Alnico Magnets                                              

ALNICO MAGNETS

An acknowledged leader in the field of permanent magnets for over 50 years, Arnold continues its tradition of superior quality and value with a full line of Alnico products.

We produce a range of Alnico magnets including standard Alnico bar, Alnico rod, Alnico c-channel parts, as well as custom parts from less than an ounce to almost 100 pounds.  We also offer Alnico die-cast in aluminum, Alnico magnets dipped in plastisol and Alnico assemblies.

Common products include Alnico horseshoe or c-shaped magnets for beam focusing such as for radar use, Alnico cylinders for seals or sensors, and chip collection magnets.  We are also proud to have produced American made Alnico for guitar pickups for over fifty-years going back to the inception of the electric guitar.

One of the oldest members of our magnet family, Alnico remains the workhorse of the permanent magnet industry and can be relied upon to deliver impressive flux density at an economical price.  Alnico also boasts the lowest temperature coefficient of any commercial magnet material (0.02% per degree centigrade) allowing for excellent stability over a wide temperature range.  It is also inherently corrosion resistant.

Alnico has experienced renewed interest in recent years for use in such temperature-sensitive applications as hall-effect and MR-based automotive and electronic sensors. This is in addition to the traditional magnetron, TWT amplifier, actuator, motor and instrument applications that have long relied upon Alnico.

Our Alnico is produced in Arnold's Marengo, Illinois factory which is ISO9001:2000 and AS9100:2004 Rev.B certified.  The product produced is  DFARS compliant and, as it is produced in the U.S., will also be in compliance with ITAR regulations.

COATINGS, Die-CASTINGS, and PAINTING

Arnold offers alnico die-cast in aluminum as well as Alnico dipped in plastisol and Mil-spec painting.

CUSTOM ASSEMBLIES

We can offer custom Alnico assemblies using your components and Arnold Magnetic Technologies magnetic materials.  We can also manufacture your assembly completely in house, making both the magnetic components and non-magnetic components and assemble these parts allowing you to receive a completed unit or sub-assembly.  We can also work with your component suppliers as well as our own to develop the most cost effective solution to your needs.

DESIGN CONSIDERATIONS

Because Alnico magnets are coarse-grained, hard, and brittle, they cannot be drilled or conventionally machined.  Given these mechanical properties, Alnico parts are not normally used as structural members.  Where a choice exists, select simple shapes.  Slots are preferred over holes. Cross sections of less than .125" (3.18 mm) should be avoided.  Finished surfaces, when required, may be produced by grinding; however, for many applications, the "as cast" or "as sintered" surface yields a satisfactory result at a significantly lower cost.  To facilitate mounting and give adequate protection to the magnet, special assemblies such as rotors and magnetron magnets may be supplied with an aluminum jacket.  Additionally, l ow carbon steel pole pieces may be attached to magnet pole faces by adhesive bonding or with studs or bolts.  Plastisol or paint can be applied for improved appearance.

MAGNETIZATION

The most efficient use of Alnico requires that it be magnetized after the magnet has been assembled with its pole pieces in the final magnetic circuit.  Shipping the product non-magnetized also eliminates the need for special packaging, and prevents contamination by stray iron-chips, etc.  Magnetic saturation at the end-use location requires the application of a magnetizing force 4 to 5 times greater than the coercive force of the material.  For Alnico 5, a magnetizing force of 3000 oersteds (240 KA/m) is recommended.  For Alnico 8, the magnetizing force should be at least 7000 oersteds (560 KA/m).  The magnetizing force need be applied only momentarily.  Thus, impulse magnetizers employing a capacitor discharge are commonly used.  Direct current magnetizers are also effective.

STABILITY AND TEMPERATURE EFFECTS

Alnico magnets offer excellent stability with respect to temperature changes: reversible change is 0.02% per degree Centigrade.  Heating may produce an irreversible loss of magnet strength.  The magnitude of loss depends upon the dimensions of the magnet and its composition, but is usually less than 5%, and may be recovered by remagnetization.  At temperatures exceeding 1000° F (538° C), a metallurgical change takes place which causes magnetic strength to reduce rapidly.  This change will not be recovered by remagnetization.

External magnetic fields can also induce partial demagnetization.  In some critical applications, it is desirable to stabilize the magnet by intentionally reducing magnetic output by 5% to 10%.  Such stabilization may reduce, or even eliminate the effect of stray external fields.

RoHS COMPLIANCE

Arnold Alnico Magnets are  RoHS compliant .