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Brass is a metal that is widely preferred for its machinability, corrosion and anti-microbial properties. It finds extensive applications in many industries, including plumbing, architecture, and musical instruments. One question we get all the time is whether brass is magnetic or not. Whether you’re an engineering student or a metalworker, keep reading. In this article, you learn about the magnetic properties of brass alloy.
Is Brass Magnetic?
No, pure brass is not magnetic. A magnetic object must be able to produce a magnetic field, which repels or attracts other magnetic objects. Brass contains copper and zinc as its primary alloys. Neither of these elements is ferromagnetic, meaning they display a weak attraction to magnetic fields. Therefore, if you hold a magnet close to high-quality brass, it will not stick.
Understanding Brass Magnetism: Key Concepts
Now that you understand the magnetic properties of brass, let’s quickly uncover the different forms of magnetism.
Diamagnetism
Diamagnetic metals lack unpaired electrons. Since all electrons are paired, no net magnetic force is generated. Therefore, metals in this class are slightly repelled by magnets and lose all magnetic properties when the field is removed. Diamagnetic materials include silver, copper, gold, and most other elements on the periodic table. Brass is also a diamagnetic metal.
Paramagnetism
Paramagnetism is used to describe metals that have a small and positive susceptibility to magnetic fields. These include lithium, magnesium, and tantalum. Paramagnetic metals are slightly attracted by a magnetic field, but they lose all properties when the field is removed. Paramagnetic properties arise from the presence of some unpaired electrons and the reaction caused by the external magnetic field.
Ferromagnetism
Ferromagnetic substances exhibit a high and positive response to magnetic fields. Unlike diamagnetic or paramagnetic substances, they also retain magnetism after the external field is removed. The ferrromagnetic properties of iron, nickel, cobalt and other metals arise from the presence of magnetic domains. For more details, check the research paper on magnetism and magnetic domains.
Factors Affecting Brass Magnetic Properties
Although pure brass is a natural non-magnet, some factors can affect its magnetic behaviour. These include:
Composition
The number one aspect that determines the magnetism of brass is its composition. Despite the main elements of brass being non-magnetic, some manufacturers add steel or iron to brass, enhancing its magnetism or strength.
Processing Brass
When refining brass alloy into end products, manufacturers subject the brass to different fabrication methods such as annealing or sintering. These processes alter the position of atoms and electrons in your brass. Consequently, they may make your brass more magnetic or non-magnetic. On top of that, rapid cooling during fabrication produces a microstructure that responds fairly to magnetic fields.
Impurities in Brass
We often talk about pure metals. But it is technically impossible to have a metal that is 100% pure. The same applies to brass. Certain alloys or low-grade brass will contain impurities that are ferromagnetic in nature, making your brass magnetic.
Temperature
Another factor that influences the magnetic behaviour of your brass is the work environment temperature. The higher the temperature, the less powerful the magnetic force. In contrast, the lower the temperature, the higher the magnetic response. Having said that, you cannot skip over the environmental temperature during planning for your project. It will decide the feasibility of brass for the project.
Special Magnetic Cases of Brass
Although brass is non-magnetic by nature, there are some cases where slight magnetism is displayed. These include
Brass with Impurities or Alloying
Brass can obtain temporary magnetism when impurities such as nickel, iron, and cobalt are present. These metals are ferromagnetic; therefore, they produce a magnetic field. Impurities are less common with premium brass, but low-grade alloys might contain an excessive level of impurities.
Brass-Plated Ferrous Cores
In addition to that, you might notice that magnets might stick to brass appliances like a doorknob. How is that possible if we say straight brass is non-magnetic? The answer is simple. 99% of the time, the object is not straight brass but brass-plated steel/metal. Therefore, a magnet will stick to this object because of the magnetic steel core and not the brass coating.
Temporary Magnetism
Lastly, while brass is not magnetic, it can be temporarily magnetized. If you move a strong enough magnet over your brass, the electrons in your plate will align, creating a magnetic field. However, the field dissipates as soon as you move the magnet out of place. For more details, check the guide on induced eddy currents.
Why Brass Magnetism Matters and Its Applications
The magnetism of brass alloy matters because it influences the kind of applications brass can power. The previous section taught you special cases where non-magnetic brass might exhibit temporary magnetism. This section reveals the wide applications of brass alloy.
- Musical instruments: The non-magnetic nature of brass prevents it from interfering with the sound of musical instruments. Therefore, you can use brass to produce horns, tubas, trumpets and other instruments.
- Hospital and infrastructure: Brass is frequently used in bathroom door handles since it prevents germs from spreading. The same applies for handles of restrooms, gym, and public space doors.
- Hardware: If you work in factories or automotive, you can use brass to produce screws, hinges, bolts, and nuts.
- Plumbing: Since it is durable and easy to shape, brass is one of the best choices for plumbing components. These include connvectors, pipes, and valves, among others.
- Electrical components: You can use brass to manufacture electrical lamp holders, battery clamps, etc.
Conclusion
To sum up, brass is one of the best metals you can select for your next project. This non-magnetic metal provides excellent malleability and fair resistance to corrosion, making it suitable for countless industries. If you want premium brass CNC machining, contact HRC Metal Precision Manufacturing. We are happy to support you with any technical decisions and issues!
FAQ
● Can brass ever be magnetized permanently?
No. Since brass is mainly composed of copper and zinc, it cannot be magnetized permanently.
● Does brass stick to a magnet?
No, brass in its pure form will not stick to a magnet under normal circumstances. However, brass alloys that contain ferromagnetic elements will stick to a magnet.
● Is there a type of brass that is magnetic?
Yes, certain grades of brass exhibit higher magnetic behaviours. The reason traces back to ferromagnetic impurities or the manufacturing process.
● How can you tell if it’s real brass?
There are plenty of methods to verify if your brass is the real deal. These include visual examinations, magnetometers, sensors, eddy currents, and X-ray technologies. However, a simple test you can perform at home is the magnet test. Simply wash your brass sample, removing any impurities. Next, place it on a non-magnetic surface, then move a magnet near it. If the brass sample moves slightly, it is pure. If it exhibits a strong attraction, then it is not pure brass.
● What looks like brass but is magnetic?
Materials that are magnetic yet resemble brass are usually brass-plated steels. These objects are characterized by a steel or iron inner core and a decorative brass surface. Examples include hardware items and fittings where manufacturers want the look of brass without the higher material cost.
● Is plated brass magnetic?
A brass plate is typically not magnetic because of its chemical composition. However, if steel or iron is added in a considerable quantity, your plated brass exhibits temporary magnetism.
