron reacts with rare earth metals to form hard intermetallic compounds similar to those in neodymium magnetNeodymium magnetA neodymium magnet , the most widely-used type of rare-earth magnet, is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. Developed in 1982 by General Motors and Sumitomo Special Metals, neodymium magnets are the strongest...
s; such magnets are also known to generate sparks quite easily when broken.
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
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
of rare earth
Rare earth element
As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...
metals called mischmetal
Mischmetal
Mischmetal is an alloy of rare earth elements in various naturally occurring proportions. It is also called cerium mischmetal, rare earth mischmetal or misch metal. A typical composition includes approximately 50% cerium and 25% lanthanum, with small amounts of neodymium and praseodymium...
(containing approximately 50% cerium
Cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...
, 25% lanthanum
Lanthanum
Lanthanum is a chemical element with the symbol La and atomic number 57.Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is the first element of the lanthanide series. It is found in some rare-earth minerals, usually in combination with cerium and...
, and small amounts of neodymium
Neodymium
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite...
and praseodymium
Praseodymium
Praseodymium is a chemical element that has the symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is too reactive to be found in native form, and when artificially prepared, it slowly develops a green oxide coating.The element...
), plus iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and a small amount of magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
:
Iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
: 19%
Cerium
Cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...
: 38%
Lanthanum
Lanthanum
Lanthanum is a chemical element with the symbol La and atomic number 57.Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is the first element of the lanthanide series. It is found in some rare-earth minerals, usually in combination with cerium and...
: 22%
Neodymium
Neodymium
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite...
: 4%
Praseodymium
Praseodymium
Praseodymium is a chemical element that has the symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is too reactive to be found in native form, and when artificially prepared, it slowly develops a green oxide coating.The element...
: 4%
Magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
: 4%