Sintered soft magnetic products
Applications for Sintered Soft Magnetic products are typically based on direct current with a frequency of less than 50 Hertz. PM’s excellent material properties combined with net or near net shape capability delivers a competitive solution for many electro-mechanical system challenges.
Sintered Soft Magnetic materials can be modified to independently vary the saturation induction or the coercive force – as compared to wrought materials where only the coercive force can be changed. This unique capability can be leveraged to deliver a unique solution for certain applications.
Figure 1. Production Process Sintered Soft Magnetics
1) Raw Material
Pure iron powder is the base material for most sintered soft magnetic products, however some applications may require alloy additions of Phosphorus, Silicon, or Nickel.
2) Pressing
By using special presses with multi-level technology is it possible to manufacture products in the density range >7.4 g/cm³. This technology helps us to achieve a homogeneous density distribution which has a positive effect on the magnetic properties.
3) Sintering
The performance of Soft Magnetic products can be improved if sintering temperatures are higher than that used for the conventional process, and also if the atmosphere is 100% hydrogen.
4) Secondary Operations
Secondary operations such as sizing (ideally followed by annealing to relieve residual stresses), deburring, machining, etc., can be applied after sintering if required.
Figure 2: Microstructure - sintered material (A: particle; B: pore; C: grain boundary)
Application:
Direct Current
Low frequency power <50 Hz
Features:
- High saturation induction
- Low coercitivity
- High permeability
- Low residual magnetism