Samarium Cobalt Magnets Retain Their Value in High-Temperature Applications Amid Cobalt Supply Concerns

A recent development in the U.S. cobalt supply chain has drawn attention to the cost of cobalt-containing materials. On October 6, 2026, Intermestic EB5 Fund II announced USCIS approval for a $64.8 million EB-5 investment offering linked to EVelution Energy's planned cobalt processing facility in Yuma County, Arizona. The approval supports a proposed investment route for the project rather than representing a direct federal grant.

For buyers of samarium cobalt (SmCo) magnets, developments in cobalt processing matter because cobalt is a major component of both SmCo 1:5 and SmCo 2:17 alloys. Yet the main reason these magnets remain valuable is their magnetic performance in high-temperature environments where conventional neodymium magnets may be less suitable.

High-Temperature Performance of Samarium Cobalt Magnets

Samarium cobalt magnets generally have a lower maximum energy product than high-performance sintered neodymium (NdFeB) magnets at room temperature. Their advantage lies in their relatively low reversible temperature coefficient of remanence and their ability to maintain useful magnetic performance at elevated temperatures.

For standard SmCo grades, the reversible temperature coefficient of remanence is typically around −0.03% to −0.05% per °C, depending on the alloy and grade. Magnetic flux decreases as temperature rises, but the change is relatively small compared with many conventional NdFeB grades.

Selected SmCo 2:17 magnets can operate at temperatures around 300°C or higher, subject to grade, magnet geometry and magnetic circuit conditions. This makes SmCo a practical option for compact motors, sensors and other components exposed to sustained heat.

High-temperature performance still requires careful grade selection. Engineers must consider both reversible magnetic changes and the possibility of irreversible demagnetization under operating conditions.

SmCo 1:5 vs. SmCo 2:17: Properties and Cobalt Content

Samarium cobalt magnets are commonly divided into two main series: SmCo 1:5 and SmCo 2:17.

SmCo 1:5 grades are often selected for applications requiring high coercivity and reliable magnetic performance at elevated temperatures. Many standard grades have maximum operating temperature ratings around 250°C.

SmCo 2:17 grades generally offer higher remanence and maximum energy product, with selected grades suitable for operation at approximately 300–350°C. Their properties depend on alloy composition, heat treatment and the required operating conditions.

Both series contain substantial amounts of cobalt, so raw material costs can affect magnet pricing. However, the actual cobalt content varies with the alloy formulation. SmCo 2:17 should not automatically be assumed to contain more cobalt by weight than SmCo 1:5.

For applications operating between 200°C and 250°C, comparing suitable grades from both series can help balance magnetic performance, temperature capability and material cost.

Corrosion Resistance and Applications of SmCo Magnets

Corrosion resistance is another important advantage of samarium cobalt magnets. Unlike sintered NdFeB magnets, many SmCo components can be used without protective plating in suitable operating environments.

This can simplify component design where coating thickness, temperature resistance or long-term surface performance must be considered. Additional protection may still be necessary in particularly aggressive environments.

Typical applications include aircraft actuators, downhole instruments, aerospace magnetic components, high-temperature sensors and precision measuring equipment.

In these applications, SmCo magnets are selected not simply for magnetic strength but for their combination of temperature capability, resistance to demagnetization and corrosion performance.

Cobalt Supply, Quality Control and Custom SmCo Magnets

New cobalt processing projects may provide additional supply options over time, but their impact on material availability and pricing will depend on successful financing, construction and commercial production.

For magnet buyers, consistent magnetic performance remains as important as raw material cost. When specifying samarium cobalt magnets, it is useful to confirm the required magnetic grade, operating temperature range, dimensional tolerances and acceptance criteria for magnetic moment or other magnetic properties.

We manufacture sintered samarium cobalt magnets in SmCo 1:5 and SmCo 2:17 series, including discs, cylinders, rings, blocks and custom shapes. Temperature-compensated and high-temperature grades can be discussed according to application requirements.

For aerospace, downhole and precision instrument applications, please provide the operating temperature range, technical drawings, magnetic performance requirements and estimated order quantity.

Contact us with your specifications to discuss the appropriate SmCo grade and testing requirements for your application.