Aluminium Nickel Cobalt(AlNiCo) Alloys
Alnico Magnets Overview
AlNiCo magnets are the oldest permanent mangets, including Aluminium,Nickel、Cobalt、Ferrum and other Micro metal elements. According to different technology, AlNiCo magnet can be divided into Sintered AlNiCo and Cast AlNiCo. The shapes of AlNiCo magnet are mainly round and rectangle. Foundry technique can realize different shapes .Comparing with foundry technique, Cast AlNiCo is limited to small specifications.Among different permanent materials, Cast AlNiCo is with the lowest reversible temperature coefficient and its max. working temperature can be up to 600 Celsius degree. AlNiCo magnets are widely used in various instruments and meters and other fields.Excellent temperature stability, high residual induction, and relatively high energies characterize Alnico materials, composed primarily of alloys of Aluminum, Nickel, and Cobalt. They are manufactured through either a casting or sintering process. Cast magnets may be manufactured in complex shapes, such as horseshoes, not possible with other magnet materials. Sintered Alnicos offer slightly lower magnetic properties but better mechanical characteristics than cast Alnicos. Cast Alnico 5 is the most commonly used of all the cast Alnicos. This material is used extensively in rotating machinery, meters, instruments, sensing devices, and holding applications, to name a few.
Learn more about Alnico Magnets
Performance of Cast Alnico Magnets
| CharacterIstics Model |
Max. Energy Product | Br (Residual induction) |
Hcb (Coercive Force) |
Hcj (Intrinsic coercive Force) |
Density | Temp.Coeffienct of Br. | Curie point | Inquiry | Remark | |
|---|---|---|---|---|---|---|---|---|---|---|
| (MGOe) | (KGs) | (KOe) | (KOe) | g/cm3 | %/K | °C | Isotropic | |||
| SAlNiCo4/1 | 0.40-0.60 | 8.7-8.9 | 0.11-0.14 | 0.13-0.15 | 6.8 | -0.02 | 750 | |||
| SAlNiCo8/5 | 1.07-1.19 | 5.3-6.2 | 0.57-0.63 | 0.59-0.65 | 6.8 | -0.02 | 750 | |||
| SAlNiCo10/5 | 1.19-1.38 | 6.3-7.0 | 0.63-0.73 | 0.63-0.73 | 6.8 | -0.02 | 780 | |||
| SAlNiCo12/5 | 1.38-1.63 | 7.0-7.5 | 0.62-0.70 | 0.66-0.73) | 7.0 | -0.02 | 800 | |||
| SAlNiCo14/5 | 1.63-1.88 | 7.3-8.0 | 0.59-0.63 | 0.63-0.67 | 7.1 | -0.02 | 790 | |||
| SAlNiCo14/6 | 1.76-2.00 | 6.2-8.1 | 0.70-0.81 | 0.73-0.83 | 7.1 | -0.02 | 790 | |||
| SAlNiCo14/8 | 1.76-2.00 | 5.5-6.1 | 0.94-1.11 | 1.00-1.16 | 7.1 | -0.01 | 850 | |||
| SAlNiCo18/10 | 2.00-2.39 | 5.7-6.2 | 1.16-1.26 | 1.24-1.34 | 7.2 | -0.01 | 860 | Inquiry | ||
| SAlNiCo29/6 | 3.64-4.15 | 9.7-12 | 0.73-0.80 | 0.75-0.83 | 7.2 | -0.02 | 860 | Anisotropic | ||
| SAlNiCo30/6 | 3.77-4.27 | 10-11 | 0.73-0.80 | 0.75-0.83 | 7.2 | -0.02 | 860 | |||
| SAlNiCo42/10 | 5.27-5.77 | 9.5-11 | 1.26-1.38 | 1.30-1.43 | 7.2 | -0.01 | 860 | |||
| SAlNiCo33/11 | 4.14-4.77 | 7-8 | 1.34-1.45 | 1.39-1.50 | 7.2 | -0.01 | 860 | |||
| SANiCo35/5 | 4.40-4.90 | 11-12 | 0.60-0.65 | 0.63-0.68 | 7.2 | -0.02 | 850 | |||
| SAlNiCo37/15 | 4.65-5.15 | 7.0-8.0 | 1.76-1.85 | 1.88-1.98 | 7.2 | -0.01 | 870 | |||
| SAlNiCo39/12 | 4.90-5.40 | 8.3-9.0 | 1.45-1.54 | 1.50-1.60 | 7.25 | -0.01 | 860 | |||
| SAlNiCo44/12 | 5.53-6.03 | 9-9.5 | 1.50-1.60 | 1.56-1.66 | 7.25 | -0.01 | 860 | |||
| SAlNiCo40/15 | 5.02-6.03 | 7.5-8.5 | 1.80-1.90 | 1.95-2.05 | 7.2 | -0.01 | 870 | |||
| SAlNiCo44/15 | 5.53-6.03 | 8.0-8.8 | 1.86-2.00 | 1.95-2.05 | 7.2 | -0.01 | 870 | |||
Performance of Cast Alnico Magnets
| Characteristics Model |
Max. Energy Product | Br (Residual induction) |
Hcb (Coercive Force) |
Hcj (Intrinsic coercive Force) |
Density | Temp.Coeffienct of Br. | Curie point | Inquiry | Remarks |
|---|---|---|---|---|---|---|---|---|---|
| (MGOe) | (KGs) | (KOe) | (KOe) | g/cm³ | %/K | °c | Isotropic | ||
| AlNiCo12/6 | 1.50 | 6.4 | 0.65 | 0.70 | 7.0 | -0.03 | 810 | ||
| AlNiCo13/6 | 1.63 | 7.5 | 0.65 | 0.70 | 7.0 | -0.03 | 810 | ||
| AlNiCo18/10 | 2.26 | 5.3 | 1.13 | 1.22 | 7.1 | -0.01 | 860 | ||
| AlNiCo20/11 | 2.51 | 6.0 | 1.26 | 1.36 | 7.3 | -0.01 | 860 | ||
| AlNiCo36/6 | 4.52 | 11.5 | 0.75 | 0.78 | 7.3 | -0.02 | 850 | Anisotropic | |
| AlNiCo38/5 | 4.77 | 12.0 |
0.63 |
0.65 | 7.3 | -0.02 | 850 | ||
| AlNiCo40/5 | 5.03 | 12.5 | 0.62 | 0.63 | 7.3 | -0.02 | 850 | ||
| AlNiCo44/5 | 5.53 | 12.7 | 0.65 |
0.67 |
7.3 | -0.02 | 850 | Inquiry | |
| AlNiCo52/6 | 6.53 | 13.0 |
0.71 |
0.72 | 7.3 | -0.02 | 850 | ||
| AlNiCo60/6 | 7.54 | 13.5 | 0.74 | 0.75 | 7.3 | -0.02 | 860 | ||
| AlNiCo38/11 | 4.77 | 8.5 | 1.38 | 1.41 | 7.3 | -0.01 | 860 | ||
| AlNiCo40/17 | 5.02 | 7.5 | 1.96 | 2.11 | 7.3 | -0.01 | 870 | ||
| AlNiCo46/12 | 5.78 | 9.3 | 1.51 | 1.56 | 7.3 | -0.015 | 860 | ||
| AlNiCo48/16 | 6.03 | 8.2 | 1.81 | 1.98 | 7.3 | -0.01 | 870 | ||
| AlNiCo72/12 | 9.04 | 10.5 |
1.43 |
1.46 | 7.3 | -0.015 | 850 | ||
| AlNiCo80/12 | 10.04 | 10.8 | 1.51 | 1.53 | 7.3 | -0.015 | 850 |
Key Advantages
Sintered Alnico Magnets:
- Excellent temperature stability
- Strong corrosion resistance
- The maximum working temperature is up to 500°c
- Fine grain
- Compact crystal.
- Excellent magnetic consistence and evenness.
- Suitable for small volume and complex shape magnets.
Cast Alnico Magnets:
- Excellent temperature stability
- Strong corrosion resistance
- The maximum working temperature is up to 500°c
- Excellent capacity
- High density and magnetic properties
- Shorter production lead time
- Temperature factor of Br is the smallest among all the permanent magnets
- Cast Alnico magnets can be produced in relatively complex shapes
- Tooling for cast Alnico magnets is relatively low, since sand molds are generally used for the casting process.
Manufacturing Methods
Alnico magnets are manufactured through either casting or sintering processes.
Cast magnets are manufactured by pouring a molten metal alloy into a mold and then further processing it through various heat-treat cycles. The resulting magnet has a dark gray exterior appearance, and may have a rough surface. Machined surfaces have a shiny appearance similar to steel.
Sintered magnets are manufactured by compacting fine Alnico powder in a press, and then sintering the compacted powder into a solid magnet.
Assemblies
We are able to manufacture metal and other components of finished sub assemblies using our CNC machining facilities.
Assemblies can be fabricated by adhering magnets with adhesives to suit a range of environments, by mechanically fastening magnets, or by a combination of these methods. Due to the relatively brittle nature of these magnet materials, press fits are not recommended.
Surface Treatments
The corrosion resistance of Alnico is considered excellent , and no surface treatments are required. However, Alnico magnets are easily plated for cosmetic reasons if required.
Machining
Alnico is hard and brittle, and prone to chipping and cracking. Machining or drilling can not therefore be accomplished by ordinary methods. Holes are usually cored in at the foundry, and magnets are cast close to final size and then finish machined to closer tolerances.
Magnetizing and Handling
Alnico has a low coercive force, and is easily demagnetized if not handled with care. Because of their relatively low coercivities, special care should be taken to assure that these magnets are not subjected to adverse repelling fields, since these could partially demagnetize the magnets. Magnetized magnets should be stored with papers to reduce the possibility of partial demagnetization. If Alnicos are partially demagnetized, they may be easily remagnetized.
Temperature Effects
Up to about 1,000 F, changes in magnetization are largely reversible and re-magnetizable, while changes above this are largely structural and not fully reversible or re-magnetizable. Approximately 90% of room temperature magnetization is retained at temperatures of up to 1,000 F.