Magnetics Business & Technology - September/October 2019 - 21

PRODUCT NEWS

amorphous structure. Because of the absence of crystalline
structures, amorphous alloys are magnetically soft providing
lower coercivity, lower core loss and higher permeability, with
high resistivity giving lower losses at higher frequencies. The
losses are among the lowest of any known magnetic materials.
Typical applications include medium-frequency transformer cores
in heating equipment, various toroidal cores, high-frequency
rectangular cut cores as output inductors and transformers,
and stators and rotors in high power density electric motors and
generators.
Available configurations and applications served include include
amorphous choke cores in standard and custom sizes with
plastic cases, epoxy coating, or varnish impregnated. The amorphous cut cores are available in standard ACC sizes along with
custom configurations. Typical applications are various choke
coils. Amorphous choke cores with air gap are also available in
standard and custom sizes with plastic cases, epoxy coating, or
varnish impregnated.
The nanocrystalline ribbon is based on Fe, Si, and B with additions of Nb and Cu. As with amorphous ribbon, it is produced by
a rapid cooling process into a thin ribbon, initially in the amorphous state, and then crystallized in a subsequent heat treatment
around 500-600 degrees Centigrade. This results in an extremely
fine-grained microstructure with grain sizes of 10 nanometers,
hence the name nanocrystalline.

low magnetostriction, both of which are prerequisites for high
magnetic permeability with high magnetic flux density and good
thermal stability. Nanocrystalline ribbon can replace silicon steel,
permalloy, and ferrite, as various forms of high frequency cores
used in switching power supplies, control transformers, reactors,
magnetic amplifiers, EMC filers and differential mode inductors.
Custom nanocrystalline cores are also available. Typically used
for large toroidal power transformers, current transformers in
power systems, current transformers, common mode chokes,
and MAG-AMPS. These cores are available encased in a plastic
core cup, epoxy coated, or varnish impregnated. As with the
amorphous choke cores with air gap, the nanocrystalline cores
can be configured with an air gap for Hall Effect devices and applications.
DC Immunity Composite Cores are made up of both nanocrystalline ribbon and amorphous ribbon material, allowing the core to
operate effectively as a current transformer under DC current
conditions. Typical applications include DC current immunity
transformers in electronic energy meters and watt-hour meters
as well as metering transformers in electronic power systems.
The Perm-alloy Ribbon is a highly magnetic nickel-molybdenumiron alloy, with roughly 80% nickel, 15% iron, and 5% molybdenum content making it particularly useful as a magnetic core
material in certain electrical and electronic equipment.
For more info, see www.mhw-intl.com.

The nanocrystalline alloys combine low magnetic anisotropy and

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Magnetics Business & Technology - September/October 2019

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