In modern industrial systems, magnets play a crucial role. From miniature sensors to large motors, from medical devices to aerospace applications, magnets are ubiquitous. However, with numerous magnet materials available, selecting the right type for specific applications has become a significant challenge for engineers and designers.

As materials capable of generating magnetic fields, magnets serve essential functions across industries:

• Energy conversion: Motors, generators, and transformers rely on magnets for electromagnetic energy conversion.
• Information transmission: Magnetic recording and sensing devices utilize magnetic properties for data storage and transfer.
• Motion control: Magnetic levitation and drive technologies enable precise movement control.
• Medical applications: MRI scanners use powerful magnetic fields for internal imaging.
• Industrial automation: Magnetic switches and sensors facilitate position detection and limit control.

Characteristics: NdFeB magnets represent the strongest commercial permanent magnets, with magnetic energy products reaching 30-52 MGOe. They combine high intrinsic coercivity (10-35 kOe) with excellent cost performance.

Applications: MRI systems, magnetic separators, audio devices, wind turbines, electric vehicle motors, and precision instruments.

Limitations: Temperature sensitivity above 80°C, susceptibility to corrosion, and brittleness requiring protective coatings.

Characteristics: These alloy magnets demonstrate exceptional temperature stability (up to 540°C), superior corrosion resistance, and high mechanical strength.

Applications: High-temperature sensors, audio equipment (guitar pickups, microphones), aerospace instrumentation.

Limitations: Lower magnetic strength compared to rare-earth magnets and susceptibility to demagnetization.

Characteristics: Cost-effective oxide magnets with good corrosion resistance and demagnetization resistance, though with relatively weak magnetic properties.

Applications: Refrigerator seals, speaker systems, educational magnets, and low-cost sensors.

Limitations: Brittle material properties and temperature sensitivity above 100°C.

Characteristics: High-performance rare-earth magnets with exceptional thermal stability (-273°C to 350°C) and corrosion resistance.

Applications: Aerospace systems, downhole drilling tools, high-temperature motors, and precision instruments.

Limitations: High material costs and brittle mechanical properties.

Characteristics: Flexible composite materials combining ferrite powder with rubber binders, allowing custom shapes and sizes.

Applications: Refrigerator seals, educational products, advertising displays, and flexible mounting solutions.

Limitations: Weak magnetic strength and temperature sensitivity.

• Remanence (Br): Residual flux density after magnetization
• Coercivity (Hcb): Resistance to demagnetization
• Intrinsic Coercivity (Hcj): Material's inherent resistance to demagnetization
• Maximum Energy Product (BHmax): Peak magnetic energy storage capacity
• Curie Temperature (Tc): Thermal limit for magnetic properties

Research focuses on new rare-earth alternatives (CeFeB, SmFeN), reduced rare-earth content formulations, and nanocomposite materials to enhance performance while lowering costs.

Advanced powder metallurgy techniques, rapid solidification processes, and novel coating technologies aim to improve magnetic properties and durability.

Growing adoption in renewable energy systems (wind power, EVs), advanced robotics, and biomedical devices demonstrates magnets' expanding technological role.