Inductor insert compositions and methods

A composition useful in fabricating blocks or inserts for inductors comprising:

• (a) about 98 percent to about 99.5 percent by weight of a high purity, annealed electrolytically prepared iron powder;
• and
• (b) about 0.5 percent to about 2 percent of an insulating polymer epoxy resin binder;
• wherein said iron powder has a specific surface area of less than about 0.25.sup.2 /g and a carbon content of less than about 0.01 percent;
• and
• wherein said composition after pressing at at least about 30 Tsi demonstrates a maximum of 5 percent regression in permeability and a total core loss of less than about 0.8 to about 1.2 ohms between 10 KHz and 50 KHz.

A composition useful in fabricating blocks or inserts for inductors comprising:

• (a) about 98 percent to about 99.5 percent by weight of a high purity, annealed electrolytically prepared iron powder;
• and
• (b) about 0.5 percent to about 2 percent of an insulating flourocarbon polymer binder;
• wherein said iron powder has a specific surface area of less than about 0.25.sup.2 /g and a carbon content of less than about 0.01 percent;
• and
• wherein said composition after pressing at at least about 30 Tsi demonstrates a maximum of 5 percent regression in permeability and a total core loss of less than about 0.8 to about 1.2 ohms between 10 KHz and 50 KHz.

A method of preparing a block or insert for conductors comprising:

• (a) preparing a premix comprising an evaporable solvent, a polmer binder and
• a high purity, annealed electrolytically prepared iron powder;
• (b) substantially drying the product of step (a);
• (c) forming an insert from said substantially dried composition at a pressure of about 30 to about 50 Tsi;
• and
• (d) curing the formed insert at an elevated temperature of about 150 to about 500 degrees F.