Mu-ferro/mu-metal foil
Mu-ferro(mu-metal or Permalloy) foil and tape, is a specialized material designed for effective low-frequency (LF) magnetic field shielding. It combines excellent soft magnetic properties with unusual mechanical hardness and flexibility. This means that tight bends can be realised with only very slight impairment of permeability. The fine strip thickness and comparatively low electrical conductivity permit effective shielding even of higher-frequency fields.
Key Features
- High permeability
- Easy to bend or fold
- Can be cut with scissors
- Good corrosion resistance in a normal environment
- Bending, folding, cutting does not cause major loss of attenuation
Custom Manufacturing
Custom Mu-ferro/mu-metal foil
Mu-ferro foil and tape can be customized to meet specific application requirements. Customization options include:
- Width and Length: Specify the width up to 150 mm and length up to 100 meters. Custom widths and lengths can be produced upon request to suit particular applications.
- Thickness: Depending on the shielding needs, different thicknesses such as 0.005~0.05mm(tolerance within ±5%) can be produced.
Product Specs
Material Properties
Mu-ferro foil works well for shielding low-frequency magnetic fields. Due to the low electrical resistance it shields both low-frequency electric fields (LF) and high-frequency fields (HF). Comparable with Mu-Metal specifications.
| Properties | Item | Data | Remarks |
|---|---|---|---|
| Magnetic | Saturation polarization | 0.74 T | 20°C |
| Saturation magnetostriction | ca. 1 ppm | ||
| Curie temperature | 700°F (370°C) | ||
| AC Magnetic | Initial permeability(60Hz) at B=40G [μ(40G)] | 100,000 | |
| μ at H= 4mA/cm [μ4] | 250,000 | ||
| Max. permeability [μmax] | 350,000 | ||
| Coercivity [Hc] | 20 mOe (15 mA/cm) | ||
| Saturation induction, Magnetic flux density [Bs] | 7,400 G (0.74 T) | ||
| Physical | Mass density | 8.7 g/cm3 | ESQ-612-38 |
| Electrical resistivity | 0.6 x 10-6 Ohm m | ||
| Coefficient of thermal expansion | 13.5 x 10-6 K-1 | 20~100°C | |
| Mechanical | Hardness (HV) | 270~420 | |
| Tensile strength | 1280 N/mm2 | > 0.2mm | |
| Yield strength | 1230 N/mm2 | ||
| Elongation | 1~3 % |
Classification Performance
Permalloys can be categorized by composition into four main types: 35%–40% Ni-Fe alloys, 45%–50% Ni-Fe alloys, 50%–65% Ni-Fe alloys, and 70%–81% Ni-Fe alloys. Each type can be processed to exhibit circular, rectangular, or flat hysteresis loops.
| Series | Nickel Content Range | Magnetic Characteristics | Microstructure & Texture | Typical Applications |
|---|---|---|---|---|
| HD-TF-MUF3540 | 35%–40% | Circular hysteresis loop; Magnetocrystalline anisotropy (K1) decreases with increasing Ni content; High electrical resistivity (e.g., ρ=60μΩ·cm at 40% Ni); Low core loss (0.05mm thick strip: 9 W/kg at 20kHz). | Fine-grained isotropic microstructure. | Square-wave transformers, DC-DC converters. |
| HD-TF-MUF4550 | 45%–50% | Highest saturation magnetization; K1>0; Achievable rectangular or circular hysteresis loops; High permeability, low coercivity. | Cube texture (for rectangular loop) or {210} texture / fine-grained isotropic structure (for circular loop). | Magnetic amplifiers, chokes, transformers, current transformers, ground fault circuit interrupters, micro-motors, relays. |
| HD-TF-MUF5065 | 50%–65% | Highest Curie temperature; K1≈0; Significant magnetic field heat treatment response. Low-temp treatment: rectangular loop, high DC permeability. High-temp treatment: improved dynamic characteristics. Transverse field treatment: flat loop (constant permeability). | {210} texture or fine-grained isotropic structure (after high-temp annealing). | Magnetic amplifiers, inductor components (constant-permeability alloys). |
| HD-TF-MUF7081 | 70%–81% | Highest Curie temperature; K1≈0; Significant magnetic field heat treatment response. Low-temp treatment: rectangular loop, high DC permeability. High-temp treatment: improved dynamic characteristics. Transverse field treatment: flat loop (constant permeability). | Cube texture (for rectangular loop); Controlled ordering to achieve K1≥0; Powder cores offer high resistance and stability. | Transformers, chokes, magnetic heads, magnetic shielding, magnetic modulators, powder cores for use at frequencies up to 300 Hz. |
Advantages
Mu-ferro foil works well for shielding low-frequency magnetic fields. Due to the low electrical resistance it shields both low-frequency electric fields (LF) and high-frequency fields (HF). Comparable with Mu-Metal specifications.
- Ease of Handling: Easily cut with scissors and applied to various surfaces.
- Effective Shielding: Provides up to 14 dB attenuation for LF magnetic fields and up to 100 dB at 1 GHz for HF fields when multiple layers are used.
- Versatile Applications: From cable shielding to large-area applications in military and aerospace industries.
Applications
Cover the magnetic field parts with permalloy foil, or protect the sensor from external magnetic fields by inserting the sensor control in the permalloy case.
- Electronic Devices: Prevents EMI in sensitive components and systems.
- Medical Equipment: Essential in MRI machines and other diagnostic devices to minimize external magnetic interference.
- Aerospace and Automotive: Used to shield critical avionics and automotive electronics.
- Research and Development: Utilized in scientific instruments like electron microscopes and magnetic sensors for accurate readings.
Dimensions Measurement Guide
Mu-ferro foil is a thin foil; its thickness is only 0.005~0.05mm, tolerance within ±5%. It combines excellent soft magnetic properties with unusual mechanical hardness and flexibility. This means that tight bends can be realised with only very slight impairment of permeability. The fine strip thickness and comparatively low electrical conductivity permit effective shielding even of higher-frequency fields. The roll can be ordered ordered up to 100 meter in length and a width up to 50 meter.
How to shield the magnetic field
It is most effective to enclose the source or affected parts of the magnetic field shield completely. Still, the shielding effect can be obtained even if only the specific part is covered or the cover type is installed, as shown above.
When you wrap a cylindrical shape or cover a rectangular housing, be careful not to make a gap between the joint and between the body and the lid.
RECENT PRODUCT
-
Abstract: This article delves into the production process of mu-metal foil, covering the entire workflow from raw material selection to finished product output.......
-
1. What is Mu-Ferro Foil?2. Composition of Mu-Ferro Foil3. Magnetic Properties of Mu-Ferro Foil4. Applications of Mu-Ferro Foil4.1 Electromagnetic Interference (EMI) Shielding4.2 Magnetic......
