Samarium Cobalt magnets: What is it and how is it made
Published: 2023-04-17 15:04:56 • Daniel Gårdefelt
Samarium Cobalt (SmCo) magnets are a form of rare earth magnets characterized by their exceptional magnetic properties and high demagnetization resistance. These powerful magnets are used in a wide range of applications, from aerospace and automotive to medical and consumer electronics. In this blog post, we will examine Samarium Cobalt magnets in detail, examining their manufacturing process, properties and various applications.
Samarium Cobalt magnets were first created in the early 1970s at Wright-Patterson Air Force Base in Ohio by Dr. Karl Strnat and Dr. Alden Ray. They were looking for materials with extraordinary magnetic properties, and their discovery of SmCo magnets marked a major advance in magnet technology.
The production process of samarium cobalt magnets involves several phases, including raw material preparation, alloy formation, milling, pressing, sintering and finishing.
1. Raw materials: Samarium, a rare earth metal, and cobalt, a transition metal, are the primary components of SmCo magnets. SmCo alloy is created by combining these elements in precise proportions. A small amount of other materials are also used in the mixture. You can see which materials this is under Samarium Cobalt on our magnet facts page.
2. Alloying: At high temperatures, samarium and cobalt fuse together to form an alloy. The liquid metal is then rapidly cooled to form a solid ingot.
With the help of specialized milling equipment, the solid ingot is reduced to a fine powder. This substance is the raw material from which magnets are made.
3. Pressing: Using high-pressure presses, the SmCo material is compressed into the desired magnet shape. In this phase, a magnetic field is used to align the magnetic domains in the material, ensuring that the final magnet will have the desired magnetic properties.
4. Sintering: The pressed magnet is heated to high temperatures in a controlled atmosphere during the sintering procedure. This procedure fuses the individual components into a uniform and dense magnet.
5. Finishing: To achieve the desired dimensions and tolerances, the sintered magnet is ground, cut or machined. The magnet is then coated or plated to prevent corrosion and improve its appearance.
The main features and benefits of samarium cobalt magnets:
1. High magnetic strength: SmCo magnets have strong magnetic properties, making them ideal for applications that require magnets with exceptional performance.
2. Stability at high temperatures: SmCo magnets retain their magnetic properties at high temperatures, making them suitable for use in extreme environments.
3. Corrosion resistance: SmCo magnets have good corrosion resistance, reducing the need for protective coatings or plating.
4. Low Temperature Coefficient: The magnetic properties of SmCo magnets are less affected by temperature fluctuations, ensuring stable performance over a wide temperature range.
5. High demagnetization resistance: Samarium cobalt has the highest coercivity among all the magnetic materials. Coercivity, also called magnetic coercivity, coercive field or coercive force, is a measure of the ability of a ferromagnetic material to resist an external magnetic field without being demagnetized
Due to their remarkable properties, Samarium Cobalt magnets are used in a wide range of applications, including:
1. Aerospace and Defense: SmCo magnets are used in aircraft and satellite systems, missile guidance and control systems.
2. Vehicles: SmCo magnets are integral components of electric vehicle motors, sensors and actuators.
Medical equipment, such as MRI scanners and surgical instruments, use SmCo magnets.
These magnets are found in headphones, speakers and other home electronics.
We can thus state that samarium-cobalt magnets are a strong and versatile magnetic material with unique properties that make them useful for a variety of applications.