Flash annealing of amorphous alloys

A new method to improve the magnetic properties of amorphous alloys by fast annealing is introduced. The zero-magnetostrictive Fe4.7Co70.3Si15B10amorphous alloy was flash-annealed by the resistive heating of short (of the order of a second) electric current pulse flowing through the sample. The heating/cooling rate was of the order of 10⁴-10⁵K/min. This enables the sample to be annealed at much higher temperatures (estimated 800°C) without causing crystallization, compared to the conventional annealing methods. The maximum permeability of a zeromagnetostrictive alloy obtained by this method is higher than those obtained by the conventional annealing, with the additional benefit of smaller disaccomodation effect.