An Introduction to Alnico Magnets
THE ORIGINAL ONLINE MAGNET COMPANY
Alnico Magnets Information
Alnico is an alloy containing Aluminium (Al), Nickel (Ni), Cobalt (Co) hence its name Alnico. But Alnico actually contains more than just these three elements. It also contains Iron and Copper with some versions also containing Titanium and even Niobium (the Titanium versions were sometimes called Ticonal, derived from the elements TiCoNiAl). Alnico magnets were developed in the 1930’s and were the first “Real” performance permanent magnets (the first “magnets”, called magnetic steels, were quickly replaced by the vastly superior Alnico).
Alnico is produced by either a sintering method or, more commonly, a casting method. The as cast or as sintered shape is acceptable for many applications but surfaces may need to be ground for a smoother surface finish. The as cast look has darkened edges with a slightly rough texture (due to the sand mold edges); a machined face of an Alnico magnet has a bright silvery metallic surface and is usually extremely smooth as it is often precision ground.
There are 29 grades of Alnico (17 cast grades, 10 sintered grades, 2 bonded grades). Alnico has many trade names used for naming the grades such as Columax, Alcomax 3SC, Alni, Hycomax, Ticonal, etc. China has given them names starting with the letters LNG followed by a number to try to give some clarity but this is not widely utilised. Most people still know Alnico under its more common grade names such as Alnico 5, Alnico 8, Alnico 9, Alnico 5DG, Alnico5-7, Alnico8HC, Alnico 6, Alnico 2, Alnico3, Alnico 500, Alnico 400, Alnico 600 and Alnico 700, etc.
Most Alnico magnet grades are anisotropic (they can only be magnetised in a single axis / direction – they are the more powerful magnet grades of Alnico. The others are isotropic (they can be magnetised in any direction or directions) – they are weaker but offer more design and performance flexibility.
The most commonly used Alnico is Alnico 5. But care should be used when using this terminology. There are 4 version of cast Alnico 5 plus a single version of sintered Alnico 5 (it should be noted that sintered Alnico and cast Alnico have slightly different magnetic and mechanical properties). Therefore a request for Alnico 5 could result in different performing magnets due to accidental interpretation of the grade requirement.
To assist with clearly defining which type of magnet is which and how it is made, we have introduced a nomenclature which is unambiguous.
We use commonly used UK / Europe / USA namings followed by a longer unambiguous name in brackets afterwards. An example would be Alnico 5 (Alnico5_ACA44). This is an Alnico 5 version where ACA means Anisotropic Cast Alnico and 44 is the typical BHmax energy product value in kJ/m^3.
We use ACA for Anisotropic Cast Alnico, ASA for Anisotropic Sintered Alnico, ICA for Isotropic Cast Alnico, ISA for Isotropic Sintered Alnico, BA for Bonded Alnico and ACAT for Anisotropic Cast Alnico with Titanium content.
The complete range of grades is as follows:
- Alnico 5 (Alnico5_ACA34), Alnico 5 (Alnico5_ACA37), Alnico 5 (Alnico5_ACA40)
- Alnico 5 (Alnico5_ACA44), Alnico 5 (Alnico5_ASA34)
- Alnico 6 (Alnico6_ACA28), Alnico 6 (Alnico6_ASA28)
- Alnico 5DG (Alnico5DG_ACA52)
- Alnico 5-7 (Alnico5-7_ACA60)
- Alnico 8 (Alnico8_ACA38), Alnico 8 (Alnico8_ACA40), Alnico 8 (Alnico8_ACA44)
- Alnico 8 (Alnico8_ASA38), Alnico 8 (Alnico8_ASA44), Alnico 8 (Alnico8_ASA48)
- Alnico 8 (Alnico8_ICA18), Alnico 8 (Alnico8_ISA18), Alnico 8 (Alnico8_ISA20)
- Alnico 8HC (Alnico8HC_ACA36)
- Alnico 9 (Alnico9_ACAT60), Alnico 9 (Alnico9_ACAT72), Alnico 9 (Alnico9_ACAT80)
- Alnico 8HC (Alnico8HC_ASA36)
- Alnico 3 (Alnico3_ICA10), Alnico 3 (Alnico3_ISA10)
- Alnico 2 (Alnico2_ICA12), Alnico 2 (Alnico2_ISA12)
We generally offer Alnico on a customer by customer basis (bespoke magnets) but we do stock a range of Alnico magnets and will add to this range as and when necessary. We can make Alnico with modified magnetic properties upon request (by altering the manufacturing process to tune the performance of the magnet). We can also cross reference competitor data sheets and test the customer’s existing magnets to allow a direct replacement to be produced.
We supply globally to all industries, including Automotive, Aerospace, Military, Advertising, Design House, Electronic and Academic/R&D. To aid protection of information, we can also provide our services under Confidentiality Agreements / Non Disclosure Agreements / NDA. PPAP (Production Part Approval Process) is available under our NDA.
If you require a bespoke Alnico magnet or magnetic assembly, Technical Support or our Alnico Technical Data Sheet, please contact us.
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