Sintered Magnets

What do sintered magnets mean?

Sintered Magnets are a kind of rare earth magnets. Rare earth magnets are permanent magnets that are have been developed for industrial use where there is a need for very strong magnets. Traditional natural ferrous or iron ore magnets tend to lose their magnetic property over time.

They are also very weak in terms of magnetic activity.

Hence permanent magnets are synthesized artificially for various uses where permanent strong magnets are required. Now permanent magnets are usually made of the alloy neodymium. There are two ways that neodymium magnets can be created one is by sintered process and the other by bonding.
Magnets made by the former process are called sintered magnets.

The properties of sintered magnets:

Sintered magnets are made using powder metallurgy. This is of older usage than bonded magnet process. In this process the alloy is first grinded into a fine powder. This powdered alloy is mixed with a die and then in the presence of high temperature the powder is fused into a metal.

Extremely high temperatures are required for this process to be completed successfully. Once done the sintered magnet takes a very solid form. However it is brittle and can be easily chipped or broken.
But the magnetic power of sintered magnets is higher than bonded magnets as its energy product is higher.

Although sintered magnets usually require some kind of coating to prevent corrosion. The usual coating choice is a mixture of copper and nickel that has excellent anti-corrosive properties.

Quite a few thousand tons of sintered magnets are manufactured each year. This statistics shows the huge demand that sintered magnets have in the industry today. The two countries leading in the manufacture of sintered rare earth permanent magnets are Japan and China.

A reason for this popularity is of course the fact that the magnetic performance of these kind of magnets is much higher than that of other forms of permanent magnet.

Applications of sintered magnets:

Sintered rare earth permanent magnets are almost universally used anywhere where strong magnets are required. Since most of modern technology is concentrating on reducing size, magnets have to be smaller in size but it must be strong.

Sintered magnets perfectly fit this job description. Thus they are used in both desktop and laptop hard disks and both in loudspeakers as well as headphones. They are also used in magnetic guitar pick ups and magnetic bearings.

All kinds of cordless tools also used sintered magnets. But this kind of magnets finds its most extensive use in the automobile industry. Most kinds of motors use sintered magnets. Thus the magnet finds universal use. It is the most technologically advanced magnet in the market today.