As scrap metal buyers in Melbourne, we often recommended using a magnet to help to identify metal for sale or recycling. This process helps to determine if it is a ferrous or non-ferrous metal and narrows down the material’s components. But why are some metals magnetic and others not? What makes a material magnetic? As experts in all matters of metal recycling, the team at Metal Men Recycling is here to detail metals and magnetism.
What happens when a metal is magnetic?
Magnetism is when a force attracts or repels magnetic objects. When the electrons within an atom of a material move in a particular way, that material becomes magnetic. Spinning electrons orbit the central nucleus of atoms, and in some atoms, like the metal iron, a subatomic force makes the spin of electrons from neighbouring atoms also line up combining their magnetic fields.
This produces a magnetic field that extends outside of the atoms and causes the metal itself to be magnetic. Due to their atomic structure, some metals naturally have magnetism by default, but other metals can become magnetised or demagnetised if certain conditions are met.
3 kinds of magnetic metals
Due to their internal structure, metals can respond to magnets in three ways: ferromagnetic, paramagnetic and diamagnetic.
- Ferromagnetic metals are considered truly magnetic. These metals are strongly attracted to the magnet and that force can be seen and felt. Iron is a ferromagnetic metal.
- Paramagnetic metals are weakly attracted to magnets. However, they do not retain magnetism when the magnetic field is removed like ferromagnetic metals. Some examples of paramagnetic metals include platinum and aluminium.
- Diamagnetic metals are weakly repelled by both poles and are the materials that are generally considered “non-magnetic”. This includes gold, silver and lead.
3 kinds of magnetism
How long a piece of scrap metal remains actively magnetic can also help to differentiate the type of metal. Metal can have magnetic properties in three ways: permanently, temporarily and electromagnetically.
- Permanently magnetic materials are always producing their own magnetic field due to their atomic makeup, like ferromagnetic metals.
- Temporary magnets only display magnetic properties under the right environmental conditions. Steel is an example of a temporary magnet as it needs a strong magnetic field to become magnetic.
- Electromagnets only produce a magnetic field when an electrical current is passed through them.
Which metals are magnetic?
Many metals and their alloys are magnetic due to their internal makeup, while other metals need stronger magnetic fields or an electrical current to exhibit magnetic properties.
Some examples of magnetic metals include:
Knowing the magnetic response of the metal helps to determine which metal to use in electrical equipment and other devices. For example, copper is considered non-magnetic, so, copper wire is used in electrical wiring. However, if you introduce a large enough magnetic field, all types of metal will interact with magnets. Therefore, strong metal detectors can still register “non-magnetic” diamagnetic metals like gold and silver.
Are you looking for scrap metal buyers in Melbourne?
Metal Men Recycling is a family-owned team of scrap metal buyers in Melbourne. With our streamlined 24-hour pick-up service, we offer the best prices on the market for a variety of scrap metals. Our reliable team is ready to cater to your metal recycling needs and recycle your unwanted waste.
Whether you’re looking to sell scrap metal or would just like to learn more about the process and environmental benefits of metal recycling, give us a call on 03 5941 6677 or fill out our online contact form.