Samarium cobalt magnets are primarily composed of elements such as samarium (Sm), cobalt (Co), copper (Cu), iron (Fe), and zirconium (Zr). Structurally, they are divided into two types: Sm2Co17 and Sm1Co5.
Samarium cobalt magnets are the best temperature-resistant permanent magnetic materials and possess many excellent magnetic properties, such as high remanence, high coercivity, very low-temperature coefficients, and strong corrosion resistance.
Types of Samarium Cobalt Magnets
There are two main types of samarium cobalt magnets: Sm1Co5 and Sm2Co17. Different types of samarium-cobalt magnets have various grades.
Sm2Co17 Magnets
Sm₂Co₁₇ is a high-performance rare-earth permanent magnetic material, belonging to the second generation of samarium-cobalt permanent magnets. Sm₂Co₁₇ is mainly composed of samarium (Sm), cobalt (Co), iron (Fe), copper (Cu), and zirconium (Zr), with a stoichiometric ratio of approximately Sm:Co = 2:17. It has a rhombohedral crystal structure, which endows it with excellent magnetic properties and high-temperature stability.
Sm₂Co₁₇ magnets are highly brittle, difficult to machine, and prone to chipping or cracking. Precision machining typically requires the use of diamond tools.
Sm1Co5 Magnets
The chemical formula is SmCo₅, composed of samarium (Sm) and cobalt (Co) in a 1:5 atomic ratio, with a hexagonal crystal structure (CaCu₅ type). Its structure is simple, with extremely strong magnetocrystalline anisotropy and high coercivity. It exhibits excellent corrosion resistance and oxidation resistance, allowing it to be used in general environments without surface treatment.
Production Process of Samarium Cobalt Magnets
The production process for samarium-cobalt magnets: Raw material preparation → Melting and ingot casting → Powder production → Pressing → Sintering and tempering → Magnetic property testing → Grinding → Cutting and machining → Final Products
Advantages of Samarium Cobalt Magnets
Temperature Resistance
Although the magnetic properties of samarium-cobalt magnets are inferior to neodymium-iron-boron magnets, they have a wider operating temperature range and superior temperature coefficients.
The temperature coefficient of remanence (Br) for samarium-cobalt magnets is only -0.03-0.05%/°C, much lower than NdFeB’s -0.11%/°C. This means SmCo loses less field strength per degree of temperature increase compared to NdFeB. Sm2Co17 has a maximum temperature of 350°C.
Samarium-cobalt magnets perform well not only at high temperatures but also maintain their magnetism even at temperatures below absolute zero (-273°C), making them popular in low-temperature applications.
Corrosion Resistance
Neodymium-iron-boron magnets have a high iron content, making them prone to oxidation and corrosion. Surface treatment is essential, and the magnet’s lifespan largely depends on the coating’s effectiveness.
Samarium-cobalt magnets have a lower iron content and are mostly composed of elements that resist oxidation and corrosion. Generally, they don’t require surface treatment unless used in harsh environments or for aesthetic purposes.
Applications of Samarium Cobalt Magnets
Samarium cobalt magnets are most commonly used in applications requiring high-temperature operation, such as generators, pump couplings, sensors, motors, marine applications, and in automotive, aerospace, military, food, and manufacturing industries.
Samarium Cobalt Magnets Manufacturer
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Gtekmagnet & Duramag & First4magnets & Smk-magnet. & Stanfordmagnets
