Overview: Rare Earth Magnets
We supply all types of rare earth magnets in all grades and sizes. Below is a detailed discussion of the magnets we stock. It’s important to note that we customize the magnets (on request) into any shape and size for our esteemed clients.
1. Neodymium Iron Boron
Neodymium magnets (also known as Neo magnets, NdFeB or NIB) are the most used type of rare earth magnets. Neodymium Iron Boron refers to a special type of rare earth magnet composed of a neodymium, iron and boron alloys which forms a Nd2Fe14B tetragonal crystalline structure. This structure is very strong which makes Neodymium magnets the strongest kind of rare earth magnets available today. Neodymium is readily available in sintered and bonded forms. Below are some of the main advantages and disadvantages of Neodymium magnets.
a. Higher remanence: Neodymium magnets have a higher remanence than most (if not all types of magnets) out there in the market today.
b. Higher coercivity: Neodymium magnets also have a higher coercivity (resistance to magnetization changes).
c. Higher energy product: Neodymium magnets also offer better energy efficiency hence their popularity in many highly rated energy consuming appliances/equipment.
d. Numerous applications: Neodymium Iron Boron magnets are used in a number of applications the most notable being making motors, hard disk drives, tools as well as magnetic fasteners.
e. Better magnetic properties at high temperatures: Neodymium is usually alloyed with dysprosium and terbium. This makes Neodymium magnets maintain their magnetic properties better at high temperatures (not exceeding 250C).
f. Unmatched strength: As mentioned above, Neodymium magnets are the strongest kind of rare earth magnets available today.
a. Neodymium is highly sensitive to temperature variations.
b. Neodymium also rusts and oxidizes easily. This makes it necessary to plate Neodymium before practical use. (Plating is important for preventing oxidation which is the chemical process responsible for rusting).
c. Neodymium magnets tend to have a lower Curie temperature compared to other types of magnets.
2. Samarium Cobalt (SmCo)
Samarium Cobalt is another strong type of permanent rare/scarce earth magnet. As the name suggests, the magnet is a Samarium & Cobalt alloy. Samarium Cobalt magnets date back to the early 1970’s. They are the 2nd strongest type of magnets after Neodymium magnets.
a. High temperature rating
b. High coercivity
c. Maximum energy product: Samarium Cobalt magnets have a max. Energy product i.e. BHmax which ranges from 16 to 32 MGOe (megagauss-oersteds), up to 34 MGOe which is the theoretical limit.
d. SmCo is readily available in two series namely; 1:5 and 2:17.
SmCo is brittle: Due to Samarium Cobalt’s brittleness, Samarium Cobalt magnets are prone to chipping and cracking. Other important information
The Series 1:5 Samarium Cobalt magnet alloys (popularly written as SmCo Series 1:5 or SmCo5) have 1 rare earth Samarium atom and 5 Cobalt atoms. The energy product of the Samarium Cobalt alloys ranges from 16-25 MGOe.
It’s worth noting that its easier to calibrate Series 1:5 magnets (to specific magnetic fields) than Series 2:17 magnets. Series 2:17 Samarium Cobalt magnets (usually written as SmCo Series 2:17 or Sm2Co17) are age hardened with a composition of 2 atoms of rare earth Samarium as well as 13C17 atoms of TM (transition metals).
The max. Energy product of these alloys range from 20 - 32 MGOe. 2nd generation materials can also be utilized at higher temperatures because SmCo is resistant to oxidation (with most grades working well up to 300 degrees Celsius).