AMES offers in its catalog more than 25 types of sintered soft magnetic iron-based materials, which use a wide variety of alloying elements, such as P, Si, Ni, Cr or Mn. These materials reach a saturation induction up to 2.05 T, a maximum permeability up to 75,000, and a minimum coercive force of 2 A/m.

The material is selected based on the working frequency, the induction that the component must provide, the required response speed, and the degree of saturation at which it works. The final properties of the material are regulated based on its chemical composition, density, processing conditions, and possible annealing.

• Pure iron. It is the most economical material. It is usually used when the piece works under pure induction at saturation in circuits excited by permanent magnets or by direct or pulsating current with a frequency of less than 10 Hz, reaching up to 200 Hz in low-power circuits.
• Fe-0,45%P. It provides greater permeability and lower coercive force than pure Fe, so it is used in similar applications that require a more powerful and/or faster response and less inertia. It has a higher elastic limit and greater hardness than pure Fe.
• Fe-3%Si. It has greater permeability and lower coercive force than Fe-0.45%P, which makes this material interesting when the circuit does not work at saturation or needs to work at quicker response and/or detachment speed. Its greater resistivity allows it to work at a higher frequency, up to 100 Hz in circuits excited with alternating or pulsating current, and can reach 1 KHz in low-power circuits.
• Fe-Ni. It is the material with the highest permeability and the lowest coercive force. For this reason, it is used in highly sensitive equipment, which requires a very fast response from the component or is excited by a very weak current. The Ni content varies between 50 and 80%.
• Ferritic stainless steel. Grades 430 or 434 are typically used. It is used for applications that work in oxidizing environments. Its magnetic properties are limited.
• SMC microencapsulated materials. They are used in high frequency applications, from 400 Hz to 100 KHz, where laminated stack is typically used. They are based on an iron powder whose particles are coated with a thin electrical insulation layer that provides a very high resistivity, up to 2,200,000 μΩ·cm, and permeability stability versus the frequency (see following graph). The isotropy of SMC materials allows to design more compact and efficient components, reducing their weight up to 50% and saving copper from the coils, although it is necessary to redesign the part or consider the SMC material from the beginning of the project to make it competitive against the laminated sheet.