Patent ID: 8177926

Claim:
A method for the preparation of an amorphous Fe 100-a-b P a M b alloy, in the form of a free-standing foil, wherein: said foil has an average thickness in the range 20 μm-250 μm; in formula Fe 100-a-b P a M b , a is a number ranging from 13 to 24, b is a real number ranging from 0 to 4, and M is at least one transition element other than Fe; the alloy has an amorphous matrix in which nanocrystals having a size lower than 20 nm may be embedded, and the amorphous matrix occupies more than 85% of the volume of the alloy, wherein said method comprises electrodeposition of an alloy deposit using an electrochemical cell having a working electrode which is the substrate for alloy deposition and an anode, said electrochemical cell contains an electrolyte solution which acts as a plating solution and a dc current or a pulse current is applied between the working electrode and the anode, the plating solution is an aqueous solution with a pH ranging from 0.8 to 2.5 and a temperature ranging from 60° C. to 105° C., which contains: an iron precursor at a concentration ranging from 0.5 to 2 M, selected from the group consisting of a clean iron scrap, iron, pure iron, and a ferrous salt, said ferrous salt selected from the group consisting of FeCl 2 , Fe(SO 3 NH 2 ) 2 , FeSO 4 and mixtures thereof; a phosphorus precursor selected from the group consisting of NaH 2 PO 2 , H 3 PO 2 , H 3 PO 3 , and mixtures thereof, at a concentration ranging from 0.035-1.5 M; and optionally a M salt at a concentration ranging from 0.1 to 500 mM; a dc or pulse current is applied between the working electrode and the anode with a density ranging from 3 to 150 A/dm 2 ; wherein the working electrode and the anode are static parallel plate electrodes, and the velocity of the aqueous plating solution is of the order of 100 to 320 cm/s and the gap between the static parallel electrodes is from 0.3 cm to 3 cm.