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Do Magnets Stick to Aluminum?

Overview of Magnets

A magnet is any material that can generate a magnetic field. The magnetic field is the most notable characteristic of the magnet, yet it is invisible to human sight. The magnetic field generated from a magnet can act on other magnets and ferromagnetic materials such as steel, iron, nickel, and cobalt, among others.

The oldest notes describing magnets and their properties date back about 2,500 years ago in ancient Anatolia, India, and China. In the earliest days magnets, they occurred naturally and were known as lodestones. They were described as rocks that have an affinity for iron. In recent years, however, all commercially available magnets have been manufactured by one process.

There are many types of magnets on the market, but the most efficient ones are permanent magnets. These are magnets made from rare-earth metals in a controlled industrial process. After they become magnetized, they will begin to generate persistent magnetic fields. The neodymium magnet (NdFeb) is the most popular and versatile among permanent magnets. While other permanent magnets are strong, neo magnets are particularly more affordable and durable. Hence, they have found applications across numerous industries, including health, space, automotive, manufacturing, telecommunications, and more.

Overview of Aluminum

According to scientists, aluminum is the 12th most common element in the universe. It is soft, lightweight, and very malleable. Visually, aluminum shares some characteristics with silver in its appearance and ability to reflect light. It has an affinity toward oxygen and is about three times lighter than steel. Naturally, aluminum is not ferromagnetic, meaning it can neither be attracted nor repelled by a magnet.

Aluminum was discovered in 1825, and the discovery was announced by the Danish physicist Hans Christian Ørsted. He was the same man who discovered that electric currents create magnetic fields, leading to the subsequent invention of electromagnets. Although discovered in 1825, the industrial production of aluminum did not start until 1856. Since then, it has found application across many industries, such as aviation, construction, transportation, engineering, and several others. As of 1954, aluminum became the most produced non-magnetic metal.

Do Magnets Stick to Aluminum?

Aluminum is a nonferrous metal, meaning that it cannot be magnetized and cannot the attracted by magnets. So magnets cannot stick to aluminum, no matter how long they are placed together or rubbed against one another. It has been tested numerous times, and magnets have been found to not attach to aluminum.

Can Aluminum be Magnetised?

No, aluminum cannot be magnetized because aluminum is not a ferromagnetic or ferrous material. Yes, it is a type of metal, but unlike iron, steel, and some other ferrous metals, aluminum cannot be magnetized. Magnetizing a material must have what is known as magnetic moments. When that material is exposed to an external magnetic force, they align in the same direction and form a magnetic domain. These domains will generate magnetic fields because they are all ordered in the same direction. Aluminum does not have this; Hence, even if it is exposed to a strong external magnetic field, it will not become magnetic.

How to Stick Magnets to Aluminum Trucks.

As mentioned earlier, aluminum is used extensively in transportation and manufacturing. Hence, finding vehicles or parts made with aluminum is not strange.

It is possible to stick a magnet to an aluminum truck but not by magnetism. To attach a magnet to an aluminum truck, follow these steps:

  1. Purchase an adhesive, preferably a two-part epoxy.
  2. Mix the resin and the hardener and apply the mix to one surface of the magnet.
  3. Fix the magnet on the aluminum truck.
  4. Hold it in place using tape.
  5. Wait till it is dry before peeling off the tape.

That is how to stick magnets to aluminum trucks.

What Metals Do Magnets Stick to Best?

There are several different types of magnets, most of which are ferromagnetic. When they are placed close to a magnet, they will be pulled in by the magnetic field and stuck to it. However, metals do not stick to magnets in the same way. Some metals stick to magnets better than others.

The metals that stick best to magnets are

  • Iron.
  • Nickel.
  • Cobalt.
  • Gadolinium.
  • Dysprosium.
  • Ferrous alloys such as steel.

What Kinds of Metal Do Not Stick to Magnets?

You may already have been aware that magnets do not attract or stick to materials like wood, sand, glass, rubber, plastic, and fabric but stick to metals. However, just as magnets stick firmly to some metals, some metals do not stick to magnets because they lack the properties required for magnetism. These materials include:

  1. Aluminum.
  2. Brass.
  3. Copper.
  4. Gold.
  5. Lead.
  6. Silver.

Nonferrous alloys such as aluminum bronzes.

Can Magnets Affect Aluminum in Any Way?

The question of whether magnets affect the behavior of aluminum has been considered several times, and it has also been tested to arrive at a definite conclusion. After exposing aluminum to different magnetic fields, it has been established that strong magnetic fields can affect aluminum. Although aluminum cannot attach to magnets, strong magnetic fields can move light aluminum back and forth if it is in a shape that allows movement.

For instance, if a block of aluminum is placed in a strong magnetic field, it will not be moved in any way, nor will it stick to the magnet that generates the field. However, if you pick an empty can of coke or any cylinder-shaped product made of aluminum, place it lying on a flat surface and move a piece of strong magnet back and forth over it, the field generated from the magnet will cause the can also to move back and forth.

This discovery has led to the conclusion that aluminum is susceptible to magnetism. Although aluminum may not attach to magnets, the field generated from magnets can act on it, unlike wood, glass, plastic, and other materials that are not affected by magnetism.

Which Magnetic Field Can Penetrate Aluminum?

Since it has been established that magnetic fields can act on aluminum even though they can’t attach to magnets, one wonders what strength a magnetic field can penetrate a piece of aluminum. Well, how much magnetic field is required to move aluminum is not particularly established since there are other factors at work. However, the field from a powerful permanent magnet should be able to move a can made of aluminum.

Neodymium magnets maintain their status as the most powerful permanent magnets available on the market. This is for no reason other than their properties which grant them particular abilities.

Neo magnets are made from neodymium, one of the highly ferromagnetic materials known as rare-earth metals. Although these materials are called rare-earth metals, they are not rare. They exist in large quantities, and millions of tons are used for production yearly. China has the largest deposit of rare-earth metals and holds about 90% of the world’s rare earth metals as of 2019.

Neodymium is combined with iron, boron, and other materials to form a NdFeB alloy. This alloy will then be ground and used to manufacture neo magnets through a process known as sintering. Although there are other methods to manufacture neo magnets, sintering is the most popular and one of the most efficient methods.

The properties that make neodymium magnets efficient are:

  1. The Maximum Energy Product: the max energy product, also called BHmax, refers to the magnetic flux density of a magnet. The magnetic flux density measures the strength of the field a magnet can generate. A magnet with a high max energy product will generate a strong magnetic field. Generally, neodymium magnets have high magnetic flux density, allowing them to generate strong magnetic fields.
  2. Coercive Force: the coercive Force is the resistance of a magnet against demagnetization forces—mainly external opposing magnetic fields. Demagnetizing a magnet includes exposing it to an external opposing magnetic field or heat, hitting it with a hammer, or smashing it around. The coercive Force helps the magnet to keep its domains aligned, so they don’t lose magnetism.
  3. Temperature Resistance: the temperature resistance of neodymium magnets can be classed as part of their coercivity, but it is not. Neodymium magnets can withstand high temperatures where most magnets would have already stopped functioning. This is why they are used in electric motors, starter motors, and other heat-generating components.

How to Make Aluminum Magnetic

The only way to make aluminum magnetic is to combine it with a ferrous metal such as iron or neodymium to form an alloy where the aluminum is about 60%. The alloy of aluminum and iron is called ferroaluminum, while that of aluminum and neodymium is called aluminum-neodymium. Mixing either of these metals with aluminum will produce a magnetic alloy with the physical appearance of aluminum while possessing the magnetic abilities of ferrous metals.

Conclusion

By nature, aluminum is not magnetic. Hence, it cannot attach to magnets. However, manufacturers can mix aluminum with a ferromagnetic material like neodymium to form an alloy that will be strong enough to perform in its application and can stick to magnets. If such an alloy is magnetized, it will become a magnet and generate persistent magnetic fields.

If you are looking for a professional and competent manufacturer to help you produce magnetic aluminum alloys, ROBO Magnetic is your best bet. ROBO Magnetic is a leading manufacturer in the magnets industry, manufacturing and supplying neo magnets to Europe, Asia, and North America for over 16 years. We have professional and competent engineers who use innovative technology in our manufacturing process to ensure we deliver the best. Contact us with your requirements to get started. We promise you the best experience.

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Article by

ROBO Magnetic Product Team

We are the manufacturer with 16 years of experience in custom neodymium magnets.

Need A Quote? Get in touch with us directly.

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