MIM-Fe08Ni Soft Magnetic Alloy
MIM-Fe08Ni is an iron-nickel soft magnetic alloy optimized for Metal Injection Molding. With 8% nickel content, this material delivers high magnetic permeability, low coercivity, and stable magnetic properties across a wide frequency range. MIM-Fe08Ni enables the production of complex magnetic components — such as sensor cores, solenoid plungers, and motor laminations — that would be impossible to manufacture efficiently using conventional powder metallurgy or machining.
At Emitech, we manufacture precision MIM-Fe08Ni parts with near-full density and isotropic magnetic properties. Our controlled sintering atmosphere prevents oxidation and ensures consistent permeability from lot to lot, meeting the demanding requirements of automotive sensors, industrial automation, and consumer electronics applications.
Material Characteristics
MIM-Fe08Ni combines the design flexibility of MIM with soft-magnetic performance suitable for low-to-medium permeability applications. Key characteristics include:
- High permeability — Initial relative permeability exceeds 2000, ideal for low-field applications
- Low coercivity — Below 80 A/m, enabling rapid magnetization and demagnetization
- High saturation flux density — Bs exceeds 1.5 T, maximizing energy conversion efficiency
- Low core loss — Fine grain structure minimizes hysteresis and eddy current losses
- Thermal stability — Magnetic properties stable from -40°C to 200°C
- Isotropic properties — Uniform magnetic response in all directions
Chemical Composition
The typical chemical composition of MIM-Fe08Ni powder:
| Element | Weight % (typical) |
|---|---|
| Iron (Fe) | Balance |
| Nickel (Ni) | 7.5 - 8.5 |
| Molybdenum (Mo) | ≤ 0.5 |
| Carbon (C) | ≤ 0.02 |
| Manganese (Mn) | ≤ 0.5 |
| Silicon (Si) | ≤ 0.5 |
| Phosphorus (P) | ≤ 0.02 |
| Sulfur (S) | ≤ 0.02 |
Magnetic Properties
The magnetic performance of MIM-Fe08Ni is characterized by the following parameters:
| Property | Value (Typical) |
|---|---|
| Initial Permeability (μi) | ≥ 2,000 |
| Maximum Permeability (μmax) | ≥ 15,000 |
| Coercivity (Hc) | ≤ 80 A/m |
| Saturation Flux Density (Bs) | ≥ 1.55 T |
| Remanence (Br) | ≤ 0.8 T |
| Curie Temperature (Tc) | ≈ 750°C |
| Electrical Resistivity | ≈ 12-15 μΩ·cm |
| Density (sintered) | ≥ 7.7 g/cm³ |
MIM Soft Magnetic Alloy Comparison
Emitech offers three iron-nickel soft magnetic alloys for MIM, each optimized for different magnetic and cost requirements:
| Property | MIM-Fe02Ni | MIM-Fe04Ni | MIM-Fe08Ni |
|---|---|---|---|
| Nickel Content | 1.5 - 2.5% | 3.5 - 4.5% | 7.5 - 8.5% |
| Initial Permeability (μi) | 400 - 600 | 800 - 1,200 | ≥ 2,000 |
| Coercivity (Hc) | 150 - 250 A/m | 100 - 150 A/m | ≤ 80 A/m |
| Saturation Flux Density | ≥ 1.7 T | ≥ 1.6 T | ≥ 1.55 T |
| Relative Cost | Lowest | Moderate | Highest |
| Best For | High-flux, cost-sensitive | Balanced performance | High-permeability sensors |
Typical Applications
MIM-Fe08Ni is specifically chosen for applications requiring rapid magnetic response and high sensitivity:
- Position sensors — Proximity sensor cores, Hall effect sensor housings, and magnetic encoders
- Solenoid valves — High-response plungers and armatures for fuel injection and hydraulic systems
- Brushless motors — Stator and rotor components for small DC motors and stepper motors
- Current transformers — Toroidal cores for energy metering and power monitoring
- Magnetic shields — Shielding enclosures for sensitive electronic circuits
- Relays and contactors — Magnetic yokes and pole pieces for electromechanical switches
Why Choose Emitech for MIM-Fe08Ni Parts?
- Controlled atmosphere sintering — Hydrogen/nitrogen atmosphere prevents oxidation and maintains permeability
- Magnetic testing — In-house B-H curve analysis and permeability verification
- Complex geometries — Internal channels, thin walls, and asymmetric shapes for optimized magnetic circuits
- Consistent properties — Statistical process control ensures lot-to-lot repeatability
- Insulation coating — Optional phosphate or oxide insulation layers for laminated stacks
- Custom alloys — Alloy adjustments available for specific permeability or resistivity requirements
Frequently Asked Questions
Q: How does MIM-Fe08Ni compare to silicon steel for motor laminations?
A: Silicon steel (3% Si-Fe) offers lower core loss at high frequencies and is the standard for large motor laminations. However, silicon steel is brittle and cannot be formed into complex 3D shapes by MIM. MIM-Fe08Ni excels in small, complex magnetic components where permeability and formability are more important than minimizing core loss. For high-frequency applications above 10 kHz, consider our Fe-based amorphous or nanocrystalline options.
Q: What is the maximum operating frequency for MIM-Fe08Ni?
A: MIM-Fe08Ni performs well up to approximately 100 kHz in uncut solid cores. Beyond this frequency, eddy current losses increase significantly. For higher frequencies, we recommend either stacking insulated laminations or using ferrite materials. Our engineering team can calculate core loss versus frequency for your specific application.
Q: Can MIM-Fe08Ni be heat treated to improve magnetic properties?
A: Yes. A hydrogen anneal at 1100-1200°C reduces residual stresses and coercivity while increasing permeability. This treatment is typically performed after sintering as an integral part of our process. Additional magnetic annealing in a controlled magnetic field can further optimize properties for specific orientations.
Q: How does MIM-Fe08Ni handle corrosion compared to stainless steel?
A: MIM-Fe08Ni has moderate corrosion resistance due to its nickel content but is not comparable to stainless steels. For applications requiring both magnetic properties and corrosion resistance, we recommend protective coatings such as electroless nickel plating, parylene coating, or epoxy encapsulation. Contact us to discuss the best protection strategy for your environment.
Q: What is the typical insulation coating for laminated MIM-Fe08Ni stacks?
A: We offer several insulation options for stacked assemblies: inorganic phosphate coatings (0.5-2 μm), organic resin coatings, and natural oxide layers. Phosphate coatings provide the best combination of insulation resistance, temperature stability up to 500°C, and minimal impact on magnetic properties. Coating thickness is controlled to ensure interlaminar resistance exceeds 100 MΩ per layer.
Q: How does MIM-Fe08Ni compare to higher-nickel soft-magnetic alloys?
A: MIM-Fe08Ni is positioned between low-carbon steel/Fe-2Ni and high-permeability Permalloy grades. It offers good permeability and low coercivity for many sensor, solenoid, and motor-core applications while enabling complex net-shape parts. For applications requiring Permalloy-level permeability, higher-nickel grades such as Fe-50Ni or Fe-80Ni should be selected.
Q: What tolerances can be held on MIM-Fe08Ni magnetic components?
A: Typical as-sintered tolerances are ±0.3% to ±0.5% of nominal dimension. For critical magnetic air gaps or pole face dimensions, we provide precision grinding to achieve ±0.01 mm flatness and parallelism. Magnetic gap tolerances down to ±0.02 mm are achievable through a combination of MIM precision and selective grinding.
Q: Is MIM-Fe08Ni suitable for high-temperature applications?
A: MIM-Fe08Ni maintains stable magnetic properties up to approximately 200°C continuous operation. The Curie temperature is around 750°C, but permeability begins to degrade above 200°C due to thermal agitation of magnetic domains. For applications above 200°C, we recommend MIM-Fe02Ni (higher Curie temperature) or cobalt-iron alloys for extreme temperatures up to 500°C.
Request a Quote for MIM-Fe08Ni Parts
Developing a magnetic sensor, solenoid, or motor component? Our magnetic materials engineers will analyze your flux density, permeability, and operating frequency requirements to specify the optimal alloy and geometry. Submit your drawing or 3D model for a comprehensive quotation.
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