Metallic Glass: The Key to More Efficient Electric Motors

Electric motors are ubiquitous, powering everything from e-bikes and drones to household appliances. While generally efficient, these motors aren’t without energy loss, which manifests as heat. This is particularly problematic in smaller drives, limiting performance, efficiency, and battery life. Researchers are now exploring metallic glass as a potential solution to reduce these energy losses and unlock significant improvements in device performance.

How Electric Motors Lose Energy

Electric motors function through magnetic fields. Rotating components within the motor interact with a constantly changing magnetic field, creating movement. This changing field affects the tiny magnetic areas within the metal of the motor, causing them to realign repeatedly. This constant realignment creates friction, dissipating energy as heat – a phenomenon known as iron loss. The smaller the motor, the more pronounced this inefficiency becomes, impacting devices like drones and e-bikes disproportionately.

The Role of Crystal Structure in Energy Loss

Traditional electric motors utilize iron alloys for key components. The atoms in these alloys are arranged in a regular, ordered crystal lattice. While providing structural integrity, this lattice hinders the realignment of magnetic areas when the magnetic field changes. The crystal structure acts as an obstacle, creating resistance and friction, ultimately leading to energy loss.

Metallic Glass: A Disordered Advantage

Metallic glass, unlike conventional metals, possesses a disordered atomic structure. Instead of a crystalline lattice, its atoms are arranged randomly, resembling the structure of glass. Despite this disordered arrangement, it remains a metal. This unique structure offers a significant advantage: the magnetic areas can move more freely when the magnetic field changes because there are no crystallites to impede their movement. This reduced friction translates to less energy loss and cooler operating temperatures.

The Impact of Increased Efficiency

Even minor improvements in electric motor efficiency can have a substantial cumulative effect, given the billions of devices that rely on them. Reduced energy loss leads to:

• Lower electricity consumption
• Extended battery life
• Reduced heat generation
• Increased range for mobile devices

“Just by replacing the material, we can reduce the energy consumption of many electrical devices,” explains Professor Ralf Busch of Saarland University. Battery-powered devices, in particular, stand to benefit, with e-bikes and drones potentially achieving longer runtimes or flight durations with the same battery capacity.

Manufacturing with Metal 3D Printing

Researchers are creating engine components from new alloys composed of 70 to 80 percent iron using metal 3D printing, specifically Laser Powder Bed Fusion. This process involves a laser melting fine metal powder layer by layer, with each layer approximately 50 micrometers thick – about half the thickness of a human hair – allowing for the precise creation of complex components entirely from metallic glass.

The Search for the Right Alloy

Identifying suitable alloys has been a complex undertaking. Researchers examined hundreds of different combinations, many of which proved unsuitable, either forming crystal structures upon cooling or being incompatible with 3D printing. After extensive testing, three alloys were identified that remain stable, glass-like, and printable.

European Research and Funding

This research is part of the AM2SoftMag project, a European Union-funded initiative receiving 3.5 million euros from the Horizon Europe Pathfinder program. Launched in 2022 and scheduled to conclude in February 2026, the project involves collaboration between research institutes and companies from Germany, Spain, Italy, and Poland. An industrial partner is producing the new engine components using 3D printing, while other institutes are investigating the magnetic properties of the materials.

From Research to Real-World Applications

Professor Busch’s research team at Saarland University has a long history of developing strong metallic glass alloys, some of which have even been tested in the unique environment of the International Space Station to better understand metal behavior. The current focus is on developing engine components that can be manufactured industrially, paving the way for more efficient devices and extended battery life thanks to metallic glass.

Key Takeaways

• Electric motors lose energy through iron losses caused by friction during magnetic realignment.
• Metallic glass reduces these losses due to its disordered atomic structure, allowing for easier magnetic area movement.
• Research at Saarland University demonstrates the potential of metallic glass alloys, produced using metal 3D printing, to significantly improve motor efficiency in devices like e-bikes and drones.

While metallic glass promises to enhance electric motor efficiency, parallel research efforts are focused on developing batteries with increased energy storage capacity. For example, a new lithium-air battery from Japan utilizes oxygen from the air and could theoretically achieve energy densities approaching those of gasoline engines.

Image: © Pasquale D’Angiolillo/UdS