Alnico Magnets
Alnico permanent magnets are made up of alloys whose major constituents are iron, aluminum, nickel and cobalt, though other elements (e.g., copper and titanium) may be included in minor amounts. Grades of Alnico vary in cobalt content, which ranges from zero (Alnico 3) to 40% (Alnico 8). The Strength of Alnico Magnets. Alnico has a high magnetic strength and a low resistance to being demagnetized and re-magnetized. Before the development of rare earth magnets, alnico magnets were the strongest type of magnet available. Today, alnico magnets have been largely replaced by stronger rare earth magnets, such as neodymium.
Alnico Resources
(Magnetic and Physical Characteristics)
The range of Alnico magnet alloy grades available from Dura Magnetics typically extends from 1.5 – 5.25 MGOe for sintered Alnico and 5.0 – 9.0 for cast Alnico. This range allows for optimizing the cost, performance, and operational temperature resistance for a wide range of applications.
Sintered Alncio magnets are made with a powdered metal process. Lower grades are isotropic, which can be magnetized in any direction, but at a loss of magnetic strength. The powder metal version of Alnico allows for easier integration of features since a tool is used and the magnet is finished to near net shape. (Sometimes the tooling cost can be a project inhibitor for small production quantities.)
Cast Alnico magnets are cast in sand molds and usually require finish grinding. Casting Alnico is the most typical manufacturing method and most cast Alncio is “orientated” and anisotropic. This means that the magnet can only be magnetized in one direction, but this improves the magnetic strength.
| Sintered Alnico - Available Grades | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Dura Magnet Grade | Residual Induction Br | Coercive Force Hc | Intrinsic Coercive Force Hci | Maximum Energy Product (BH)max | Max. Operating Temp.* | |||||
| Nominal | Nominal | Minimum | Nominal | Nominal | ||||||
| k-Gauss | Tesla | Oersted | kA/m | Oersted | kA/m | MGOe | kJ/m3 | °C | °F | |
| Alnico 2 | 7.0 | 0.7 | 500 | 40 | 540 | 43 | 1.5 | 12 | 450°C | 840°F |
| Alnico 5 | 11.0 | 1.1 | 600 | 48 | 600 | 48 | 4.25 | 34 | 450°C | 840°F |
| Alnico 8 | 8.8 | 0.88 | 1,530 | 121 | 1.600 | 127 | 5.25 | 42 | 450°C | 840°F |
| * The listed maximum operating temperatures are based on an adequate Length to Diameter ratio or a properly designed magnetic circuit. The listed values are for reference and validation must occur before one chooses a design path. Please consult a Dura technical representative before selecting or designing with Alnico magnet alloy. | ||||||||||
Alnico Magnets For Guitar Pickups
| Cast Alnico - Available Grades | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Dura Magnet Grade | Residual Induction Br | Coercive Force Hc | Intrinsic Coercive Force Hci | Maximum Energy Product (BH)max | Max. Operating Temp.* | |||||
| Nominal | Nominal | Minimum | Nominal | Nominal | ||||||
| k-Gauss | Tesla | k-Oersted | kA/m | k-Oersted | kA/m | MGOe | kJ/m3 | °C | °F | |
| Alnico 5 | 12.2 | 1.22 | 600 | 48 | 630 | 50 | 5.0 | 40 | 500°C | 930°F |
| Alnico 5B | 12.2 | 1.22 | 650 | 52 | 660 | 53 | 5.5 | 44 | 500°C | 930°F |
| Alnico 5 DG | 12.5 | 1.25 | 690 | 55 | 700 | 56 | 6.5 | 52 | 500°C | 930°F |
| Alnico 5-7 | 13.0 | 1.3 | 700 | 56 | 740 | 59 | 7.5 | 60 | 525°C | 980°F |
| Alnico 8-HC | 7.0 | 0.7 | 1,750 | 139 | 1,750 | 139 | 4.5 | 36 | 525°C | 980°F |
| Alnico 8 | 8.2 | 0.82 | 1,500 | 119 | 1,600 | 127 | 5.0 | 40 | 525°C | 980°F |
| Alnico 8B | 8.8 | 0.88 | 1,500 | 119 | 1,650 | 131 | 5.5 | 44 | 525°C | 980°F |
| Alnico 8C | 9.0 | 0.9 | 1,380 | 110 | 1,440 | 115 | 7.5 | 60 | 525°C | 980°F |
| Alnico 9 | 10.5 | 1.05 | 1,410 | 112 | 1,440 | 139 | 9.0 | 72 | 525°C | 980°F |
| * The listed maximum operating temperatures are based on an adequate Length to Diameter ratio or a properly designed magnetic circuit. The listed values are for reference and validation must occur before one chooses a design path. Please consult a Dura technical representative before selecting or designing with Alnico magnet alloy. | ||||||||||
| Reversible Temperature Coefficient for Cast and Sintered Alnico | ||
|---|---|---|
| Temperature Range (°C) | Induction Br (α) (%)/°C | Intrinsic Coercivity Hci (β) (%)/°C |
| 20°C to 150°C | -0.02 to -0.03 | -0.02 to -0.03 |
| α = Δ Br / Δ T * 100 (Br @ 20°C) [ΔT = 20°C - 150°C] β = Δ Hci / Δ T * 100 (Hci @ 20°C) [ΔT = 20°C - 150°C] | ||
Alnico Magnets For Sale
| Alnico Magnets - Physical Properties | |||
|---|---|---|---|
| Property | Units | Value Sintered Alnico | Value Cast Alnico |
| Vickers Hardness | Hv | 440 | 440-620 |
| Density | g/cm3 | 6.8 - 7.0 | 6.9 - 7.3 |
| Curie Temp TC | °C | 810 - 860 | 740 - 860 |
| Curie Temp TF | °F | 1,400 - 1,580 | 1,460 - 1,580 |
| Specific Resistance | μΩ⋅Cm | 50- 70 | 45 - 75 |
| Bending Strength | kN/mm2 | 0.35 - 0.76 | 0.05 - 0.31 |
| Tensile Strength | kN/mm2 | 0.35- 0.45 | 0.02 - 0.15 |
| Thermal Expansion | °C-1 | +11.0 to +12.4 x10-6 | +11.0 to +13.0 x10-6 |
| The listed values are approximate and should be used as a reference. Any magnetic or physical characteristics should be substantiated before selecting a magnet material. Please engage Dura's Design / Development team members before selecting a design path. | |||
Explore Our Alnico Magnet Capabilities
- Alnico magnets are ideal for corrosive and high heat applications up to 930°F (500°C).
- Dura can help optimize performance and cost with a variety of Cast and Sintered Alnico grades, including Alnico 2, Alnico 5, Alnico 5-7, and Alnico 8.
- Commonly used for various types of sensors.
- Stock Alnico magnets also available to reduce development and production lead times.
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Available Grades of Alnico Magnets:
Dura Magnetics offers both cast and sintered Alnico Magnets in a variety of grades, including Alnico 2, Alnico 5, Alnico 5-7, and Alnico 8. Our large selection of available Alnico magnetic alloys helps achieve the best balance of cost, magnetic performance, and operational temperature resistance for your specific application.
Explore available Alnico Magnet grades available from Dura Magnetics…
Corrosion Resistance:
Alnico magnets exhibit a high degree of corrosion resistance and are typically employed in applications with no coatings or plating.
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Temperature Effects:
Alnico magnets offer the best temperature characteristics of any standard production magnet material available. Alnico magnets can be used for continuous duty applications where temperature extremes up to 930°F (500°C) can be expected.
Learn more about Alnico Magnet operating temperatures above ambient temperatures…
Magnetization Options:
The lower coercive force of Alnico makes magnetizing a simple matter in most cases. In order to optimize the performance of Alnico magnets, it is advisable to magnetize the magnet after assembly with other circuit components.
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Compliance and Intellectual Property Considerations:
Alnico magnets manufactured by Dura Magnetics are compliant with Intellectual Property Rights, Environmental Restrictions, and Conflict Mineral usage.
- DFARS Compliant
- RoHS, RoHS II, RoHS III and REACH
Handling and Storage of Alnico Magnets:
Alnico Magnets are very strong and brittle, requiring appropriate handling and packing to ensure safety and prevent damage.
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Alnico Magnet Manufacturing Methods:
Alnico Magnets are typically manufactured by a powdered metallurgical process utilizing rigid steel or rubber molds.
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