Why Are Nanocrystalline Ribbons Getting Thinner And Thinner?

Why Are Nanocrystalline Ribbons Getting Thinner and Thinner?

1. The Key Reason: Reducing Eddy Current Loss

Nanocrystalline ribbon is a highly conductive metallic material. When exposed to a high-frequency alternating magnetic field, eddy currents are induced inside it - similar to electric currents circulating unnecessarily within the material. These currents dissipate as Joule heat, causing wasted energy (known as eddy current loss), which is the biggest drawback in high-frequency applications.

The critical point: eddy current loss is proportional to the square of the ribbon thickness. Simply put, the thinner the ribbon, the shorter the eddy current path and the smaller the cross-sectional area, resulting in much weaker eddy currents and drastically reduced loss. This is the core reason why ribbons are continuously made thinner.

 

2. Ultra-Thin Ribbons Are Essential for High-Frequency Applications

The power electronics industry is rapidly moving toward higher frequencies. Whether in EV chargers, on-board power supplies, photovoltaic inverters, or high-frequency switching power supplies, higher operating frequencies enable smaller sizes and higher efficiency.

However, as frequency increases, the alternating magnetic field changes faster, intensifying eddy current effects and driving up losses. Only thinner nanocrystalline ribbons can maintain high energy conversion efficiency and meet the requirements of these advanced devices.

 

3. More Uniform Annealing for Ultra-Thin Ribbons

To achieve optimal performance, nanocrystalline ribbon must undergo annealing - a heat treatment that forms a uniform and stable nanocrystalline structure. Thickness directly affects annealing quality.

Thinner ribbons allow faster and more uniform heat penetration, fully eliminating internal stress from manufacturing. This maximizes permeability and reduces hysteresis loss, ensuring consistent performance. In contrast, thicker ribbons often suffer from uneven heating, leading to inconsistent internal and external properties that degrade overall device performance.

 

4. Ultra-Thin Ribbons Enable Smaller, More Compact Cores

With the same core cross-sectional area, thinner ribbons allow more layers during winding, resulting in a higher stacking factor and a denser structure.

A denser core reduces internal gaps, improves magnetic circuit efficiency, and lowers magnetic flux leakage. More importantly, for the same power rating, a compact core significantly reduces size and weight, supporting the industry trend toward miniaturization and high power density.

 

5. Better Heat Dissipation

Ultra-thin nanocrystalline ribbons have extremely short heat conduction paths. Heat generated inside the core (primarily from eddy current loss) dissipates quickly to the surface and into cooling systems, avoiding overheating.

This preserves magnetic performance under operating conditions and improves the stability and service life of power electronic devices.

 

Summary

The trend toward thinner nanocrystalline ribbons fundamentally responds to the industry shift toward high frequency and miniaturization. Reducing thickness lowers eddy current loss, boosts efficiency, improves annealing uniformity, increases core compactness, and enhances thermal performance. The result is more energy-efficient, stable, and compact devices ideal for advanced power supplies and new energy equipment.