Powder metallurgy consists of compacting a mixture of metal powders in a tool or mold that has the negative shape of the part, and sintering the compacted preform in an oven at a temperature lower than the melting point of the base metal.

The feedstock for a soft magnetic sintered component is a powder of pure iron, alloys or mixtures of pure iron with phosphorus, silicon, nickel or chromium, or micro-insulated iron. The mixture or alloy has the chemical composition of the final material.

The resulting powder mixture is compacted within a tool or mold that has the negative shape of the final part, and pressure is applied according to the final density to be reached.

The compacts are sintered in a furnace. This operation consists in heating the compacted part to a temperature between 1,100 and 1,300 °C under conditions of controlled atmosphere and time. The high temperature causes the powder particles to weld together and the alloying elements to diffuse. The encapsulated materials are not sintered but cured at temperatures between 450 and 650ºC.

The result of this process is a magnetically and mechanically functional metal part of high dimensional accuracy and a controlled level of microporosity.

Soft magnetic powder metal components sometimes require complementary manufacturing operations. The aim is to modify one or more characteristics to make the component functional in the unit in which it is mounted.

• Porosity sealing. This consists of filling the pores with a chemical product. Resin tightens it and copper increases its mechanical strength.
• Sizing. This consists of re-pressing the sintered part in a rigid tool to increase its density, improve its dimensional accuracy and roughness, and/or create relief details.
• Machining. Turning, grinding, milling, drilling, threading, honing, polishing, etc. are used to obtain shapes or tolerances that cannot be achieved directly by compacting.
• Annealing. This is applied to restore or improve the magnetic properties of the original material after cold work deformation or mechanical action. Annealing can be used for stress relief, recrystallization or grain growth, depending on the properties that must be achieved.
• Deburring and cleaning. Tumbling, shot blasting, brushing, polishing, ultrasonic cleaning, etc.
• Coatings. Zinc, chrome and nickel plating, phosphating, metallizing, polytetrafluoroethylene coating, etc.
• Joining to other components. Welding, brazing, sinter-bonding, fitting, glueing, riveting, overmolding, etc.