Editing Magnetic core (section)

==== Special alloys ====
A family of specialized alloys exists for magnetic core applications. Examples are [[mu-metal]], [[permalloy]], and [[supermalloy]]. They can be manufactured as stampings or as long ribbons for tape wound cores. Some alloys, e.g. [[Sendust]], are manufactured as powder and [[sintering|sintered]] to shape.

Many materials require careful [[heat treatment]] to reach their magnetic properties, and lose them when subjected to mechanical or thermal abuse. For example, the permeability of mu-metal increases about 40 times after [[annealing (metallurgy)|annealing]] in hydrogen atmosphere in a magnetic field; subsequent sharper bends disrupt its grain alignment, leading to localized loss of permeability; this can be regained by repeating the annealing step.