Soft Magnetic Alloys and Their Properties

NiFe (Nickel Iron) alloys Magnetic & Chemical Properties:

Magnetic & Chemical Properties
No. Properties Measurement Unit 80% NiFe7 Mumetal7 48% NiFe8 Si Steel Fe-49%
Co-2%V
1 DC Magnetic Properties Bs Tesla 0.751 0.761 1.53 1.739 2.25(11)
Br Tesla 0.42 0.52 1.13 - 1.3
B at 100 A/m Tesla - - 1.2 - -
Hc 2 A/m 0.35 0.6 2.8 -  40 to
160(12)
µ4 4 - 550000 120000 - - -
µ max - 570000 350000 190000 - 18000
2 60Hz AC Magnetic Properties µ4z5 - 70000 50000 10400 >2500 1200
µz86 - - - 54000 - -
µ max - 95000 95000 - - 12000
Core loss W/Kg 0.015 0.015 0.4 3.910 2.3 to 3.0(13),
3.8 to 5(14)
3 Chemical Composition Ni % 78-81 78-81 47-48 Nil -
Mo % 4.5-6 4.5-6 Nil Nil -
Si % 0.05-0.4 0.05-0.4 0.1 1.6 - 2.1 -
Mn % 0-0.5 0-0.5 0.50 0.5 -
C % 0.01 0.01 0.005 0.01 -
Co % - - - - 49
V % - - - - 2
Fe % Balance Balance Balance Balance Balance

Physical Properties:

Physical Properties
No. Properties Measurement Unit 80% NiFe7 Mumetal7 48% NiFe8 Si Steel Fe-49%
Co-2%V
4 Physical Properties Density g.cm-3 8.7 8.7 8.2 7.75 8.12
specific Heat J.Kg-1.˚C-1 460 460 500 - 460
Thermal conductivity W.m-1.˚C-1 19 19 13 - 33
Mean CTE between -50 & +200˚C ˚C-1 12.10-6 12.10-6 8 x 10-6 - 9.7 x 10-6
Electrical resistivity µΩ.cm 60 60 45 - 40
Curie Point ᵒC 420 420 450 - 950
Coefficient of magnetostriction at Saturation ∆l / l - 1-3 x 10-6 1-3 x 10-6 24 x 10-6 - 70 x 10-6
Melting temperature ᵒC 1450 1450 1425 - 1480
Hardness(Cold Worked) Hv 325 325 250 - 400
UTS(Cold Worked) MPa 1050 1050 850 - 1200
0.2% PS(Cold Worked) MPa 1030 1030 820 - 1150
Elongation(Cold Worked) % 3 3 3 - 2
Hardness(Annealed) Hv 160 160 140 155 220
UTS(Annealed) MPa 650 650 500 380 480
0.2% PS(Annealed) MPa 280 280 250 250 300
Elongation(Annealed) % 35 35 40 min 30 4.5
Grain Size(Annealed) - 8 8 9 - -
Hardness(Finished Part) Hv 110 110 100 - -
UTS(Finished Part) MPa 530 530 450 - -
0.2% PS(Finished Part) MPa 160 160 200 - -
Elongation(Finished Part) % 45 45 35 - -
Grain Size(Finished Part) - 0-3 0-3 0 - -

Key:

  1. Practical saturation Bs measured for H = 800 A/m.
  2. Remanent induction Br and coercive field Hc measured from H = 80 A/m.
  3. Practical saturation Bs and Remanent induction Br measured for H = 800 A/m.
  4. Measured for H = 4 mA/cm (peak value).
  5. Sinusoidal excitation field H = 4 mA/cm (peak value).
  6. Impedance permeability for B = 0.8 T.
  7. Measurements made on 35X26X0.34 mm ring specimens after annealing in Pure
    & Dry Hydrogen for 4h at 1170°C followed by cooling at 200°C/h.
  8. Measurements made on 36X25X0.34 mm ring specimens after annealing in Pure
    & Dry Hydrogen for 4h at 1150°C.
  9. Practical saturation Bs measured for H=5000A/m.
  10. Core loss W/kg at 1.5T at 50Hz=3.90 max.
  11. Practical saturation Bs measured for H=8000A/m.
  12. Depends on annealing cycle (Optimizing magnetic or mechanical property)
  13. AT B=1.5T & 50Hz
  14. AT B=2.0T & 50Hz