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Samarium Cobalt (SmCo) Magnets:
For High-Temperature Applications
Discover high-performance Samarium Cobalt (SmCo) magnets. Unmatched temperature stability and corrosion resistance for aerospace, medical, and military applications. Custom grades available.
What Are Samarium Cobalt (SmCo) Magnets?
Samarium Cobalt (SmCo) magnets represent a class of high-performance rare-earth permanent magnets specifically engineered to excel in extreme operating conditions where other magnet types may fail or degrade. These magnets are an alloy primarily composed of Samarium (Sm) and Cobalt (Co). Their unique composition and manufacturing processes yield magnetic properties that are indispensable in demanding environments.
The market generally recognizes two main series or generations of Samarium Cobalt magnets: SmCo5 (the 1:5 series) and Sm2Co17 (the 2:17 series). The SmCo5 series represents the first commercially available SmCo magnets, while the Sm2Co17 series is a more advanced generation, offering superior high-temperature performance and enhanced magnetic properties. This distinction is crucial for understanding their respective capabilities and applications. SmCo magnets are positioned as the premier choice when critical factors such as high temperature or severe corrosive environments render Neodymium magnets unsuitable. This positioning highlights their specialized role as a robust solution for challenging engineering problems, often justifying a higher initial investment due to their unparalleled reliability and performance in critical applications.
The Unmatched Advantages of Samarium Cobalt
Extreme Temperature Stability
Samarium Cobalt magnets maintain their magnetic properties and operate reliably at temperatures far exceeding the limits of standard Neodymium magnets. Their typical continuous operating temperature range extends generally up to 250°C - 350°C (482°F - 662°F), with some specialized grades capable of performing effectively at even higher temperatures, up to 550°C. This exceptional thermal resilience is a cornerstone of their utility in high-heat environments.
A significant characteristic contributing to their thermal stability is their very low reversible temperature coefficient. This means that their magnetic output remains remarkably stable and predictable across a wide range of temperature fluctuations. For precision applications where consistent magnetic performance is paramount despite varying thermal conditions, this stability is a critical design factor. The ability of SmCo magnets to maintain predictable performance under thermal stress is a key differentiator, ensuring operational integrity in environments that would cause other magnet types to degrade or fail.
Superior Corrosion Resistance
SmCo magnets are inherently resistant to corrosion and oxidation due to their composition. Unlike iron-rich Neodymium magnets, which are highly susceptible to rust and require protective coatings, Samarium Cobalt magnets do not easily corrode.
This inherent resistance offers a significant practical benefit: in most applications, SmCo magnets do not require a protective coating. The absence of a coating requirement eliminates the need for additional processing steps, reduces material costs associated with coatings, and simplifies both design and assembly processes. While SmCo magnets may have a higher upfront material cost compared to Neodymium, the elimination of coating requirements translates into substantial savings in manufacturing complexity, processing time, and long-term maintenance. This contributes to a lower Total Cost of Ownership (TCO) for the end-user, especially in high-volume production or for products requiring long-term reliability in corrosive or humid environments. This consideration shifts the focus from simple unit price to a more holistic economic perspective, which is a key factor for procurement and engineering teams in high-performance industries.
Samarium Cobalt: Technical Specifications
Magnetic & Thermal Properties
Key magnetic and thermal properties for various Samarium Cobalt grades are detailed below. These fundamental values enable engineers to accurately assess a magnet's performance characteristics, including magnetic field strength, resistance to demagnetization, energy density, and temperature limits. This comprehensive data empowers you to identify the optimal balance between magnetic performance and temperature resistance for your specific application, demonstrating our commitment to providing precise information.
| Series | Grade | Remanence ($B_r$) (kG) | Coercive Force ($H_{ci}$) (kOe) | Intrinsic Coercivity ($H_{cj}$) (kOe) | Max. Energy Product ($(BH)_{max}$) (MGOe) | Max. Op. Temp. | Temp. Coeff. of Remanence ($\alpha_{Br}$) (%/°C) |
|---|---|---|---|---|---|---|---|
| (SmCo) 1:5 Series | XG16 | 7.7-8.6 | 7.2-8.4 | >20 | 15-18 | 250°C / 482°F | -0.04 |
| XG18 | 8.2-9.0 | 7.8-8.8 | >20 | 16-20 | 250°C / 482°F | -0.04 | |
| XG20 | 8.6-9.2 | 8.2-9 | >20 | 18-22 | 250°C / 482°F | -0.04 | |
| XG22 | 9.0-9.5 | 8.5-9.3 | >20 | 20-23 | 250°C / 482°F | -0.04 | |
| XG24 | 9.5-10 | 8.9-8 | >20 | 22-25 | 250°C / 482°F | -0.04 | |
| XG25 | 9.7-10.2 | 9.2-10 | >20 | 23-24 | 250°C / 482°F | -0.04 | |
| (SmCo) 2:17 Series | XGS20L | 8.6-9.2 | 4.5-8.8 | 15-18 | 18-22 | 350°C / 662°F | -0.035 |
| XGS20 | 8.6-9.2 | 7.8-8.8 | 18-25 | 18-22 | 350°C / 662°F | -0.035 | |
| XGS20H | 8.6-9.2 | 7.8-8.8 | >25 | 18-22 | 350°C / 662°F | -0.035 | |
| XGS22L | 9.0-9.5 | 4.5-9.2 | 15-18 | 20-24 | 350°C / 662°F | -0.035 | |
| XGS22 | 9.0-9.5 | 8.2-9.2 | 18-25 | 20-24 | 350°C / 662°F | -0.035 | |
| XGS22H | 9.0-9.5 | 8.2-9.2 | >25 | 20-24 | 350°C / 662°F | -0.035 | |
| XGS24L | 9.5-10 | 4.5-9.7 | 15-18 | 22-26 | 350°C / 662°F | -0.035 | |
| XGS24 | 9.5-10 | 8.6-9.7 | 18-25 | 22-26 | 350°C / 662°F | -0.035 | |
| XGS24H | 9.5-10 | 8.6-9.7 | >25 | 22-26 | 350°C / 662°F | -0.035 | |
| XGS26L | 10-10.4 | 4.5-10 | 15-18 | 24-27 | 350°C / 662°F | -0.035 | |
| XGS26 | 10-10.4 | 9.0-10.0 | 18-25 | 24-27 | 350°C / 662°F | -0.035 | |
| XGS26H | 10-10.4 | 9.0-10.1 | >25 | 24-27 | 350°C / 662°F | -0.035 | |
| XGS28L | 10.4-10.8 | 4.5-10.5 | 15-18 | 26-28 | 350°C / 662°F | -0.035 | |
| XGS28 | 10.4-10.8 | 9.5-10.5 | 18-25 | 26-28 | 350°C / 662°F | -0.035 | |
| XGS28H | 10.4-10.8 | 9.5-10.5 | >25 | 26-28 | 350°C / 662°F | -0.035 | |
| XGS30L | 10.8-11.1 | 4.5-10.6 | 15-18 | 28-30 | 350°C / 662°F | -0.035 | |
| XGS30 | 10.8-11.1 | 9.8-10.6 | 18-25 | 28-30 | 350°C / 662°F | -0.035 | |
| XGS30H | 10.8-11.1 | 9.8-10.6 | >25 | 28-30 | 350°C / 662°F | -0.035 | |
| XGS32L | 11.1-11.4 | 4.5-10.8 | 15-18 | 30-31 | 350°C / 662°F | -0.035 | |
| XGS32 | 11.1-11.4 | 10.1-10.8 | 18-25 | 30-31 | 350°C / 662°F | -0.035 | |
| XGS32H | 11.1-11.4 | 10.1-10.8 | >25 | 30-31 | 350°C / 662°F | -0.035 | |
| XGS33L | 11.4-11.6 | 4.5-11 | 15-18 | 31-32 | 350°C / 662°F | -0.035 | |
| XGS33 | 11.4-11.6 | 10.4-11 | 18-25 | 31-32 | 350°C / 662°F | -0.035 | |
| XGS33H | 11.4-11.6 | 10.4-11 | >25 | 31-33 | 350°C / 662°F | -0.035 | |
| XGS34 | 11.6-11.8 | 4.5-11.2 | 15-18 | 32-33 | 350°C / 662°F | -0.035 | |
| XGS34H | 11.6-11.8 | 10.6-11.2 | >25 | 32-33 | 350°C / 662°F | -0.035 | |
| XGS35L | 11.7-12.2 | 4.5-11.2 | 15-18 | 33-35 | 350°C / 662°F | -0.035 | |
| XGS35 | 11.7-12.2 | 10.8-11.5 | 18-25 | 33-35 | 350°C / 662°F | -0.038 | |
| XGS35H | 11.7-12.2 | 10.8-11.5 | >25 | 33-35 | 350°C / 662°F | -0.038 | |
| Low Temperature Coefficient & High Temperature SmCo 2:17 Series | XGS20LT | 8.6-9.2 | 7.8-8.8 | >20 | 18-22 | 350°C / 662°F | ± 0.005 |
| XGS22LT | 9.0-9.5 | 8.2-9.2 | >20 | 20-24 | 350°C / 662°F | -0.01 | |
| XGS24G | 9.5-10 | 8.6-9.7 | >20 | 22-26 | 500°C / 932°F | -0.035 | |
| XGS22G | 9.0-9.5 | 8.2-9.2 | >20 | 20-24 | 550°C / 1022°F | -0.035 |
Understanding SmCo Grades and Families
Understanding the distinctions between the two main types of Samarium Cobalt magnets is crucial for selecting the appropriate material for a given application. Each series offers a unique balance of magnetic properties and thermal performance.
SmCo5 (1:5 Series)
The SmCo5 series represents the first generation of commercially available Samarium Cobalt magnets. These magnets are characterized by their excellent corrosion resistance, a property inherent to SmCo alloys. While they offer robust magnetic performance, their magnetic strength and maximum operating temperature ratings are generally slightly lower compared to the more advanced 2:17 series. The composition of SmCo5 magnets typically consists of approximately five parts Cobalt to one part Samarium. They remain a viable choice for applications where high corrosion resistance is critical and the absolute highest magnetic strength or extreme temperature performance is not the primary requirement.
Sm2Co17 (2:17 Series)
The Sm2Co17 series is recognized as the most common and advanced type of SmCo magnet available today. These magnets boast significantly higher magnetic strength, superior temperature resistance, and improved intrinsic coercivity compared to the 1:5 series. Their more complex composition includes additions of other elements such as copper, iron, and zirconium, which are carefully engineered to enhance their magnetic and thermal properties. With approximately 17 parts Cobalt to two parts Samarium, the 2:17 series is considered the top choice for most demanding applications requiring the highest performance and stability in challenging environments.
To facilitate an informed selection process, the detailed grade chart below provides a comprehensive overview of key properties for commercially available SmCo grades across both the 1:5 and 2:17 series. This breakdown empowers you to self-qualify your needs by clearly delineating the performance differences and trade-offs between the two series and across individual grades, such as how higher energy products often correlate with higher maximum operating temperatures in the 2:17 series. Our commitment to this level of detail reinforces our expertise and transparency in SmCo metallurgy and performance.
Critical Applications for Extreme Environments
Aerospace & Military
In the aerospace and military sectors, SmCo magnets are preferred due to their ability to withstand extreme temperatures, radiation, and vacuum environments while maintaining precise performance. Applications include: Guidance Systems, Precision Sensors & Actuators, Traveling-Wave Tubes (TWTs), and Satellite Components. The selection of SmCo in these industries implicitly communicates the capability to meet the most stringent quality and performance standards.
High-Performance Motors & Generators
SmCo magnets are vital in applications where motors operate under high heat, at high speeds, or require exceptional efficiency and compactness. Their stable magnetic output at elevated temperatures ensures consistent motor performance and longevity. Applications include: High-speed Servomotors, Turbo-machinery, and Electric Motors that operate in high-heat environments.
Oil & Gas Industry
The oil and gas industry presents some of the most challenging environments for equipment due to extreme temperatures, corrosive fluids, and high pressures. SmCo magnets are ideally suited for these harsh conditions, used extensively in Down-hole Sensors and Equipment where temperatures can routinely exceed 200°C.
Medical Science
In medical science, the need for biocompatibility, stability, and corrosion resistance is paramount, making SmCo magnets a preferred choice for various devices. Applications include: Implantable Devices, Pumps for medical fluids, and Surgical Tools where sterilization processes involve high temperatures.
Important Handling & Safety Information
Proper handling and machining of Samarium Cobalt magnets are critical for ensuring product integrity, maximizing performance, and promoting safety. SmCo magnets possess unique physical characteristics that necessitate specific precautions.
Extreme Brittleness: Samarium Cobalt magnets are exceptionally brittle. Unlike typical metals, they can easily chip, crack, or shatter if dropped, mishandled, or allowed to snap together forcefully. Such impacts can result in sharp shards, posing a potential hazard. Therefore, these magnets must be handled with extreme care, especially larger pieces, and should never be allowed to snap together or impact hard surfaces. Wearing appropriate personal protective equipment, such as safety glasses, is highly recommended during handling to mitigate the risk of injury from flying fragments. This proactive communication of the material's fragility helps manage customer expectations and prevents potential product damage or misuse.
Machining: Machining operations, such as drilling, cutting, or grinding, on Samarium Cobalt magnets must be performed *before* the magnet is fully magnetized. This is a highly specialized process that requires diamond tooling and expert knowledge to avoid damaging the magnet or creating hazardous dust. Attempting to machine a magnetized SmCo magnet or performing these operations without proper equipment is dangerous and will invariably destroy the magnet's magnetic properties and structural integrity. It is strongly advised that any required machining be specified during the custom order process, allowing the manufacturer to perform these operations under controlled conditions prior to magnetization. This detailed guidance on machining signals a deep understanding of the product's limitations and proper use, positioning the company as an authority that prioritizes customer success and safety.
Pinching Hazard: Strong magnets can exert immense attractive forces. There is a significant risk of severe injury to fingers or other body parts if magnets are allowed to slam together or attract to metal surfaces unexpectedly.
Pacemakers & Electronics: The powerful magnetic field generated by SmCo magnets can interfere with or damage sensitive electronic devices. It is crucial to maintain a safe distance from pacemakers, credit cards, mobile phones, hard drives, and all other electronics.
Children: Magnets are not toys and must be kept away from children. Swallowing magnets, especially multiple magnets, is a serious medical emergency that can cause serious and life-threatening internal injuries.
