Hiperco 50 and Hiperco 50A: Cobalt-iron Alloys for Magnetic Applications
Hiperco 50* and Hiperco 50A* are soft magnetic alloys of 49 wt.% cobalt. 2 wt.% vanadium and balance iron [1]. They are commonly used in electric and magnetic applications where high magnetic saturation is required.
High magnetic saturation and strength
Soft magnetic materials can be magnetised and demagnetised with a relatively low magnetic field. This makes them ideal for use in transformer cores where the electric and magnetic field is rapidly changing. It is also an important property for good electromagnets, which, likewise, need to be easily demagnetised.
The magnetic saturation of a material describes the upper limit to its magnetisation. For materials which exhibit a high magnetic saturation, a high magnetic field can be achieved in the interior of the material.
Both Hiperco 50 and Hiperco 50A exhibit the highest magnetic saturation (24 Kg or 2.4 T) of all soft-magnetic alloys. In addition, they exhibit low values of coercive force (0.9 Oe or 72 A/m for Hiperco 50 and 0.4 Oe or 32 A/m for Hiperco 50A), meaning demagnetisation can be easily achieved. In addition, both exhibit high DC maximum permeability and low AC core loss [1].
Magnetic hysteresis (BH) loop for Hiperco 50 [2].
Hiperco 50 and 50A both have greater mechanical strength than other soft magnetic alloys. This makes them ideal for applications containing parts which undergo significant mechanical stress such as electrical motors and generators. One of the main differences between the two alloys lies in their mechanical properties.
The tensile strength of Hiperco 50 at 814 MPa is greater than that of Hiperco 50A at 717 MPa. Similarly, the yield strength of Hiperco 50 at 435 MPa is greater than that of Hiperco 50A at 365 MPa. Both materials have a density of 8.12 g/cm³ (0.293 lb/in³).
The ideal material for electromagnetic applications
Hiperco 50 and 50A are utilised in applications where this combination of high magnetic saturation and mechanical strength are required simultaneously with a low material weight.
This makes them an important material in the aerospace industry where they are used for rotor and stator laminations for electric motors, specifically in the main generators, auxiliary power unit (APU) and the ram air turbine (RAT) of commercial airliners [2].
Other applications of the materials are in electromagnets for medical applications, for example for X-ray optics for radiation therapy and medical radiology, pole pieces for electromagnets, speciality transformers, high magnetic flux devices and instruments and magnetic bearings for the levitation of rotating parts.
*Hiperco 50 and Hiperco 50A Trademark Carpenter Technology Corp., Reading PA, USA.
Sources
[1] Ed Fagan Inc., "Hiperco 50 and Hiperco 50A Soft Magnetic Alloys," datasheet, Ja. 2017. [Online]. Available: https://edfagan.com/litPDF/Hiperco4-29-09F.pdf. [Accessed Oct. 2, 2018].
[2] Ed Fagan Inc., "How exactly did Hiperco 50 allow Captain Sullenberger to safely land his Airbus in the Hudson River and save the day?", Ed Fagan Inc.. [Online]. Available: https://www.edfagan.com/nasa-tech-briefs-hiperco-50-50A.php. [Accessed Oct. 2, 2018].