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Available Alnico Magnet Grades

(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.*
NominalNominalMinimumNominalNominal
k-GaussTeslaOerstedkA/mOerstedkA/mMGOekJ/m3°C°F
Alnico 27.0

0.7

500

40
540
43
1.5
12
450°C840°F
Alnico 511.0
1.1
600
48
600
48
4.25
34
450°C840°F
Alnico 88.8
0.88
1,530
121
1.600
127
5.25
42
450°C840°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.
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.*
NominalNominalMinimumNominalNominal
k-GaussTeslak-OerstedkA/mk-OerstedkA/mMGOekJ/m3°C°F
Alnico 512.2

1.22

600

48
630
50
5.0
40
500°C930°F
Alnico 5B12.21.22
650
52
660
53
5.5
44
500°C930°F
Alnico 5 DG12.5
1.25
690
55
700
56
6.5
52
500°C930°F
Alnico 5-713.01.370056740597.560525°C980°F
Alnico 8-HC 7.00.71,7501391,7501394.536525°C980°F
Alnico 88.20.821,5001191,6001275.040525°C980°F
Alnico 8B8.80.881,5001191,6501315.544525°C980°F
Alnico 8C9.00.91,3801101,4401157.560525°C980°F
Alnico 910.51.051,4101121,4401399.072525°C980°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 - Physical Properties
PropertyUnitsValue Sintered AlnicoValue Cast Alnico
Vickers HardnessHv440440-620
Densityg/cm36.8 - 7.06.9 - 7.3
Curie Temp TC°C810 - 860740 - 860
Curie Temp TF°F1,400 - 1,5801,460 - 1,580
Specific ResistanceμΩ⋅Cm50- 7045 - 75
Bending StrengthkN/mm20.35 - 0.760.05 - 0.31
Tensile StrengthkN/mm20.35- 0.450.02 - 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.

 


Did You Know?

Nickel/Epoxy/Parylene coatings can help reduce corrosion and chipping while extending magnet service life.

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