Permanent Magnets

PERMANENT MAGNETS

Your source for high-quality, low-cost permanent magnets and magnetic components and assemblies for your OEM electric motor manufacturing.

A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.

But in certain materials, called ferromagnets, all the spins and the orbits of the electrons will line up, causing the materials to become magnetic. This would be your normal iron, cobalt, nickel. Permanent magnets are limited by the structure of the material. And the strongest magnetic field of a permanent magnet is about 8,000 gausses.

Types of Permanent Magnets

• Ceramic (Ferrite) Magnets
• Alnico Magnets
• Samarium Cobalt Magnets
• Neodymium Iron Boron Magnets
• Bonded – Injection Molded Magnets
• Flexible Magnets

Ceramic (Ferrite) Magnets

Ceramic, also known as Ferrite, magnets are made of a composite of iron oxide and barium or strontium carbonate. These materials are readily available and at a lower cost than other types of materials used in permanent magnets making it desirable due to the lower cost. Ceramic magnets are made using pressing and sintering. These magnets are brittle and require diamond wheels if grinding is necessary. These magnets are also made in different grades. Ceramic-1 is an isotropic grade with equal magnetic properties in all directions. Ceramic grades 5 and 8 are anisotropic grades. Anisotropic magnets are magnetized in the direction of pressing. The anisotropic method delivers the highest energy product among ceramic magnets at values up to 3.5 MGOe (Mega Gauss Oersted). Ceramic magnets have a good balance of magnetic strength, resistance to demagnetizing and economy. They are the most widely used magnets today.

Alnico Magnets

Alnico magnets are made up of a composite of aluminium, nickel and cobalt with small amounts of other elements added to enhance the properties of the magnet. Alnico magnets have good temperature stability, good resistance to demagnetization due to shock but they are easily demagnetized. Alnico magnets are produced by two typical methods, casting or sintering. Sintering offers superior mechanical characteristics, whereas casting delivers higher energy products (up to 5.5 MGOe) and allows for the design of intricate shapes. Two quite common grades of Alnico magnets are 5 and 8. These are anisotropic grades and provide for a preferred direction of magnetic orientation. Alnico magnets have been replaced in many applications by ceramic and rare earth magnets.

Samarium Cobalt

Samarium cobalt is a type of rare earth magnet material that is highly resistant to oxidation, has a higher magnetic strength and temperature resistance than Alnico or Ceramic material. Introduced to the market in the 1970’s, samarium cobalt magnets continue to be used today. Samarium cobalt magnets are divided into two main groups: Sm1Co5 and Sm2Co17 (commonly referred to as 1-5 and 2-17). The energy product range for the 1-5 series is 15 to 22 MGOe, with the 2-17 series falling between 22 and 32 MGOe. These magnets offer the best temperature characteristics of all rare earth magnets and can withstand temperatures up to 300° C. Sintered samarium cobalt magnets are brittle and prone to chipping and cracking and may fracture when exposed to thermal shock. Due to the high cost of the material samarium, samarium cobalt magnets are used for applications where high temperature and corrosion resistance is critical.

Neodymium Iron Boron

Neodymium Iron Boron (NdFeB) is another type of rare earth magnetic material. This material has similar properties as the Samarium Cobalt except that it is more easily oxidized and generally does not have the same temperature resistance. NdFeB magnets also have the highest energy products approaching 50MGOe. These materials are costly and are generally used in very selective applications due to the cost. Cost is also driven by existing intellectual property rights of the developers of this type of magnet. Their high energy products lend themselves to compact designs that result in innovative applications and lower manufacturing costs. NdFeB magnets are highly corrosive. Surface treatments have been developed that allow them to be used in most applications. These treatments include gold, nickel, zinc and tin plating and epoxy resin coating.

Injection Molded

Injection mouldable magnets are a composite of resin and magnetic powders of different materials allowing parts to be made in an injection molding process. Energy products are dependent upon the magnetic powders used in fabrication. The molding process allows for the manufacture of more complex shapes. These magnets are usually lower in magnetic strength as there are limitations to the degree of loading.

Flexible magnets

Flexible magnets are very similar to the injection molded magnets but are produced in flat strips and sheets. These magnets are lower in magnetic strength and very flexible depending on the materials that was used in the compound with the magnetic powders. Vinyl is often used in this type of magnet as the binder.

 Magnet Material Comparisons

WORKING TEMPERATURES OF MAGNETS

PERMANENT MAGNETS COMPARISON TABLE

INDUSTRIES AND APPLICATIONS OF MAGNETS

Industries

• Automotive Applications
• Home appliances
• Power tools
• Industrial motors and pumps
• EV industries
• Electric and Electronics
• Aeronautical and Marine
• Medical

Applications

• Servo Motors
• Miniature brushless DC motors
• Brushless DC motors with Hall sensors
• Brushless motors with thermistors
• Position sensors
• External rotor brushless DC motors
• Hollow shaft brushless DC motors
• Slot less brushless motors
• Ironless brushless DC motors
• DC brush type motors
• Frameless brushless DC motors
• Brush type torque motors
• Harsh environment motors
• Splined motors
• Deep well drilling motors
• Limited rotation torque motors

AUTOMOTIVE	HVAC motors Window wiper motors Window lift motors Sunroof motors Seat adjuster motors Mirror adjuster motors EPS- Electric Power steering motors Washer pump motors Fuel pump motors ABS motors APS/parking Motors Power antenna motors Starter motors Micromotors Sensors
HOME APPLIANCES	FHP motors Mixer motors Brushless DC Motors PMDC Motors Pump Motors Micromotors / DC Motors
INDUSTRIAL MOTORS	DC Motors                                                                                                                                                                   PMDC motors                                                                                                                                                                                                                                                                                                                                 Step motors                                                                                                                                                                   Servo motors                                                                                                                                                            Traction motors                                                                                                                                                                   DC generators                                                                                                                                                                        Ex-proof motors                                                                                                                                                             Tacho generators / Actuators

QUALITY

Our stringent quality management ensures product consistency covering all processes from raw material procurement to finished goods production. The products and processes pass through stringent quality tests benchmarked with global standards.

Our manufacturing facilities are ISO 9001:2015 or IATF/TS16949 certified. Our greatest asset is delivering outstanding product quality and first-class service to our customers globally.

DELIVERY

We offer warehousing locations across the UK and Europe that are set up for stocking programs and deliveries to match customer specific manufacturing and inventory requirements.

If you would like to know more about our extensive range of permanent magnet products please contact us.