In
materials science, galfenol is the general term for an
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...
of
iron
Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
and
gallium. The name was first given to iron-gallium alloys by
United States Navy researchers in 1998 when they discovered that adding gallium to iron could amplify iron's
magnetostrictive effect up to tenfold. Galfenol is of interest to
sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on o ...
researchers because magnetostrictor materials are used to detect sound, and amplifying the magnetostrictive effect could lead to better sensitivity of sonar detectors.
Galfenol is also proposed for vibrational energy harvesting, actuators for precision machine tools, active anti-vibration systems, and anti-clogging devices for sifting screens and spray nozzles. Galfenol is machinable and can be produced in sheet and wire form.
In 2009, scientists from
Virginia Polytechnic Institute and State University
Virginia Tech (formally the Virginia Polytechnic Institute and State University and informally VT, or VPI) is a public land-grant research university with its main campus in Blacksburg, Virginia. It also has educational facilities in six regi ...
, and
National Institute of Standards and Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical s ...
(NIST) used
neutron
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
beams to determine the
structure of galfenol. They determined that the addition of gallium changes the lattice structure of the iron atoms from regular cubic cells to one in which the faces of some of the cells become slightly rectangular. The elongated cells tend to clump together in the alloy, forming localized clumps within the material. These clumps have been described by Peter Gehring of the NIST Center for Neutron Research as "something like raisins within a cake".
See also
*
Terfenol-D
Terfenol-D, an alloy of the formula (''x'' ≈ 0.3), is a magnetostrictive material. It was initially developed in the 1970s by the Naval Ordnance Laboratory in the United States. The technology for manufacturing the material efficiently was d ...
References
{{reflist
External links
''Development and modeling of iron-gallium alloy'', Rick A. Kellogg
''Characterization and Modeling of the Magnetomechanical Behavior of Iron-Gallium Alloys'', Jayasimha Atulasimha
''Characterization of Bending Magnetostriction in Iron-Gallium Alloys for Nanowire Sensor Applications'', Patrick Downey
''Quasi-static Characterization and Modeling of the Bending Behavior of Single Crystal GALFENOL for Magnetostrictive Sensors and Actuators'', Supratik Datta
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