Neodymium Iron Boron (NdFeB) Magnet

This type of magnet is composed of rare earth magnetic material, and has a high coercive force. They have an extremely high energy product range, up to 50 MGOe. Because of this high product energy level, they can usually be manufactured to be small and compact in size. However, NdFeB magnets have low mechanical strength, tend to be brittle, and low corrosion-resistance if left uncoated. If treated with gold, iron, or nickel plating, they can be used in many applications. They are very strong magnets and are difficult to demagnetize.

This is composition of Neodymium, iron and Boron Nd2Fe14B tetragonal crystalline Structure. Depends on Manufacturing process there are two type of this magnet i.e. sintered NdFeb magnets (classical Powder metallurgy) and Bounded NdFeb magnet (Rapid Solidification).

NdFeb Magnets are manufactured with the alloy of Neodymium-boron-iron and Small amount of aluminum, Niobium, Dysprosium with the following weight percentage.

The above ingredients are taken from the earth and the following method used to make magnets.

Samarium Cobalt (SmCo) Magnet

Like NdFeB magnets, SmCo magnets are also very strong and difficult to demagnetize. They are also highly oxidation-resistant and temperature resistant, withstanding temperatures up to 300 degrees Celsius. Two different groups of SmCo magnets exist, divided based on their product energy range. The first series (Sm1Co5) has an energy product range of 15-22 MGOe. The second series (Sm2Co17) has a range that falls between 22 and 30 MGOe. However, they can be expensive and have low-mechanical strength.

Samarium cobalt magnets are very strong magnet, rare earth type, permanent magnet which are made from the samarium and cobalt. They are usually manufactured by powder metallurgical process.

1:5 Series (SmCo5) are made up with 35% of samarium and 65% of cobalt

2:17 Series (Sm2Co17) are made up with 24% Samarium, 5.5% Copper, 19% Iron, 1.5% hafnium with remaining being cobalt.

Two Methods are used to manufacture SmCo Magnet.

1. Reduction/Melt Method

2. Reduction/Diffusion Method.

The reduction/ Melt method is used for both series. In this Method, the raw material is melted in an induction furnace filled with argon gas. The Casted mixture is then cooled down with water to form ingots. The Ingots are then pulverized and the particles are further milled to reduce the particle size. The resulting powder is pressed in a die of desired shape in a magnetic field to orient the magnetic field of the particles. The Sintering process is applied at temperature of 1150 to 1200 degree Centigrade followed by solution treatment 1100 degree centigrade to 1150 degree Centigrade and then finally tempering is performed at about 710 to 910 degree centigrade then is ground and further magnetized to increase its magnetic properties. The finished product is tested, inspected and packed.