SmCo Magnets – The Ultimate Guide

SmCo stands for samarium and cobalt, which are rare earth elements renowned for making extremely strong magnets.

Samarium cobalt magnets often include additional elements such as iron and copper, which equip them with temperature stability and corrosion resistance.

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SmCo Magnet Composition

 

Developed in the early 1970’s samarium cobalt magnets are some of the most widely utilized permanent magnets. They are generally manufactured from rare earth magnetic elements and this makes them extremely effective.

The principal elements utilized in SmCo permanent magnets are samarium and cobalt. However, other elements are often incorporated to boost functionality and durability.

SmCo Magnet Composition
SmCo Magnet Composition

Samarium (Sm)

Samarium often accounts for 25-35% of samarium cobalt magnets. It is a distinct type of rare earth element responsible for equipping magnets with robust magnetic powers. It is classified under lanthanide elements and is represented by atomic number 62.

Cobalt (Co)

Cobalt is represented by atomic number 27 and it accounts for the majority of SmCo magnets’ composition at 60-70%. Its primary role in the magnet is to avert the loss of magnetism by elevating coercivity.

Additional Elements

SmCo rare earth magnets are often injected with traces of other components to improve magnetic properties.

For instance, traces of iron (Fe) can be added to enhance the magnet’s ability to withstand temperature fluctuations. Other elements that are often added include copper, which helps the magnet tolerate mechanical stress.

Advantages of SmCo Permanent Magnets

Samarium cobalt rare earth magnets continue to grow in popularity as technology advances and this is primarily thanks to their unique and diverse advantages. Here are the main advantages of these permanent magnets:

Exceptional Magnetic Strength

SmCo permanent magnets are generally regarded as some of the best permanent magnets because they exhibit great magnetic properties. They generate robust magnetic fields and this is a consequence of their magnetic energy product (BHmax). The average Bhmax value of samarium cobalt magnets ranges from 16-32 MGOe and this qualifies their use in a number of high-tech applications.

Outstanding Temperature Stability

Samarium Cobalt permanent magnets are prominently utilized in high-temperature magnetic applications and devices. This is made possible by the magnet’s exceptional ability to work efficiently and optimally even under extreme heat. This feature sees them emerge as superior alternatives compared to neodymium permanent magnets. They have a curie temperature of 700-800 °C and a topmost operating temperature of 250-550°C.

Resistance to Corrosion

Most permanent magnets necessitate coating to overcome corrosion and oxidation. However, this is not always the case with Smco rare earth magnets. These magnets exhibit a significant amount of resistance to corrosion qualifying their deployment in applications prone to moisture and volatile chemicals.

High Durability

SmCo magnets are a distinct class of permanent magnets characterized by long operational lifespans. These magnets can provide exceptional services while demonstrating high magnetic strengths over a number of decades. Additionally, they are corrosion-resistant and have high temperature stability meaning they can withstand harsh conditions.

Compact Size

Samarium cobalt rare earth magnets are often manufactured in compressed sizes and this hardly shrinks their magnetic strength. They in fact demonstrate stronger magnetic properties compared to larger magnets made from other elements. The compact size makes them ideal for devices and applications that need to prioritize space.

Limitations of Samarium Permanent Magnets

The exceptional magnetic properties exhibited by SmCo rare earth magnets mean that they are indispensable in numerous applications. However, this does not mean they are devoid of shortcomings. Here are some of the drawbacks associated with SmCo magnets.

Relatively Costly

The elements used to make SmCo permanent magnets are scarce and this translates into higher prices. Additionally, manufacturing these magnets involves sophisticated processes making them more expensive.

Compared to rival magnets like neodymium and ceramic magnets, they are quite costly. However, the extra cost is offset by the strong magnetic properties they exhibit.

Fragility

Samarium cobalt magnets are generally frail and once they are subjected to physical force, they tend to break or shatter. This fragmentation or shattering can result in the deprivation of magnetic strength.

This consequently forbids the use of SmCo magnets in devices prone to mechanical force. However, this limitation can be easily overcome by practicing the recommended care practices.

Prone to Demagnetization

SmCo permanent magnets demand proper handling to retain magnetism permanently. If certain operational conditions are contravened, the magnets lose their magnetic features.

For instance, if the magnet is subjected to great physical force or extremely hot conditions, its magnetic strength may depreciate significantly.

Types of SmCo Magnet Grades

Samarium cobalt rare earth magnets are typically manufactured in varying grades and this reflects the diversity of their applications. Although there are multiple SmCo magnet grades, there are only two that are well-known and in high demand.

Sm1Co15 Permanent Magnets

This grade of SmCo magnets consists of samarium and cobalt at a ratio of 1:5 respectively. The energy product of Sm1Co15 magnets ranges from 15-24 MGOe and this elevates their temperature stability.

They have a curie temperature of roughly 700°C and are highly unlikely to get demagnetized. For this reason, they are prominently used in aerospace applications as well as medical equipment.

Sm2Co17 Permanent Magnets

Sm2Co17 grade magnets contain samarium and cobalt at a ratio of 2:17. They have an energy product BHmax range of 22-32 MGOe meaning they can generate extremely high magnetic fields.

Their curie temperature (approximately 800°C) is also higher than that of the Sm1Co15 grade magnets. This makes them ideal for use in electric motors, audio speakers, and magnetic sensors.

SmCo Magnet Grades
SmCo Magnet Grades

Properties of Samarium Cobalt Permanent Magnets

SmCo rare earth magnets find usage in a myriad of diverse applications mainly because they possess unique and unmatchable properties.

These properties make them stand out when compared to other magnets. Here are the primary features that make samarium cobalt magnets some of the best in the industry:

SmCo Magnet Temperature Characteristics

SmCo magnets are mainly renowned for demonstrating high-temperature stability. This means they can function properly even when subjected to high heat. Additionally, they do not suffer magnetization loss.

The two grades of samarium cobalt magnets exhibit different levels of thermal stability with Sm1Co15 boasting a maximum operational temperature of 250 degrees. The Sm2Co17 grade boasts a maximum operating temperature of 350 degrees and a curie temperature of roughly 800 degrees. The curie temperature of Sm1Co5 magnets on the other side is approximately 700 degrees.

SmCo Magnets Anti-Corrosion Characteristics

In addition to showing superior thermal stability, samarium cobalt magnets also exhibit strong anti-corrosion characteristics. They rarely suffer oxidation or rusting making them perfect solutions for applications that are often subjected to moisture.

Unlike other magnetic materials such as neodymium, samarium cobalt magnets do not require additional coating to overcome corrosive elements.

However, when dealing with extremely volatile conditions, SmCo magnet manufacturers may employ surface treatment using coatings such as nickel to boast corrosion resistance.

SmCo Magnet Density

Magnet density simply measures the magnet’s mass per unit volume and is often indicated in grams per cubic centimeters (g/cm³).

Samarium cobalt permanent magnets have always demonstrated a comparatively higher energy density compared to other permanent magnets. This means that they can reserve very high magnetic energy in small volumes hence why they are relatively compact in size.

Most Sm1Co15 permanent magnets have magnetic densities ranging from 7.2-8.4 g/cm³. The majority of Sm2Co17 permanent magnets on the other hand have magnetic densities ranging from 8.2-8.4 g/cm³.

SmCo Magnet Strength

The magnetic strength of samarium cobalt magnets is often measured by the strength of the magnetic fields generated. SmCo permanent magnets demonstrate one of the highest magnetic energy products (BHmax) dwarfing the energy product of other permanent magnets like ferrite magnets.

For samarium cobalt magnets, the energy product ranges from 16 MGOe to over 32 MGOe and this is impressively high given that ceramic magnets have an energy product range of 1-5 MGOe. Neodymium permanent magnets however exhibit a more superior BHmax.

SmCo Permanent Magnets Coercivity

Coercivity describes a magnet’s resistance to demagnetization and samarium cobalt rare earth magnets have a very high coercive force.

However, multiple factors can influence the coercivity of SmCo magnets including the manufacturing process. Coercivity is typically measured in kiloampere per meter (KA/m) or kiloersted (KOe).

SmCo5 permanent magnets tend to exhibit a lower coercivity force compared to Sm2Co17 permanent magnets.

Properties of SmCo Magnet
Properties of SmCo Magnet

Types of SmCo Rare Earth Magnets

Over the years, the number of high-end technologies dependent on SmCo magnets has proliferated tremendously.

This has forced SmCo magnet manufacturers to come up with varied alternatives to gratify the ever-growing demand. Here are the main classifications of samarium cobalt magnets based on composition, size, and shape.

SmCo Ring Magnets

SmCo ring magnets are some of the most renowned SmCo magnet types. They are named after the shape they resemble.

They are circular in shape with a void that makes them look like real rings. Samarium cobalt ring magnets are easy to mount and they exhibit powerful magnetic fields. This explains why they are commonly deployed in loudspeakers and magnetic sensors.

SmCo Ring Magnets
SmCo Ring Magnets

SmCo Block Magnets

Samarium cobalt block magnets resemble a block and they can be in the shape of a square or a rectangle.

They have a flat surface and their north and south magnetic poles are located at both ends making them extremely robust. SmCo block magnets are mainly deployed in magnetic separation applications, motors, and manufacturing.

SmCo Block Magnets
SmCo Block Magnets

SmCo Bar Magnets

SmCo bar magnets are rectangular in shape and they are very popular owing to their strong magnetic fields.

They have a high aspect ratio and this makes them perfect for applications necessitating powerful magnetic fields. These applications include research and magnetic separation.

SmCo Bar Magnets
SmCo Bar Magnets

SmCo Rod Magnets

The shape of Samarium cobalt rod magnets resembles an actual rod and they are cylindrical with a regular diameter along their length.

This shape makes it easy to place them in distinct devices. SmCo rod magnets are mainly used for magnetic stirring but they can also be used in medical devices and magnetic sensors.

SmCo Rods Magnets
SmCo Rods Magnets

Samarium Cobalt Deep Pot Magnets

SmCo deep pot magnets come in different shapes and they feature a samarium cobalt magnet enclosed in a shell made of either steel or other alloys.

The enclosing shell typically features a hole, which makes it easy to install the magnets. They are primarily used for magnetic holding applications hence they are quite popular in the automotive industry.

SmCo Deep Pot Magnets
SmCo Deep Pot Magnets

Arc SmCo Magnets

Samarium cobalt arc magnets feature a curved shape which makes them look like actual arcs. They generate partial magnetic fields along the arc’s periphery and this makes them ideal for applications requiring limited magnetic forces.

For instance, Arc SmCo magnets are commonly employed in electric motors, magnetic couplings, and generators.

Arc SmCo Magnets
Arc SmCo Magnets

Countersunk Hole SmCo Ring Magnets

Countersunk hole SmCo ring magnets resemble typical ring magnets but with a countersunk hole.

This eases greatly the process of mounting these magnets since one can fix them smoothly with a screw. They are broadly utilized in magnetic door closures, signage holding, and cabinet latches.

Countersunk Hole SmCo Ring Magnets
Countersunk Hole SmCo Ring Magnets

SmCo Cylinder Magnet

Samarium cobalt cylinder magnets can be identified by their cylindrical appearance, which boosts their magnetic fields.

They are quite strong hence they are widely deployed in medical equipment, magnetic sensors, and electric motors.

SmCo Cylinder Magnets
SmCo Cylinder Magnets

SmCo Disc Magnets

Just like typical discs, SmCo permanent disc magnets are thin and they bear a flat circular surface.

They are compact and this qualifies their use in applications necessitating high precision. SmCo disc magnets are greatly revered in magnetic sensor applications as well as magnetic bearings.

SmCo Disc Magnets
SmCo Disc Magnets

SmCo Hollow Magnets

Hollow samarium cobalt magnets look like cylindrical magnets but with a void at the center. This void makes them light in weight thereby qualifying their application in weight-sensitive devices.

SmCo hollow magnets are often used in the aerospace industry as well as in medical equipment.

SmCo Hollow Magnets
SmCo Hollow Magnets

Bonded SmCo Magnets

Bonded samarium cobalt magnets have not been on the market for as long as some of the other types of SmCo magnets.

Their manufacturing process involves blending samarium cobalt powder with a polymer binder. The resulting mixture is then squeezed and molded appropriately. Bonded SmCo magnets are easily customized hence they are broadly deployed in consumer electronics.

Bonded SmCo Magnets
Bonded SmCo Magnets

SmCo Sintered Magnets

Sintered samarium cobalt magnets are perfect for devices operating within hot conditions because they are manufactured by sintering SmCo powder. The sintering process utilizes high temperatures and this strengthens the magnet’s magnetic properties.

SmCo sintered magnets offer excellent thermal stability and high corrosion resistance.

SmCo Sintered Magnets
SmCo Sintered Magnets

SmCo vs Neodymium Magnets

Samarium cobalt magnets and neodymium magnets are undoubtedly two of the most prominent and effective types of permanent rare earth magnets.

They both demonstrate impressive magnetic strengths but they also exhibit some varying degrees of distinction.

Aspect SmCo Permanent Magnets NdFeB Permanent Magnets
Composition. The principal elements are samarium and cobalt. Traces of other elements can also be added. The primary element is neodymium but with traces of iron and boron.
Magnetic Energy Product. They have a magnetic energy product ranging from 15-32 MGOe. They are extremely strong and boast of a magnetic energy product ranging from 32-52 MGOe.
Temperature Stability. They have relatively higher temperature stability at approximately 350°C. Their temperature stability is comparatively lower at approximately 80-150 °C.
Cost. They are comparatively more costly given that samarium and cobalt are hard to come. They are relatively cheaper to manufacture hence they have lower price tags.
Corrosion Resistance. Cobalt makes SmCo permanent magnets quite resistant to corrosion and oxidation. They are often affected by corrosion but this limitation is often suppressed by wrapping their surface with anti-corrosive coatings.

 

Samarium Cobalt (SmCo) Magnets Manufacturing Process

Samarium cobalt magnets are highly regarded and revered because they exhibit excellent magnetic properties.

To create high-performing SmCo magnets, a complex process is needed and caution must be exercised to guarantee the quality of the final product.

Step 1: Preparation of the Raw Materials

Before the manufacturing process commences, the raw elements are sourced and treated to ensure quality.

Different preparation processes can be employed but the most common pre-treatment processes include the addition of supplementary elements like iron and copper.

Step 2: Alloy Heating

After adequate preparation of the rare earth elements, the resulting elements are injected into a furnace and melted at extremely high temperatures. The temperature is controlled to avoid messing with the composition and capabilities of the magnetic material.

Step 3: Ingot Casting

The resulting liquid is consequently withdrawn from the furnace and cooled down into molds of distinct sizes and shapes. These molds are known as ingots, which can be resized depending on the intended use.

Step 4: Ingot Annealing

Annealing is primarily carried out to strengthen the magnetic properties of the magnetic materials. This step essentially subjects the resulting ingots to constant heat. This also polishes the microstructure of the ingots.

Step 5: Magnetization

After annealing the ingot, the sized SmCo magnetic material is exposed to stronger magnetic fields. This magnetizes the material, equipping it with robust magnetic properties. The magnetization process simply lines up the magnetic domains uniformly.

Step 6: Cutting

The fully magnetized SmCo magnetic material is then divided into smaller sizes bearing different shapes as demanded. The resulting magnets are finished products ready for shipping.

Step 7: Surface Treatment

Although samarium cobalt magnets exhibit strong anti-corrosion capabilities, they can be coated with an anti-corrosive material. This is particularly paramount for magnets meant to be deployed in highly corrosive environments.

Safety Tips when Handling Samarium Cobalt Magnets.

It is extremely important to always practice caution and safety when handling samarium cobalt magnets.

This can avert injuries and damage as well as elevate the productivity of the magnets. Here are some of the safety tips one should practice:

  • Always put on protective armor such as gloves and goggles to avert unnecessary injuries.
  • Always keep the SmCo magnets far from sensitive electronics to prevent interference and data loss.
  • Always reserve the SmCo permanent magnets as per the instructions provided. Keep them far from external magnets which can interfere with the alignment of the magnetic domains.
  • Employ magnetic shielding techniques when handling extremely robust samarium cobalt magnets.
  • Always ensure that they are inaccessible to children to avert bodily harm.
  • Always adhere to the usage instructions provided by the SmCo magnet manufacturer.

SmCo Rare Earth Magnets Uses

Among the myriad of rare earth magnets available in today’s market, SmCo rare earth permanent magnets are subject to a lot of demand. This is primarily because they are versatile and highly beneficial. Their uses transcend the following industries:

SmCo Loudspeaker Magnets

SmCo loudspeaker magnets are specially built to boast the quality of sound produced by audio speakers. They are extremely durable and can stand the test of time despite being subject to relatively high temperatures and vibrations.

SmCo Magnet for Lifters

SmCo magnets for lifters provide a more efficient and cheaper way to hold and lift heavy loads in manufacturing industries and even ports.

They possess exemplary magnetic strength, which makes them capable of lifting and transporting ferrous objects.

SmCo Magnet for Motor

Motors are often exposed to heat and this means that certain magnets with inferior thermal stability cannot be mounted on motors. SmCo magnets for motors, on the contrary, are perfect for motors given that they can tolerate high temperatures and withstand demagnetization.

SmCo Magnets for Actuators

Actuators are mandatory for certain systems and machines to run. Motion in the actuators needs magnets to initiate and samarium cobalt magnets have proven to excel in this role. The stability of their magnetic strengths guarantees stable and consistent performance of the actuators.

Samarium Cobalt Magnets for Magnetic Couplings

Magnetic couplings necessitate robust magnetic fields to disseminate torque.

SmCo rare earth magnets have the capacity to generate magnetic fields that are strong enough for the magnetic couplings. These couplings are broadly utilized in chemical processing and underwater applications.

SmCo Magnets for Magnetic Bearings

Advanced high-speed equipment is now exploiting magnetic bearings to warrant smooth operations.

However, these bearings necessitate robust magnetic forces and SmCo magnetic bearings offer exactly that. This explains the broad deployment of samarium cobalt magnets in centrifuges and flywheels among other applications.

Additional Uses of SmCo Magnets

  • Magnetic sensors
  • Drilling systems
  • Wind turbines
  • Medical gadgets.
  • Pipeline inspection
  • Magnetic stirring
  • Magnetic storage
  • Turbo machinery

Conclusion

SmCo is a permanent magnet that plays an important role in many industries. They come in many grades and shapes.

If you are looking for high grade SmCo rare earth magnets, contact us now.

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