Amorphous & Nanocrystalline Magnetic Cores

Tape wound cores are made from winding thin strips of high-permeability metallic-glass materials such as nickel-iron or silicon-iron alloys and then annealing them under heat and pressure. These cores play a critical role in many electronics applications and are available in two primary varieties: 

  • Nanocrystalline cores. Nanocrystalline cores are made from metallic-glass materials with a crystalline structure. These cores are distinguished by superior permeability coupled with low power loss and high saturation. These advantages have made them more popular than any other core material for novel applications.
  • Amorphous cores. Amorphous cores are made from similar metallic-glass alloys, but with randomly arranged, noncrystalline structures. These cores offer high resistivity and low loss at high frequencies.

MK Magnetics, Inc. was founded in response to industry demands for reliable custom tape wound cores. Since the beginning, our mission has been to provide the highest quality tape wound cores, including highly customizable amorphous and nanocrystalline options for specialized applications. Today, we proudly offer an extensive range of amorphous and nanocrystalline cores, along with the capability to develop fully custom processes for non-standard orders of any size or complexity. 

Nanocrystalline Core Race track

Nanocrystalline Core Race track

Amorphous C-Core Tape Wound

Amorphous C-Core Tape Wound

Machined Angled Nanocrystalline C-Core

Machined Angled Nanocrystalline C-Core

What are Amorphous and Nanocrystalline Cores?

Amorphous and nanocrystalline cores are among the most innovative materials available for low-loss, high-permeability cores. Although they differ in structure and performance characteristics, they both leverage metallic-glass alloys to improve electrical performance versus standard ferrite cores as well as silicon steel alloys.

Amorphous Cores

Amorphous cores get their name from their random atomic structure, which differs from the ordered, crystalline structure typical of metal or nanocrystalline cores. The unstructured arrangement of atoms increases resistivity compared to crystalline alloys, improving frequency response and efficiency, and allowing for extremely low loss at higher frequencies. 

Nanocrystalline Cores

The crystalline atomic structure of a nanocrystalline core creates superior magnetic properties, including high saturation and very high permeability across a wide frequency range. Nanocrystalline alloys also exhibit low AC loss and high efficiency, even at high temperatures. Nanocrystalline cores can also be annealed under magnetic fields to align the magnetic domains and provide superior magnetic properties.

Amorphous and Nanocrystalline Core Industry Applications

Amorphous and nanocrystalline cores are useful in electronics applications across diverse industries. Sectors that take advantage of tape wound cores include:

  • Aerospace
  • Automotive
  • Military
  • Medical
  • Energy Storage and Generation
  • Oil and Petrochemical
  • Telecommunications

Innovative tape wound materials help clients in these industries optimize magnetic performance across varied, demanding applications.

Amorphous Core Industry Applications

Amorphous magnetic cores allow OEMs to decrease component size and reduce weight while still improving electrical performance. These benefits make amorphous cores an excellent choice for high-frequency applications such as inverters, adjustable speed drives, and both switched-mode and uninterruptible power supplies (SMPS and UPS). Additional applications include:

  • AC and DC transformers
  • Inductors
  • Common mode and differential mode chokes
  • Magnetic amplifiers

Nanocrystalline Core Industry Applications

Applications for nanocrystalline cores closely resemble those for amorphous cores. The choice between an amorphous and nanocrystalline material for a given application depends on the specific environmental and industrial constraints. The high permeability, low power loss, and high saturation of nanocrystalline cores improve performance across:

  • SMPS and UPS
  • Inverters
  • EMC filters
  • Frequency converters
  • AC and DC transformers
  • Inductors
  • Common mode and differential mode chokes
  • Magnetic amplifiers

Advantages of Using Amorphous & Nanocrystalline Cores

When choosing between amorphous and nanocrystalline cores, it’s important to consider each materials’ unique advantages. When in doubt, the experts at MK Magnetics can help you determine which core material is best for your application.

Advantages of Amorphous Cores

The benefits of amorphous cores are rooted in their random atomic structure, which lacks the sort of structural anomalies that can interfere with magnetic performance. Key advantages of amorphous materials include:

  • Reduced no-load losses. A tape wound core made from amorphous material can achieve no-load loss reductions of up to 30% compared to silicon steel. These performance enhancements come from the random grain structure and high permeability, which serve to reduce both hysteresis loss and eddy current loss.
  • Improved overload capacity. As a result of reduced losses, amorphous tape wound cores generate less heat than conventional materials. Not only does this decrease wear on insulation, but it also improves overload capacity. 
  • Heightened efficiency. Another benefit of reduced no-load loss is a more favorable efficiency distribution. The significant efficiency improvements of amorphous cores help users reduce energy loss and decrease operating costs over the long term.
  • Limited environmental impact. Along with increased efficiency comes reductions in CO2 and SO2 emissions. As a result, amorphous cores are often more environmentally friendly than conventional alternatives. 

Advantages of Nanocrystalline Cores

Nanocrystalline materials were historically limited by their high cost and narrow widths. However, modern nanocrystalline materials like Finemet® FT-3W have eliminated these challenges, making nanocrystalline cores more competitive in both price and versatility. Finemet® and similar nanocrystalline materials bring the following benefits:

  • High magnetic induction. Like amorphous materials, nanocrystalline alloys have higher permeability than any other magnetic material. Their impressive induction not only improves performance but also allows for reduced component size.
  • High saturation. Nanocrystalline cores have the high saturation magnetic induction strength to handle high-current applications with strong interference.
  • Flexibility. The nanocrystalline production process is extremely flexible, allowing manufacturers to achieve varied frequency, impedance, and filtering characteristics.
  • Temperature stability. Nanocrystalline alloys exhibit excellent stability when exposed to temperature fluctuations, with a near-linear performance change. Compared to a ferrite core, a nanocrystalline core has a significantly higher Curie temperature and a slower, more predictable rate of change, making nanocrystalline a better choice for applications with significant thermal demands.

Magnetic performance. The structure of nanocrystalline allows for the arrangement of the magnetic domains by annealing the cores under the influence of specialized fields. This process can affect the B-H curve of the material for specific applications.

High-Quality Custom Cores

MK Magnetics specializes in custom cores formed to clients’ precise specifications. Amorphous and nanocrystalline cores can be configured with C, E, Toroid, and bar profiles, and in both standard and custom sizes. Further, our amorphous and nanocrystalline manufacturing processes leverage specialized annealing and bonding systems tailored to each design’s required frequency. These highly efficient processes can deliver over 30% lower loss than competing cores, depending on material and frequency. 

Our team has a long track record of meeting customer challenges with innovative, individualized solutions. Whatever your application, we are ready to apply our successful process to overcome your electronic and magnetic obstacles.

MK Magnetics Brings the Future of Energy Storage to Your Business

With their high permeability and low power loss, nanocrystalline and amorphous cores represent the future of energy storage. At MK Magnetics, we’ve delivered cutting-edge core solutions to our clients since 2003, and we are ready to do the same for you. Browse our case studies to learn more about how we tackle client challenges via a solutions-focused, custom manufacturing process. For more information about our amorphous and nanocrystalline tape wound cores, contact us or request a quote today.