permanent alnico magnet -- ALL Magnetics Inc.

 

Permanent alnico magnets

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ALNICO MAGNETS
Alnico permanent magnets are made primarily from aluminum, nickel, cobalt, copper, iron and sometimes titanium. They can be either cast or sintered.

Cast Alnico
Cast alnico is melted and poured into a mold. Once solidified, the material is rough ground and then heat-treated and cooled, sometimes in a magnetic field. When treated in the presence of a magnetic field, the magnet is called anisotropic. This orients the material to take on maximum magnetization and allows a higher gauss level. A cast magnet that is not heat-treated in a magnetic field is called isotropic. After heat treatment and cooling, the material can be ground to specific tolerances and then magnetized.

Attributes of Cast Alnico

Size parameters range from 1 ounce to about 70 pounds
Will cast to a variety of shapes and sizes
Sintered Alnico
Sintered alnico is made from a powdered mixture of ingredients that are pressed into a die under tons of pressure, sintered in a hydrogen atmosphere and then cooled either within a magnetic field or without (anisotropic vs. isotropic).

Attributes of Sintered Alnico

Size parameters range from about one ounce of material up to one cubic inch
Pressed to close tolerance/minimal grinding to finish
Mechanically strongest of alnicos
Attributes of Both Cast and Sintered Alnico

Very temperature stable, great for high heat applications
Maximum working temperature 975° - 1020° F
May be ground to size
Does not lend itself to conventional machining (hard and brittle)
High residual induction and energy product compared to ceramic material
Low coercive force compared to ceramic and rare earth materials (more subject to demagnetization)
Most common grades of alnico are 5 and 8

Alnico Bar Magnets
Alnico Bar

Alnico Bars Magnet
Alnico Channel Magnet
Alnico Horseshoes Magnet
Alnico Holding Magnet
Alnico Plugs Magnet
Alnico Rods Magnet
Ceramic Magnets
Neodymium Magnets
Samarium Cobalt Magnets
Flexible Magnets
Surplus Magnets
TYPICAL MAGNETIZATION PATTERNS


Alnico Plug Magnets
Alnico Plug
Alnico Rod Magnets
Alnico Rod
Alnico Channel Horseshoe Magnets
Alnico Channel Horseshoe
Alnico Holding Magnets
Alnico Holding Magnets
Typical Magnetic and Physical Properties of Alnico Magnet Material
Magnetic Materials
Density
Maximum
Energy
Product
BH (max)
Residual
Induction
Br
Coercive
Force
Hc
Intrinsic
Coercive
Force
Hc
Normal
Maximum
Operating
Temp.
Curie
Temp.
lbs/in
g/cm
MGO
Gauss
Oersteds
Iersteds
Alnico 5 (cast)
0.264
7.3
5.5
12800
640
640
975
525
1580
860
Alnico 8 (cast)
0.262
7.3
5.3
8200
1650
1860
1020
550
1580
860
Alnico 5 (sintered)
0.250
6.9
3.9
10900
620
630
975
525
1580
860
Alnico 8 (sintered)
0.252
7.0
4.0
7400
1500
1690
1020
550
1580
860
Applications of Alnico Magnets
Magnetos, separators, sensors, electron tubes, traveling wave tubes, radar, holding magnets, coin acceptors, clutches and bearings, motors, distributors, relays, controls, generators, receivers, telephones, microphones, bell ringers, guitar pickups, loudspeakers, security systems, cow magnets.

Tolerances
Unless otherwise specified, our tolerances on alnico material meet and often exceed International Magnetics Association (IMA, formerly MMPA) standards. For unfinished surfaces (as cast) the following tolerances apply: 0-1” ± .016 1-3” ± .031 3-5 ± .047
5-7” ± .062 7-9” ±.078 9-12” ± .094

Finished surfaces are normally ground to ± .005 (See MMPA standards for more details.)

Magnetizing and Handling
Magnetizing is done after the magnet has been machined to the correct tolerances. Care should be taken when handling alnico material since it is brittle and can chip or break if dropped on a hard surface. Also, because it has a low resistance to demagnetization, it will lose power if it is stored improperly (poles repelling each other). For best results, store magnetized alnico so that pieces are attracting each other, or with a steel keeper.
Machining
Alnico is a very hard and brittle material and does not lend itself to conventional machining. ALL Magnetics Inc. employs experienced machinists and the proper equipment to grind alnico to its required dimensions.

Copyright © ALL Magnetics Inc Tel: 714-632-1754 Address: 2831 Via Martens, Anaheim, CA 92806