Ferromagnetism is the basic mechanism by which certain materials form permanent magnets, or are attracted to magnets. In physics, several different types of magnetism are distinguished. Ferromagnetism is the only type that can produce forces strong enough to be felt, and is responsible for the common phenomena of magnetism encountered in everyday life. One example is refrigerator magnets.
Mu-metal is a nickel-iron alloy that has very high magnetic permeability. The high permeability makes mu-metal very effective at screening static or low-frequency magnetic fields, which cannot be attenuated by other methods. The name came from the Greek letter mu which represents permeability. Mu-metal can have relative permeabilities of 80,000-100,000 compared to several thousand for ordinary steel. In addition it has low coercivity and magnetostriction resulting in low hysteresis loss.
A neodymium magnet (also known as NdFeB, NIB, or Neo magnet), a 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. This material is currently the strongest type of permanent magnet.
Cunife is an alloy of copper (Cu), nickel (Ni), iron (Fe), and in some cases cobalt (Co). The alloy has the same linear coefficient of expansion as certain types of glass, and thus makes an ideal material for the lead out wires in light bulbs and thermionic valves. It is magnetic and can be used for making magnets. Fernico exhibits a similar property. Cunife 1 consists of 60% Cu, 20% Ni, and 20% Fe. Cunife 2 consists of 60% Cu, 20% Ni, 2.5% Co, and 17.5% Fe.
Fernico is an alloy of Iron (Fer), Nickel (Ni) and Cobalt (Co). The abbreviation forms the name which is (or was) a trademark. The alloy has the same linear coefficient of expansion as certain types of glass, and thus makes an ideal material for the lead out wires in light bulbs and thermionic valves. Cunife exhibits a similar property.
Alnico is an acronym referring to metal alloys which are composed primarily of aluminium (symbol Al), nickel (symbol Ni) and cobalt (symbol Co), hence al-ni-co, and iron, with the addition of copper, and sometimes titanium. Alnico alloys are ferromagnetic, and used to make permanent magnets. Before the development of rare earth magnets in the 1970s, they were the strongest type of magnet. Other trade names for alloys in this family are: Alni, Alcomax, Hycomax, Columax, and Ticonal.
Permalloy is the term for a nickel iron magnetic alloy. Generically, it refers to an alloy with about 20% iron and 80% nickel content. Permalloy has a high magnetic permeability, low coercivity, near zero magnetostriction, and significant anisotropic magnetoresistance. The low magnetostriction is critical for industrial applications, where variable stresses in thin films would otherwise cause a ruinously large variation in magnetic properties.
Bismanol is an alloy of Bismuth, Manganese and Iron developed by the US Naval Ordnance Laboratory. It was used to make permanent magnets for use in small electric motors. Bismanol magnets have been replaced by Neodymium magnets which are both cheaper and superior in other ways, Samarium-Cobalt magnets in more critical applications, and Alnico magnets.
MKM steel, an alloy containing nickel and aluminum, was developed in 1931 by the Japanese metallurgist Tokuhichi Mishima. While conducting research into the properties of nickel, Mishima discovered that a strongly magnetic steel could be created by adding aluminum to non-magnetic nickel steel. MKM steel is tough and durable, inexpensive to produce, maintains strong magnetism when miniaturized and can produce a stable magnetic force in spite of temperature changes or vibration.
A Heusler alloy is a ferromagnetic metal alloy based on a Heusler phase. Heusler phases are intermetallics with particular composition and face-centered cubic crystal structure. They are ferromagnetic—even though the constituting elements are not—as a result of the double-exchange mechanism between neighboring magnetic ions. The latter are usually manganese ions, which sit at the body centers of the cubic structure and carry most of the magnetic moment of the alloy.
Sendust is a magnetic metal powder that was invented at Tohoku Imperial University in Sendai, Japan, about 1936 as an alternative to permalloy in inductor applications for telephone networks. Sendust composition is typically 85% iron, 9% silicon and 6% aluminum. The powder is sintered into cores to manufacture inductors. Sendust cores have high magnetic permeability, low loss, and good temperature stability.
Supermalloy is an alloy composed of Ni (79%), Mo (5%), and Fe. It is a magnetically soft material. The resistivity of the alloy is 0.6 Ω·mm/m. It has an extremely high magnetic permeability and a low coercivity. Supermalloy is used in manufacturing of components of radio engineering, telephony, and telemechanics instruments.
There are many magnetic alloys. There three magnetic substances that you will find on the Periodic Table of elements. These are iron (Fe), nickel (Ni), and cobalt (Co). Iron is the most highly magnetic material. Magnetic alloys are alloys consisting two or more of these metals. Most magnetic alloys are made to make extra powerful magnets. Steel and alnico are two of the most important alloys. Alnico is made up of iron, nickel, cobalt, and aluminum. Steel is made up of iron and carbon.