Are not all magnets very strong? What makes magnets " […]
Are not all magnets very strong? What makes magnets "strong"? We revealed this ancient secret on our blog today.
All magnets have a specific energy density that can be measured. Not surprisingly, some of them are stronger than others. Bring the refrigerator magnets you use every day. These magnets can easily hold small strips of paper or postcards, but they cannot hold a complete newspaper or cardboard box. Heavier objects require magnets with stronger magnetic field strength.
This is also true when buying magnets for specific jobs. If you want the magnet to be strong enough to withstand heavier loads, you need a stronger magnet.
Magnets are made of various materials, the most common being ferrite (ceramic), Al-Ni-Co, Samarium Cobalt, and Neodymium Iron Boron, also known as NIB.
Why is energy density important?
Knowing the energy density of a specific magnet type allows engineers and your everyday hobbyist or school science department to understand which type of magnet is needed for the job/project they wish to work on. Although one of these magnets is called a "strong" magnet, this in no way means that the other magnets are weak. All magnets have a certain strength, depending on their energy density, but there is only one really "strong" magnet, and this one is neodymium iron boron or NIB magnets. The actual term "strong" magnet refers to this rare earth magnet called NIB magnet, which is actually the strongest magnet on earth.
These NIB magnets are called "rare earth magnets" because they are made of a rare earth alloy of neodymium, iron, and boron.
Energy density of a specific magnet
If we look at the energy density of magnets on the market today, we will see a huge difference from strong magnets such as ferrite to "strong" magnets such as neodymium iron boron. BHmax is a term used to describe the overall strength of a magnet. The BHmax of each magnet type is listed below.
Ceramic or ferrite: BHmax is 3.5
Alnico: BHmax is 5.5
Samarium Cobalt: BHmax is 26
NdFeB: BHmax is 40
From the above list, we can clearly see that although the strength of ceramic magnets is very high, there is a significant difference in BHmax or energy density compared with NdFeB magnets. This is why NIB is called a "strong" magnet. Whenever you hear someone use the term "strong" magnets, you now know that they are most likely referring to rare earth magnets called NIB magnets.
Is there any reason why people do not use NIB magnets?
These "strong" magnets are very powerful. When you use them, you must always be careful. In many cases, their high energy density is not necessary. Generally, ceramic or Anilco magnets are better choices.
As can be seen from the information given above, there are various magnets on the market. They come in various sizes and different grades, but only one type of magnet is called a "powerful" magnet. Now you know what a "strong" magnet is.