Is Iron Magnetic? 13 Facts You Should Know!

Iron is a soft metal used to make tools, bridges, cooking utensils, and alloys with other metals. In this article, we shall discuss the magnetic behavior of iron.

Iron is magnetic in its pure form because of the availability of four unpaired electrons, and all four electrons are aligned in the same direction and spin. It is ferromagnetic and denser matter. The iron found is hematite and magnetite rocks. The raw iron easily attracts the magnet.

The iron hardness is increased by adding a small proportion of carbon elements. Also, different metals are alloyed with iron; thus, we can find the variable magnetic responses of different iron components. We shall discuss the various magnetic properties of iron and the magnetic behavior of several irons.

Is all iron magnetic?

Based on the alloy of iron and the temperature condition, the magnetic characteristics of iron may vary. Let us list here below the different types of iron and their behavior.

Type of IronMagnetic (Yes/No)
Wrought IronYes
White cast ironYes
Grey cast ironYes
Malleable cast ironYes
Nodular cast ironYes
Pig/Crude IronNo
Iron types and their magnetic behaviour

Not all irons are magnetic because the magnetic behavior of iron varies with temperature and the number of alloy metals. It is ferromagnetic below 770 degree Celsius, and above this temperature, it is paramagnetic. If the diamagnetic metals are alloyed with iron, it affects iron’s ferromagnetic behavior.

Iron Magnetic Permeability

The magnetic permeability of iron determines the total magnetic field lines penetration through its matter. Let us talk about the magnetic permeability of iron in detail.

The magnetic permeability of pure iron is found to be 6.3 × 10-3, and its relative permeability is 5000; thus, it has a good magnetic field. The magnetic permeability of every iron matter is calculated as the ratio of the magnetic field intensity developed inside the material and the magnetizing field.

Iron Magnetic Susceptibility

The magnetic susceptibility of iron directly depends upon the magnetic field intensity. Let us discuss the magnetic susceptibility of iron in detail.

The iron magnetic susceptibility ranges from 0.62 – 1.15 × 10-3 m3/kg. The different iron matter has a different magnetic susceptibility value and is measured as the ratio of magnetization and the magnetic field intensity. It determines the degree of iron magnetization in the external magnetic field.

Iron Magnetic Field

The iron magnetic field is a vector quantity describing the force and the dipole alignment in the iron matter. Let us ponder on the magnetic field produced by the iron.

The magnetic field of annealing iron is 1 T when the external magnetic field of 0.2 × 10-3 T is applied to the matter. It is generated due to aligning magnetic dipole parallel to each other. The magnetic field produced by the iron is much stronger than the one produced by winding coils around the matter.

How does iron generate a magnetic field?

The matter produces the magnetic field mainly due to the unpaired electron. Let us now illuminate the fact behind a magnetic field generation due to the unpaired electrons.

The iron generates a magnetic field due to the magnetic dipole being aligned in a unique direction, and each dipole is aligned parallel. The unpaired electron spins and aligns them in the magnetic field direction. The intrinsic magnetic moment helps in generating the magnetic field.

Iron Magnetic Moment

The magnetic moment is a torque experienced by the particle. Let us discuss the magnetic moment of iron and its responsibility for generating the magnetic field in iron matter.

The magnetic moment of pure iron is 2.22 B.M. It is a torque felt on the unpaired electrons of iron due to the magnetic flux intensity incident on the electron that is free to move. The magnetic force tends to spin the unpaired electrons and aligns them in the external field direction.

How to calculate the magnetic moment of iron?

The total magnetic moment of iron relies upon the total number of unpaired electrons available. Let us learn how to calculate the magnetic moment of iron.

The magnetic moment of iron is calculated by using the formula m = – gJ mB sqrt(J(J+1)), where m is the magnetic moment, gJ is the g-factor, J is the quantum number which is the combination of spin and orbital quantum numbers, and mB is the Bohr magneton equal to 9.3 × 10-24 J/T and measured in mB.

Iron Magnetic Properties

The several magnetic properties of iron make it produce the strongest magnetic field. Let us list out a few magnetic properties of iron.

  • Fe is ferromagnetic below Curie point and paramagnetic above this temperature.
  • Fe is malleable and ductile, melting at 1538-28000 C.
  • Fe has permanent magnetic dipoles and retains its magnetic property throughout.
  • The intensity of magnetization of Fe is very large and positive.

Is soft iron magnetic?

Soft iron has negligible carbon and is very soft. It is used to make solenoid cores and electronic apparatus. Let us discuss whether a soft iron is magnetic or not.

Soft iron is magnetic in the presence of the external magnetic field and demagnetized quickly as soon as the magnetic field is removed. The magnetic domains are easy to move in the soft iron; hence, it does not retain the magnetism. Soft iron has low retentivity and coercivity.

Is bog iron magnetic?

Bog iron is an impure iron oxide found in swampy areas. It contains iron oxy-hydroxides and goethite. Let us see whether a bog iron is magnetic or not.

Bog iron is weakly magnetic due to the concentration of oxidized iron. It is mainly composed of goethite, which has a small concentration of iron. The iron is extracted from bog ore by a process called smelting. It is formed near groundwater consisting of iron with dissolved oxygen having low-ph.

Is molten iron magnetic?

The molten form of iron is obtained at a temperature of 1538 degrees Celsius, converting the solid iron into molten. Let us discuss whether the molten iron is magnetic or not.

The molten iron is not magnetic because, in the molten form of iron, the unpaired electrons do not align in the direction of the magnetic field and do not respond to the magnetic field. The heat energy does not allow the magnetic dipole to orient parallel in the field direction.

Is ductile iron magnetic?

Ductile iron is a form of cast iron with high tension and is rich in graphite. Let us talk about the magnetic behavior of ductile iron.

The ductile iron is magnetic due to the presence of micro-structured graphite particles. Also, these graphite particles are spherical, which allows high magnetic permeability through the ductile iron and improves its magnetization.

Is wrought iron magnetic?

Wrought iron is a mixture of iron with fibrous slag with the addition of 0.08% carbon content. Let us see whether wrought iron is magnetic or not.

The wrought iron is magnetic due to the iron concentration and fewer carbon molecules in the matter. It is soft and malleable, having good elasticity and tensile strength; hence it is good for welding and has excellent corrosion resistance.

Is cast iron magnetic?

Cast iron is an alloy with more than 2% a mixture of carbon and is produced in a Cupola furnace. Let us discuss whether cast iron is magnetic or not.

Cast iron is magnetic due to the presence of ferromagnetic iron. The magnetic properties of cast iron do not change after heating in the furnace at a high temperature. It has a low thermal coefficient expansion and good magnetic permeability, allowing the magnetic flux through the cast iron matter.

iron 2
Iron Image by Ra’ike (CC BY-SA 3.0) from Wikipedia

Is soft iron more magnetic than steel?

Steel is an iron alloy with the addition of carbon to improve its hardness and strength. Let us analyze whether soft iron is more magnetic than steel.

Soft iron is more magnetic than steel because soft iron has high retentivity than steel. Steel resists the magnetic flux through it and has high coercivity to reduce the field intensity in the applied magnetic field and demagnetize itself, while soft iron has high magnetization in the magnetic field.

Is iron magnetically hard or soft?

The magnetic field produced by the iron depends upon the intensity of the field and magnetization. Let us elaborate on whether iron is magnetically hard or soft.

The iron is magnetically soft because it can be easily magnetized in a magnetic field and demagnetized by restricting the magnetic field applied to the iron matter. The iron is also demagnetized even by the flow of direct current to it.

Why is soft iron used as magnetic keeper?

The bar or plate of soft iron is placed across the poles of the magnets. Let us understand the reason behind it.

Soft iron is used as a magnetic keeper to preserve the magnet’s strength because it is ferromagnetic and easily attracts the magnet. Using a soft iron magnetic keeper completes the magnetic circuit retaining the magnetic properties of a magnet. If it is left freely, then it will lose its magnetism.

Conclusion

We can conclude from this article that iron is magnetic, and shows ferromagnetic characteristics. Its magnetic behaviour is due to the unpaired electron that aligns parallel in the direction of the magnetic field. The magnetism of iron depends upon the temperature and the metal alloyed with it.

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