Samarium Cobalt magnets (also known as SmCo magnets) are another type of permanent magnet. A big advantage of SmCo magnets is that they can operate at temperatures up to 300 degrees Centigrade. SmCo magnets are widely used in applications in which high operating temperature and high corrosion and oxidation resistance are crucial.

These samarium cobalt magnetic discs are made of an alloy of samarium and cobalt. Their strength is similar to neodymium magnets. But what really makes samarium cobalt magnets one of the best options for use in appliances is their ability to retain their magnetic strength. For example, samarium cobalt disc magnets can function in applications that run on extreme high or low high temperatures.

Samarium Cobalt magnets (SmCo) is the sister Rare Earth Magnet to NdFeB. SmCo is sometimes called a Rare Earth Cobalt magnet. SmCo magnets exist in two alloy varieties.
Sm1Co5 (SmCo1:5) is the original SmCo alloy.
Sm2Co17 (SmCo2:17) is the more common used and stronger SmCo alloy with SmCo26 being the most popular variety.
Sm1Co5 contains mainly Sm and Co and contains no iron (Fe) so it has excellent corrosion resistance -it should never corrode with water.

Sm2Co17 is mainly Sm and Co but also contains Cu, Hf &/or Zr, sometimes Pr, and Fe. The low free iron content in Sm2Co17 means it is technically prone to a little surface corrosion when in water.

Sm2Co17 is regarded as having good to very good corrosion resistance (far superior to NdFeB) in most applications. A simple coating of NiCuNi will very likely solve any risk of corrosion.

Samarium Cobalt magnets (SmCo) may be weaker than NdFeB magnets at room temperature but SmCo will often outperform NdFeB above +150 to +180 deg C (subject to the application and grade). SmCo magnets are ideal for aerospace, automotive, sensor, loudspeaker, motor and military applications.
In mission critical applications they are an ideal first choice.
SmCo magnets offer minimal change in magnetic output over a small temperature change (with far less variation than NdFeB or ferrite; only Alnico is better).

The Low Temperature Coefficient (LTC) versions have less variation in magnetic output with temperature change (due to added Gd and Er).
SmCo magnets performance over a massive range of temperatures (from near to -273 deg C up to +350 deg C).
The H versions Sm2Co17 have higher Hci and operate up to +350°C rather than +300°C.
SmCo and NdFeB could be interchangeable e.g.
SmCo30 should perform very similarly to N30 at ambient temperature.

We can custom manufacture these to fit your exact specifications using our in-house manufacturing facilities and experienced team of engineers. Just let us know what you are looking for sending us a request for quote or contact us today, and we’ll work with you to determine the most economical solution for your project.

MaterialGradeResidual Induction (Br)Coercive Force
Intrinsic Coercive Force
Max Energy Product (BH)maxTemp. Coefficient
Max Working Temp.Curie Temp.
TkGskA/mkOekA/mkOekJ/m3MGOe%/˚C (Br)%/˚C
RECo5-200.90-0.949.0-9.4676- 7258.5-9.11194-183015-23150-16719-21-0.05-0.30250750
RECo5-220.92-0.969.2-9.6710- 7488.9-9.41194-183015-23160-17520-22-0.05-0.30250750
RE2Co17-28H1.03-1.0810.3-10.8756- 8129.5-10.2≥1990≥25207-22026-28-0.035-0.20350800
RE2Co17-281.03-1.0810.3-10.8756- 8129.5-10.2≥1433≥18207-22026-28-0.035-0.20300800
RE2Co17-321.10-1.1311.0-11.3812- 85110.2-10.7≥1433≥18230-25529-32-0.035-0.20300800
RE2Co17-28M1.03-1.0810.3-10.8676- 7968.5-10.0955-143312-18207-22026-28-0.035-0.20300800
RE2Co17-24L0.95-1.029.5-10.2541-  7166.8-9.0636-9558-12175-19122-24-0.025-0.20250800
RE2Co17-26L1.02-1.0510.2-10.5541- 7486.8-9.4636-9558-12191-20724-26-0.035-0.20250800
RE2Co17-28L1.03-1.0810.3-10.8541- 7646.8-9.6636-9558-12207-22026-28-0.035-0.20250800
RE2Co17-30L1.08-1.1010.8-11.0541- 7966.8-10.0636-9558-12220-24028-30-0.035-0.20250800
RE2Co17-32L1.10-1.1311.0-11.3541- 8126.8-10.2636-9558-12230-25529-32-0.035-0.20250800

*The above-mentioned data of magnetic properties and physical properties are given at room temperature.

*The max working temperature of SmCo magnet is changeable due to length-diameter ratio, coating thickness and another environment factors.

Features & Characteristics of Samarium Cobalt Magnets

What are the main characteristics of samarium cobalt magnets? Samarium Cobalt Magnets exhibit excellent corrosion resistance, and do not need to be protected for corrosion. SmCo magnets also offer high-resistance to demagnetization.

What are the best temperatures to use for samarium cobalt magnets? SmCo magnets are very temperature stable – their properties stay within a very narrow range up to about 300° C (570° F).

What are some common applications used for samarium cobalt magnets? SmCo’s magnetic characteristics are ideal in applications for the marine, automotive, aerospace, medical, military and industrial automation industries where high- temperature performance is critical. They are commonly used in motors, machinery, pumps, medical devices, magnetic couplings, magnetic separators and more.

What grades & shapes are available for SmCo magnets? SmCo magnets are available in a number of different grades that span a wide range of properties and application requirements. We currently stock SmCo disc magnets in grades 18 and 26, available in a wide range of sizes. If you are looking for a different shape, size or grade that what is shown on the site, just let us know by sending us a special request or contact us today.

What are recommended bonding applications for SmCo magnets? SmCo magnets are often assembled into products using “superglues” such as Loctite 325. It’s best to avoid placing mechanical stress on this material, and always ensure that bonding surfaces are clean and dry prior to bonding.

What are some safety precautions that should be taken into consideration when working with samarium cobalt magnets? SmCo magnets are hard, very brittle, and high in magnetic strength. They can snap together with great force, so please ensure that all personnel handling these magnets are aware to handle them carefully to avoid injuries. They can also chip or break if dropped or snapped together, so please take special care when handling these powerful magnets!

What is a permanent magnet? Permanent magnets represent the majority of magnetic materials available today. A permanent magnet is made from ferromagnetic materials, which have magnetic fields that do not turn on and off like electromagnets. We carry a large inventory of permanent magnets; neodymium, alnico, ceramic (ferrite) and samarium cobalt, in a wide range of shapes, sizes and grades.

What is a rare-earth magnet? Rare-earth magnets are the strongest type of permanent magnets available today. Rare earth magnets product significantly stronger magnetic fields than ceramic (ferrite) or alnico magnets. The two types of rare-earth magnets are neodymium and samarium cobalt magnets, both of which are available for on-line purchase.

How are magnets rated? Magnets are typically rated by their residual induction, coercive force & maximum energy product. This refers to the maximum strength that the magnetic material can be magnetized.

Fully dense Samarium Cobalt rare earth magnets are usually manufactured by a powdered metallurgical process. Micro size Samarium Cobalt powder is produced and then compacted in a rigid steel mold. The steel molds produce shapes similar to the final product, but the mechanical properties of the alloy usually inhibit complex features at this stage of the manufacturing process.

The various elements that compose a samarium cobalt magnet – samarium, cobalt, copper, zinc, and iron.

The Samarium Cobalt’s magnetic performance is optimized by applying a magnetic field during the pressing operation. This applied field imparts a preferred direction of magnetization, or orientation, to the Samarium Cobalt magnet alloy. The alignment of particles results in an anisotropic alloy and vastly improves the residual induction (Br) and other magnetic characteristics of the finished magnet.

After pressing, the Samarium Cobalt magnets are sintered and heat treated until they reach their fully dense condition. The rare earth magnet alloy is then machined to the final dimensional requirements and cleaned.

Physical Characteristics
Partial Physical Property Of Sintering SmCo Magnets
Parameter NameUnitSmCo 1:5SmCo 2:17
Curie TemperatureK10001100
Vickers hardnessMPa450-500550-600
Compressing StrengthMPa1000800
Electronic ResistivityΩ.Cm5-6&Times;10-58-9&Times;10-5
Bending StrengthMPa150-180130-150
Stretching StrengthMPa400350
Hot Coefficient Of Expansion(10-6/℃)‖6⊥12‖6⊥11
Note: The Above Specific Numbers Help To Consult, Not to Be The Judging Basis

Samarium Cobalt Magnet Design Pitfalls

During the design phase, it is important to consider the complexities associated with designing with magnetic materials. Not only is the magnetic performance of the magnet important, but also how your Samarium Cobalt Magnet is integrated into the final solution.

Samarium Cobalt magnetic materials, unlike common commercial materials that have ASTM classifications, are difficult to manufacture and fabricate and present a special set of challenges. Therefore, the design team must take special care when creating a custom solution for your application. Common design challenges with SmCo Magnetic Materials include:

Are typically environmentally unstable (highly reactive and prone to oxidation). Common coating and plating solutions usually do not translate to magnetic alloy.
Will gain or lose magnetic field relative to the operational temperature fluctuations necessitating the need to design for magnetic performance through a temperature spectrum.
Can experience irreparable harm at extreme temperature exposures. This harm is irrecoverable and represents an effective partial or total demagnetization of the magnet.
Challenging to fabricate because conventional machine tools and machining methods are not feasible.
Challenging to design because the magnetic field density and resulting force are not linear relative to distance.
Magnetic fields can create hazards for personal and some electronic equipment.
Common methods of component integration and retention such as; tapped holes, shoulders, through holes, staking, and tapers are expensive to employ. The integration of a magnet into a sub-assembly requires a functional knowledge base when designing an integration scheme.
Are MAGNETIZED. This seems obvious, but magnetized magnets and sub-assemblies present a unique set handling and integration problems. The issue can range from protecting the operators to demagnetizing of the magnet itself. This aspect must be accounted for early in the design phase.
Commonly requested specifications associated with aluminum, steel alloys, plastic, etc., are usually challenging to implement with Samarium Cobalt Magnets and Samarium Cobalt Magnetic Materials. These specifications, usually indicated on a drawing by default, may add cost and complexity when manufacturing a magnet or magnetic assembly. It is important to review the relevance of these industry standard features and specifications when designing and specifying a magnet or magnetic assembly.

Optimization for Performance, Cost, and Price Volatility

Oftentimes the Samarium Cobalt Alloy is the most costly part of an assembly and optimizing the magnet volume used yields financial savings. By optimizing a Samarium Cobalt Magnet design for an application using simulation software, LEC Magnetics can achieve significant cost reductions. Relative to common commercial materials such as steel, aluminum, and plastic resins, the volume of Magnet Alloy manufactured in the world is quite low. Because of the low magnetic alloy production levels and small number of mines, refinery operations, and mills, price volatility is quite common. Using an engineering oriented approach to design, LEC Magnetics can optimize your Samarium Cobalt Magnet for your application, reducing your exposure to price volatility.

Samarium Cobalt magnets are very brittle and very strong magnetically. Therefore, it is crucial to handle these magnets with extreme care to avoid personal injury and damage to the magnets. Fingers can be severely pinched between attracting magnets. Magnets can chip if allowed to “jump at” an attracting object. It is highly recommended that when constructing rare earth magnetic assemblies, they be magnetized after assembly.

Samarium Cobalt Magnets appropriate handling and packing is required. Most receiving departments are not familiar with the strength of Samarium Cobalt magnets and this can result in injury or broken parts. All personnel that may come in contact with this alloy should be made aware of the dangers of handling these magnets. The brittle nature of the alloy can lead to flying chips if the magnets are allowed to impact each other or a solid surface. Larger magnets can become a pinching hazard if caution is not exercised. We urge all customers to discuss handling techniques pertinent to their magnets.

Samarium Cobalt Magnets should be stored in a low humidity and mild temperature environment. The magnetized Samarium Cobalt alloy is very strong and it will attract ferrous particles from the air and surrounding surfaces. These particles will accumulate and appear as small “hairs” on the surface of the magnet or packaging. To combat the accumulated debris, the magnets should be kept in closed, clean containers and left in their original LECMAG wrapping. The magnets should remain in the attracting condition with all spacers intact. Metal shelving with poor clearance may cause the magnets to jump or shift as they are accessed. Do not store any magnetic material near sensitive electronics, equipment with cathode ray tubes (CRT), or magnetic storage media. Magnets which are not of the same alloy may need to be buffered from each other because of demagnetizing effects.

LECMAG’s Sintered Samarium Cobalt Magnets (SmCo) Display

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