When you take a moment to think about it, a magnet really is quite a wonderful thing! This invisible force that attracts metal and can repel or attract other magnets seemingly defies the laws of physics, and many a young child has been steered towards a life in science thanks to early experiments in their schooldays involving magnetic force. There are many different types of magnets, and they are not just playthings but important items in a wide array of appliances and other uses. Let’s have a look at magnets in more detail and consider how to understand the force of a magnet.
More About Magnets
The history of magnets is one of interest, as magnets were not in fact invented, but ‘discovered’. Magnetite is a naturally occurring mineral that – as the Ancient Greeks noticed many centuries ago – had properties that attracted metal objects. It wasn’t until a scientist by the name of William Gilbert, an Englishman, began researching the subject of magnetism in the late 1500’s that the phenomenon became more widely known.
Today, magnets are used in many different areas: they are found in industry in some heavy machinery, notably in the mining industry and others where metal needs to be separated from other minerals. Magnets are also used in various medical equipment, notably the likes of MRI scanners, and also form an important part of most electric motors. As we shall see, the latter use is one reason why custom magnets bulk manufacturing is a strong and growing industry.
Back to the title, and distinguishing the force of an individual magnet involves a good understanding of the science involved, and the ability to interpret complex mathematical formulas. Without getting too deep into that, we will look at the difference between two types of common magnetic – the ceramic magnet, and the rare-earth magnet.
Ceramic vs. Rare-Earth
Until relatively recently, indeed as late as the 1950’s, magnets for all uses were made from naturally magnetised ore, such as Lodestone. These magnets did the job but were never very powerful. In the 1950’s it was discovered how to create ceramic magnets – made from barium or strontium ferrite – which could be made in various strengths. This gave magnets greater versatility.
Further developments in magnets came about with the discovery that ‘rare-earth’ elements could be made into magnets. The first, the samarium cobalt magnet or SmCo, were born in the 1970’s and represented a great stride forward in magnetic production. The breakthrough came in the mid-1980’s with the development of the neodymium magnet, or NdFeB, with its mix of neodymium, boron and iron constituents.
These days the latter are the most powerful type of magnets available to buy. The strength of magnetic field a magnet produces is measured in a scale called BHmax, arrived at by the complex calculations we mentioned earlier. To give you an idea of the different magnetic strength, look at this: the BHmax rating of a ceramic magnet is 3.5. The equivalent neodymium magnet has a rating of 40!
There’s your answer – the neodymium magnet is the one you need!
