Magnetic Materials
High-Quality Alnico Magnets
When precision, durability, and reliability are critical, Thomas & Skinner’s Alnico magnets deliver unparalleled performance. As a trusted leader in high-performance magnet manufacturing with over a century of expertise, we are at the forefront of innovation, providing customized solutions for a variety of industries and defense applications worldwide. Here’s why organizations choose our Alnico magnets:
Unmatched Performance in Challenging Environments
Alnico magnets are known for their excellent temperature stability and resistance to demagnetization. Our magnets maintain their strength and effectiveness in extreme industrial conditions or critical defense operations, ensuring consistent and reliable performance. Whether for aerospace, medical devices, or custom applications, our Alnico magnets are designed to deliver peak performance.
Versatile Applications Across Industries
Our Alnico magnets are favored for their stability at high temperatures, excellent resistance to demagnetization, and broad field capabilities. These qualities make them ideal for a wide array of applications, including:
- Electric Motors
- Generators
- Sensors
- Measuring Instruments
- Precision Defense Technologies
- Magnetic Separators
- Aerospace Systems
- Audio Equipment
- Medical Devices
- Electric Motors
- Generators
- Sensors
- Measuring Instruments
- Precision Defense Technologies
- Magnetic Separators
- Aeorspace Systems
- Audio Equipment
- Medical Devices
Whatever your needs, Thomas & Skinner has the expertise to provide the right magnet for your specific application.
What is the Process for Manufacturing Alnico Magnets
Alnico magnets are manufactured either by casting or sintering:
- Cast Alnico is produced by conventional foundry methods using resin-bonded sand molds
- Sintered Alnico magnets are formed using powdered metal manufacturing methods. Sintering Alnico is suitable for complex geometries.
Most Alnico produced is anisotropic, meaning that the magnetic direction of the grains is oriented in one direction. This orientation is achieved via heat treatment after casting or sintering. The process involves heating the cast or sintered part above its Curie temperature and then cooling it at a controlled rate in the presence of a strong directional magnetic field. Final shaping of the Alnico materials is achieved by abrasive grinding and cutting where close tolerances are required.
Alnico Magnet History
A big step in the evolution of the permanent magnet materials used today came in the 1930’s with the development of Alnico magnets. In 1931, T. Mishima discovered that an alloy of iron, nickel, aluminum had a much higher coercivity than the best steel magnets of the time. Further research created Alnico, a term referring to a series of permanent magnet alloys which in addition to iron are composed primarily of aluminum (Al), nickel (Ni) and cobalt (Co). Various Alnico grades with differing magnetic properties can be achieved by modifying the chemistry and manufacturing process. Today’s composition of Alnico alloys is typically 8–12% Al, 15–26% Ni, 5–24% Co, up to 6% Cu, up to 1% Ti, with the balance being Fe. In addition to varying the alloy composition, specialized casting techniques can be used to achieve unique crystalline grain orientation. Examples of this are Alnico 5-7 and 9. Once magnetized, Alnico magnets have between 5 and 17 times the magnetic force of magnetite or lodestone, a naturally occurring magnet which can attract iron.
Alnico magnets have the benefit of having the lowest temperature coefficient, or best performance at high temperature, of all the permanent magnet materials. Plus, they can be calibrated and have high residual induction. Before the development of rare earth magnets in the 1970’s, Alnico was the strongest type of permanent magnet. Since that time, many applications using Alnico have replaced it with less expensive or more powerful types of magnets. However, the fact that Alnico can be used in very high temperatures (up to 930°F or 500°C) make them indispensable in certain applications. Alnico magnets are also ideal for corrosive applications and are commonly used for various types of sensors. They typically have a higher maximum energy product than ceramic magnets, but a lower maximum energy product than rare-earth magnets.
