In addition for very large core requirements these large shapes can be configured and bonded for a number of custom.
Mu core metal.
Mu metal offers exceptionally high initial and maximum permeability with minimum hysteresis loss.
More recently mu metal is considered to be astm a753 alloy 4 and is.
Mu metal is a nickel iron soft ferromagnetic alloy with very high permeability which is used for shielding sensitive electronic equipment against static or low frequency magnetic fields it has several compositions.
It also has very low coercive force hc very low core losses and a low remanence br.
Mumetal chemical composition in weight nickel ni 80 82 molybdenum mo 3 5 6.
One such composition is approximately 77 nickel 16 iron 5 copper and 2 chromium or molybdenum.
Kool mu shapes e cores toroids u cores eq cores lp cores eer cores and blocks are available in various sizes.
Available as stress annealed soft annealed for ease of fabrication or final annealed for maximum permeability.
However cores may be supplied up to 47 25 1200mm diameter with reduced magnetic performance subject to a minimum build up limitation of 5 of the diameter.
These shapes compare favorably with gapped ferrites powdered iron and silicon steel cores.
Core maximum outside diameter is 35 5 900mm.