Stir Magnet – Rare Earth Magnets For Lab Instruments & Equipment

Have you ever thought that rare earth magnets could be used on stirring tools in laboratory applications? Just follow below article to learn stir magnet!

What is magnetic stirrer?

Stirrer is an essential instruments/equipment/device for chemistry and biology experiments in scientific laboratory. And magnetic stirrer is one of important stirrer for liquid mixing.

Magnetic mixer employs a rotating magnetic field to cause a magnetic stir bar immersed in a liquid to spin very quickly, thus stirring it. It is mainly used for stirring or heat stirring low viscosity liquids or low viscosity solid-liquid mixture.

stir magnet

The magnetic stirrer consist of magnetic stir plate and magnetic stir bar. The stir plate is to provide the rotating field by permanent magnet or a set of stationary electromagnets. And then this rotating external magnetic field will spin the magnetic stir element placed in the container.

What stir magnet can be used on magnetic stir rod?

The magnetic stir rod is made with permanent magnets encased in material that won’t react with the fluid it is immersed in, such as Parylene, PTFE (a.k.a. Teflon). The stirring magnets are available in permanent Alnico magnets, ceramic magnets, rare earth neodymium magnets and samarium cobalt magnets.

Ceramic magnets are cheap and common, but not nearly as strong as a neodymium magnet.  They have only about 8-10% of the pull force.

Alnico magnets are stronger than ceramic magnets, about 25% of the strength of a neodymium magnet of the same size. They have been commonly used for stir bars, especially for high temperature use. With very low coercivity, alnico magnets are easiest to demagnetize. If exposed to a strong magnetic field, they can become weaker.

Neodymium magnets are rare earth magnet with much stronger than ferrite and alnico magnets. They are the strongest magnetic material in the world and have the highest coercivity of all permanent magnet types. These makes them ideal for mixing very viscous liquids or slurries. Although the max working temperature is lower than alnico or smco magnet, there are many choice from 60℃ to 200℃. Such as NdFeB  magnets in N42SH heat resistant to 150℃, N50 heat resistant to 80℃, N52 heat resistant to 60℃.

Samarium cobalt magnets are also a rare earth magnet with strong magnetic field. It is weaker than neodymium magnet, but Sm2Co17 magnet has higher working temperature up to 300℃. Smco magnets are also used on large magnetic agitator mixing systems in chemistry industry.

ndfeb Magnetic tumble stir discs

Many conventional stir bar companies use ceramic or Alnico magnets to make magnetic stir bars. But high-quality rare-earth magnets used in the stirrer design can ensure a strong magnetic coupling with consistent accurate alignment which significantly reduces the chance of spin-outs.

Professional Stir Magnet Manufacturer – China Magnets Source

High-quality rare-earth magnets are used in the stirrer design to ensure a strong magnetic coupling with consistent accurate alignment which significantly reduces the chance of spin-outs.

China Magnets Source Material Limited is a professional permanent magnet manufacturer and can provide all types of permanent magnet for laboratory equipment, magnetic stirrer and  magnetic stir bars/rods/elements. Whether you need magnetized or unmagnetized Neodymium Iron Boron magnets in discs, rectangular or cylinder shaped or Samarium Cobalt magnetic discs, we are the right magnet source for you.

If you are looking for an exceptional rare earth magnet manufacturer that will listen to you and deliver what you expect, email us, we are ready to serve you.

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