Ceramic magnets and rare earth magnets both come under the category of permanent magnets. These magnets have materials, which retain their magnetism for years, once they are given a magnetic charge. They retain their magnetic power until they are physically damaged.
Not all permanent magnets have same properties. Ceramic magnets and rare earth magnets are different from each other as they are made up of different alloys and have different resilience and strength.
In this article, we will discuss some of the main differences between ceramic magnets and rare earth magnets. Some of the points are mentioned below for your knowledge:-
- Chemical composition –
Ceramic magnets are commonly known as ferric magnets or hard ceramic magnets. They are composed of barium ferrite or strontium. Basically there are two types of rare earth magnets such as neodymium iron boron and samarium cobalt magnets. These two are called as rare earth magnets, because they are made up of lanthanide series of the periodic table of elements or rare earth.
- History –
Ceramic magnets are being used since the early 1960s. It was believed that the ceramic magnets were much stronger than the aluminum nickel cobalt magnet, which was in use before ceramic magnets. Ceramic magnets soon became popular in the market over the aluminum nickel cobalt magnets.
The samarium cobalt rare earth magnets were discovered in the 1970s and it was the first rare earth magnet to be discovered. The neodymium iron boron magnets became available in the market by the year 1984.
- Strength –
Usually the strength generated by a magnet in a magnetic field is measured with maximum energy product or the BHmax. The strength is measured in MGOe. The rule is the higher value of the BHmax defines the power of the magnet.
Ceramic magnets have 3.5 BHmax value and the samarium cobalt magnet has BHmax value of 26. Neodymium rare earth magnets are said to be the most powerful rare earth magnets, which holds a BHmax value of 40.
- Resistance power to thermal stress –
As a matter of fact, magnets tend to lose their strength when they are heated above a certain temperature. The temperature level is known as Tmax. It is recommended that any magnet should not be operated over this value. However, magnets do have a property to regain their strength back when they are cooled below the Tmax level.
Ceramic magnets hold a Tmax level of 300 degree Celsius and the rare earth magnets (samarium cobalt magnets and the neodymium magnets) hold a Tmax level of 150 degree Celsius. When a magnet is heated beyond the Tmax level, it becomes demagnetized. The temperature where it loses its magnetic field and become demagnetized is known as Tcurie.
Once the magnet reaches Tcuire, it cannot be recovered even after cooling. Ceramic magnets have a Tcurie level of 460 degree Celsius, neodymium magnets have a Tcurie level of 310 degree Celsius and the samarium cobalt magnets have a Tcurie level of 750 degree Celsius.
Ceramic and rare earth magnets have many more distinct features, which make them different from each other.