ALNICO MAGNETS

Alnico magnets are made primarily from aluminum, nickel, cobalt, copper, iron and sometimes titanium. They can be either cast or sintered. Not sure if alnico is the best material for your application? Click here for an attribute and application comparison for all of the magnetic materials we offer.

Choose from one of the following shapes:

Alnico Rod Magnets

Alnico Magnetic Assemblies

Alnico Bar Magnets

Alnico Holding Magnets

Alnico Magnetic Plugs

Alnico Horseshoe Magnets

Applications
Attributes
Tolerances
Machining
Magnetizing & Handling
Magnetic & Physical Properties
Compare & Contrast

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

CAST VS. SINTERED ALNICO MAGNETS

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.

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 Cast Alnico

Size parameters range from 1 ounce to about 70 pounds
Will cast to a variety of shapes and sizes

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 are 5 and 8

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.)

Machining

Alnico is a very hard and brittle material and does not lend itself to conventional machining. The Magnet Source™ employs experienced machinists and the proper equipment to grind alnico to its required dimensions.

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.

Typical Magnetic and Physical Properties of Alnico Magnet Material
Magnetic Material	Density		Max. Energy Product BH (max)	Residual Induction BR	Coercive Force HC	Intrinsic Coercive Force HC	Normal Maximum Operating Temp.		Curie Temp.
Magnetic Material	lbs/in	g/cm	MGO	Gauss	Oersteds	Oersteds	Fº	Cº	Fº	Cº
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

Compare and Contrast Magnetic Applications and Materials

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	Attributes of Cast Alnico Size parameters range from 1 ounce to about 70 pounds Will cast to a variety of shapes and sizes 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 are 5 and 8

Applications of Neodymium Magnets Magnetic separators Linear actuators Microphone assemblies Servo motors DC motors (automotive starters) Computer rigid disc drives, printers and speakers	Attributes of Neodymium Material Very high resistance to demagnetization High energy for size Good in ambient temperature Moderately priced Material is corrosive and should be coated for long term maximum energy output Low working temperature for heat applications, but higher levels of heat resistance materials are being introduced periodically

Applications of Ceramic Magnets Speaker magnets DC brushless motors Magnetic Resonance Imaging (MRI) Magnetos used on lawnmowers and outboard motors DC permanent magnet motors (used in cars) Separators (separate ferrous material from non-ferrous) Used in magnetic assemblies designed for lifting, holding, retrieving and separating	Attributes of Ceramic Material Least expensive material compared to alnico and rare earth magnets High intrinsic coercive force Available in simple shapes only due to manufacturing process Lower service temperature than alnico, greater than rare earth Finishing requires diamond cutting or grinding wheel Lower energy product than alnico and rare earth magnets Most common grades of ceramic are 1, 5 and 8 (1-8 possible) Grade 8 is the strongest ceramic material available Tooling can be expensive

Applications of Samarium Cobalt Magnets Computer disc drives Sensors Traveling wave tubes Linear actuators Satellite systems Motors where temporary stability is vital	Attributes of Samarium Cobalt Material High resistance to demagnetization High energy (magnetic strength is strong for its size) Good temperature stability Expensive material (cobalt is market price sensitive)

Call 1.888.293.9399 for information or click here to request a quote.

ALNICO MAGNETS

Call 1.888.293.9399 for information
or click here to request a quote.