Alnico magnet was developed in the early 1930’s. During World War II  it was used in military electronic applications. After the war Alnico Magnet quickly spread into civilian versions of those applications and replaced magnet steel in many applications. High induction levels with good resistance to demagnetization and stability, due to its low temperature coefficient (0.02% / °C), at a reasonable cost made Alnico magnet material of choice. A high working temperature limit (550 °C / 1020 °F) makes Alnico magnet especially well suited for sensitive automotive and aircraft sensor applications.

Alnico magnet material is made by alloying aluminum, nickel and cobalt with iron. Some grades also contain copper and/or titanium. The alloying process is casting or sintering. The process and the heat treatment needed to optimize magnetic properties produces hard (Rc45) and brittle parts that are best shaped or finished by abrasive grinding. Cast parts of Alnico magnets are generally under 70 pounds and may be used as-is, but polar surfaces are usually ground flat and parallel. Sintering is confined to high volume parts in sizes under one cubic inch and an effective press length to diameter ratio under four.

AlNiCo magnetic material is an alloy of Aluminum-Nickel-Cobalt which possesses excellent temperature stability and high residual induction. AlNiCo magnets have a low Coercive Force that limits their applications in many cases. Casting and sintering are two major processes used to manufacture the AlNiCo magnets.

AlNiCo Bar Magnets are the popular shape AlNiCo magnets. We provide AlNiCo Bar Magnets for various applications. Alnico is an acronym regarding an own family of iron alloys which in addition to iron are composed basically of aluminum (Al), nickel (Ni) and cobalt (Co), subsequently al-ni-co. additionally, they encompass copper, and on occasion of titanium. Alnico alloys are ferromagnetic, with a high coercivity (resistance to loss of magnetism) and are used to make permanent magnets. earlier than the improvement of rare-earth magnets within the Nineteen Seventies, they have been the strongest kind of everlasting magnet. other alternate names for alloys in this own family are Alni, Alcomax, Hycomax, Columax, and Ticonal. The composition of alnico alloys is typically eight–12% Al, 15–26% Ni, 5–24% Co, up to six% Cu, up to 1% Ti, and the balance is Fe. The improvement of alnico commenced in 1931, while T. Mishima in Japan discovered that an alloy of iron, nickel, and aluminum had a coercivity of four hundred oersteds (Oe; zero.07957 kA/m), double that of the first-class magnet steels of the time. We can also produce magnets to custom specifications by request.

Alnico magnets are ideal for corrosive and high heat applications up to 930°F (500°C).

Alnico magnets commonly used for various types of sensors.
The Alnico Horseshoe Magnet has two magnetic poles close together. Ideal for school experiments and it makes a great gift. Includes a keeper to help retain magnetic power.

Typical Magnetic Performance for Cast Alnico Magnet
GradeUS Standard MMPA
Equivalent
Max. Energy ProductRemanenceCoercive ForceRev. Temp.Coeff.CurieTemp.WorkingTemp.Density
(BH)maxBrHcBrHciTc TwD
MGOekJ/m3kGmTOekA/m%/°C%/°C°C°Cg/cm3
★LN9Alnico 31.139.06.868038030-0.03-0.028104506.9
★LN101.2010.06.060050040-0.03-0.028104506.9
★LNG12Alnico 21.5512.47.272050045-0.03+0.028104507.0
★LNG13Alnico 21.6012.87.070060048
 LNG37Alnico 51.6537.012.0120060048-0.02+0.028505257.3
LNG40Alnico 55.040.012.5125060048-0.02+0.028505257.3
LNG44Alnico 55.544.012.5125065052-0.02+0.028505257.3
LNG52Alnico 5DG6.552.013.0130070056-0.02+0.028505257.3
LNG60Alnico 5-77.560.013.5135074059-0.02+0.028505257.3
LNGT28Alnico 63.528.010.0100072058-0.02+0.038505257.3
LNGT36JAlnico 8H4.5036.07.07001750140-0.025+0.028605507.3
★LNGT18 Alnico 82.218.05.85801250100-0.025+0.028605507.3
LNGT32Alnico 84.032.08.08001250100-0.025+0.028605507.3
LNGT405.040.08.08001380110
LNGT60Alnico 97.560.09.09001380110-0.025+0.028605507.3
LNGT729.072.0 10.510501400112
REMARK: ★=ISOTROPIC OTHERS=ANISOTROPIC
Typical Magnetic Performance for Sintered Alnico Magnet
GradeRemanence
Br
Coercivity
Hcb
Intrinsic Coercivity
Hcj
Max. Energy
Product
(BH)max
DensityWorking
Temp
Tc
Remark
KGsTKOeKa/mKOeKa/mMGOeKj/m3g/cm3
FLN85.20.520.5400.54431.0-1.258-106.8760Isotropic
FLNG127.00.70.5400.54431.5-1.7512-147.0810
FLNGT145.70.570.95760.98781.75-2.014-167.1850
FLNGT185.60.561.1881.13902.25-2.7518-227.2850
FLNG2810.51.050.58460.59473.5-4.1528-337.2850Anisotropic
FLNG3411.01.10.63500.64514.3-4.834-387.2890
FLNGT2810.01.00.7560.71573.5-3.828-307.2850
FKNGT317.80.781.31041.13903.9-4.531-367.2890
FLNG33J6.50.651.71351.881504.15-4.533-367.2850
FLNGT388.00.81.551231.581264.75-5.338-427.2850
FLNGT428.80.881.51201.531225.3-6.042-487.25850

Features & Characteristics of Alnico Magnets

What are the main characteristics of alnico magnets? Alnico magnets offer high magnetic strength, energies but low coercivities. They are less brittle than Rare Earth magnets, are highly resistant to corrosion, have excellent temperature stability and can be used at very high temperatures. Manufactured through either a casting or sintering process, they can be made into complex shapes (such as horseshoe shapes) that are not possible with other magnet materials.

What grades & shapes are available for alnico magnets? Grades 5 and 8 are the most commonly used Alnico grades. Non-standard shapes can be custom fabricated to blueprint specifications from raw stock in sintered, or cast forms, & we can custom manufacture virtually any shape & size to meet your specialty requirements. Send us a request for quote, and we’ll work with you to determine the most economical way to manufacture your specialty project.

Are there machining constraints for alnico magnets? Alnico magnets are hard and brittle, and prone to chipping & cracking. They require very careful machining & it is not generally recommended that these materials be used for structural or decorative purposes. Machining or drilling cannot be accomplished by ordinary methods. Cutting & grinding should be done prior to magnetizing. Holes must be made by EDM methods. We are fully equipped to machine these materials to your blueprint specifications.

What are some common applications for alnico magnets? Instrumentation, meters, microwave devices, actuators, holding devices, sensors, are among the most common applications for Alnico magnets.

Do alnico magnets require surface treatments? Alnico magnets do not typically require a protective coating or plating since they exhibit excellent resistance to corrosion.

What are some safety precautions that should be taken into consideration when working with alnico magnets? Special care should be taken to assure that these magnets are not subjected to adverse repelling fields, since these could partially demagnetize the magnets. If Alnicos are partially demagnetized, they may be easily re-magnetized.

What is a permanent magnet? Permanent magnets represent the majority of magnetic materials available today. A permanent magnet is made from ferromagnetic materials, which have magnetic fields that do not turn on and off like electromagnets. We carry a large stock inventory of permanent magnets; neodymium, alnico, ceramic (ferrite) and samarium cobalt, in a wide range of sizes, shapes and grades.

Most alnico magnets are manufactured using typical foundry casting techniques, where the molten alloy is poured into sand molds. Very small magnets, usually one ounce or less, are produced using press and sinter techniques. Sintered Alnico magnets have features which make them particularly effective in very small precision devices. Sintering magnets with small holes and intricate shapes is possible. Sintered magnets are available in both isotropic and anisotropic form, with a broad range of unit properties. Their magnetic properties are similar but often slightly lower than cast magnets of equivalent grade.

Alnico magnets, cast and sintered, are finished ground using abrasive grinding to produce the final shape and tolerance. Once ground the material is a shiny metallic finish. These materials are brittle and cannot be machined or drilled.

LEC Magnetics offers a wide selection of Alnico magnet products. View on our desired product style type:

Alnico Rod Magnets
We stock Alnico rod magnets in Grade 5. We can supply grade 8 upon request. We will grind them to your specifications.

Square Bar Magnets
Alnico bar magnets offer excellent temperature stability, high residual induction, and relatively high energies.

Rotor Magnets
Our rotor magnets are made of Alnico 5 material and supplied un-magnetized (magnetization provided after assembly).

Cow Magnets
Adams supplies Alnico Cow Magnets in Alnico Grade 5. Other types are available upon request.

Channel Magnets
Alnico channel magnets can be used for holding applications and also for removal of tramp iron from chutes.

Button Magnets
Each button magnet includes a metal keeper for storage and to help retain magnetic strength.

Horseshoe Magnets
Alnico horseshoe magnets provide a compact, high power magnetic source, and are used for traction, lifting, sorting, clamping and retrieval.

Alnico magnets are very brittle and very strong magnetically. Therefore, it is crucial to handle these magnets with extreme care to avoid personal injury and damage to the magnets. Fingers can be severely pinched between attracting magnets. Magnets can chip if allowed to “jump at” an attracting object. It is highly recommended that when constructing rare earth magnetic assemblies, they be magnetized after assembly.

Alnico Magnets should be stored in a low humidity and mild temperature environment. The magnetized Alnico alloy is very strong and it will attract ferrous particle from the air and surrounding surfaces. These particles will accumulate and appear as small “hairs” on the surface of the magnet or packaging. To combat the accumulated debris, the magnets should be kept in closed, clean containers and left in their original LECMAG wrapping. The magnets should remain in the attracting condition with all spacers intact. Metal shelving with poor clearance may cause the magnets to jump or shift as they are accessed. Do not store any magnetic material near sensitive electronics, equipment with cathode ray tubes (CRT), or magnetic storage media. Magnets which are not of the same alloy may need to be buffered from each other because of demagnetizing effects.

The packaging methods of Alnico magnetized alloys are dependent upon the magnet size and the customer requirement. LEC Magnetics offers standard packaging. Please alert your LECMAG contact if you require a deviation from these methods.

LECMAG’s Sintered and Cast Alnico Magnets (AlNiCo) Display

LECMAG Magnetic Technologies supports customers around the world in applying our technical know-how to provide initial and ongoing engineering and manufacturing support.

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