Extra strong magnets for glass boards - why do you need them? What is a rare-earth magnet is? Here’s everything to know about rare-earth magnets.
Extra strong magnets for glass boards: all you ever wanted to know about rare-earth magnets
Extra strong magnets for glass boards: they’re extra important! If you’ve ever used one of our premium glass whiteboards, odds are you’ve tried out the extra strong magnets that these glassboards
require. Made from rare-earth elements, these magnets are even more fascinating than they are handy. Today we’re going to delve into rare-earth magnets: what they are, how they work and what makes them so cool.
What is a magnet?
First, a magnet, in simple terms, is an object that produces a magnetic field. This field is invisible, but is responsible for the force that both:
A.
Pulls on other “ferromagnetic” materials like iron
B.
Repels or attracts other magnets.
Next, magnets can either be permanent magnets or temporary magnets. The key difference is that permanent magnets retain their magnetism after exposure to a strong external magnetic field. Materials capable of becoming permanent magnets, as well as the materials those magnets attract, are called ferromagnetic materials.
And even with all the advances in physics over the past few hundred years, scientists still don’t entirely understand how magnets work.
What they do know is that large-scale magnetism, like the kind seen in bar magnets, results from magnetic fields. These fields naturally radiate from the electrically charged particles that make up atoms. The most common of these magnetic fields come from negatively charged particles called electrons.
Typically, the magnetic fields of the electrons all point in different directions and cancel each other out. It’s when these fields all align in the same direction that things get interesting. When this occurs, the material generates a net magnetic field. Magnetism!
Rare-earth magnets - which have recently become commonplace - exhibit unusually strong magnetism. So, let’s look at them.
What is a rare-earth element?
Rare-earth elements are a set of 17 chemical elements in the periodic table. Unlike the common elements everyone knows - such as gold, iron and mercury - these have unfamiliar names like dysprosium, neodymium and ytterbium.
And, while called “rare-earth” most of the elements on this list are pretty plentiful in the earth’s crust. For example, one of them, cerium, is more common than copper. Their rareness comes from the fact they’re usually never found in concentrations. Thus, mining for them is hard, hence “rare-earth”.
What is a rare-earth magnet?
Rare-earth elements are ferromagnetic, meaning they can be magnetised to become permanent magnets. However, in their pure form, the magnetism of rare-earths only appears at low temperatures. However, when rare-earth metals form certain alloys with mundane metals - like iron, cobalt and nickel - they exhibit magnetism at room temperature.
Developed in labs in the 1970s and 1980s, rare-earth magnets produce significantly stronger magnetic fields than other types of magnet. The various alloys give different magnetic strengths, but they’re all stronger than normal magnets. In fact, rare-earth magnets are the strongest permanent magnets ever made. And now they have crossed into the mainstream.
The two usual types of rare-earth magnets available are:
1.
Neodymium magnets
2.
Samarium-cobalt magnets.
Both types are extremely brittle and prone to corrosion. Because of this, they’re usually coated or plated to protect them from chipping, smashing and crumbling.
Extra strong magnets for glass boards
Invented in the 1950s, the humble whiteboard has come a long way. Today, you can buy whiteboards of every size, colour and shape. And the best of them are made from glass.
Glass whiteboards are the cream of the crop because they’re tough, durable, sustainable and a dream to use. They’re some of the only boards to come with a lifetime guarantee – a warranty that’s wholly earned.
The other great thing about glass whiteboards? They can double as notice boards. All you need is a few rare-earth magnets to take your whiteboard from brainstorming session to office pinboard at the drop of an electron.
Why do you need rare-earth magnets then?
The reason is the thickness of the glass. Ordinary fridge magnets won’t work because their magnetic field isn’t strong enough to penetrate the glass to get to the metal backing of the board. And the thickness of our boards is one of the reasons they’re so durable! So rare-earth magnets are the welcome solution.
You can do more with them than attach papers, lists and drawings to your whiteboard. A rare-earth magnet attached to a whiteboard marker or whiteboard eraser will ensure they don’t get lost. We’ve even seen people hanging hardhats, clipboards and torches on their glass whiteboards using hooks mounted to rare-earth magnets.
The science of how rare-earth magnets work
Now that you know what rare-earth magnets are and why the best whiteboards need them, let’s get into the scientific nitty gritty. First, we’re going to look at the two most common kinds of rare-earth magnets as mentioned above.
Neodymium magnets
Neodymium magnets were invented in the 1980s. They’re made up of an alloy of neodymium, iron and boron (often abbreviated to NIB).
When introduced to the market, both the raw materials and the patent licenses were very expensive. However, through the 1990s the price steadily decreased. Today, neodymium magnets are both the strongest and most affordable type of rare-earth magnet. Common applications include:
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Electric motors for cordless tools
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Hard disk drives
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Magnetic hold-downs
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Jewellery clasps
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Glass whiteboards!
Samarium-cobalt magnets
While neodymium magnets are stronger and more available, we wouldn’t have them without the samarium-cobalt magnets which were invented first. Despite their head-start, these are less common than neodymium magnets due to their higher cost and lower strength. However, samarium-cobalt magnets perform much better at high temperatures, so they tend to dominate in industrial applications.
Why are rare-earth magnets so strong?
The strength of rare-earth magnets is a combination of two factors:
1.
Their crystalline structures which have high magnetic anisotropy
2.
Their atoms can have high magnetic moments.
High magnetic anisotropy
Magnetic anisotropy is how directionally dependent a material’s magnetic properties are. When a material has a high magnetic anisotropy it means it magnetises along a specific axis, called the “easy axis”. It also means the material is resistant to magnetising in any other direction. It’s this resistance to changing direction that also gives rare-earth magnets very high resistance to losing their strength.
High magnetic moments
A magnetic moment is the orientation and strength of a magnetic object. The higher the magnetic moment, the stronger the magnet.
Rare-earth elements can have high magnetic moments because the orbital structure of their atoms contains numerous unpaired electrons. When electrons pair, they spin in opposite directions, canceling out their magnetic fields. Thus, the more unpaired electrons spinning in the same direction, the stronger the magnetic field produced.
Transform your glass whiteboard with rare-earth magnets
Rare-earth magnets are as functional as they are fascinating. Made from special alloys, they’re a great way to transform your glass whiteboard into a multi-functional noticeboard.
Now you know everything there is to know about rare-earth magnets: what they are, how they work and how they can benefit your whiteboard use.
Get in touch today! Great service, great prices and Australia-wide delivery to your door. Call us today on 1800 654 917 or send an email to info@justboards.com.au
