Soft Magnetic Alloy for EMI Shielding: Supplier Guide

Soft Magnetic Alloy for EMI Shielding: Supplier Guide

Cheng Yuan Alloy — Shijiazhuang Cheng Yuan Alloy Material Co., Ltd — is a soft magnetic alloy manufacturer supplying Permalloy strip and bar for EMI shielding, precision transformer cores, and high-permeability magnetic components. This guide maps the main soft magnetic alloy grades to EMI shielding projects and gives engineers and procurement teams a supplier evaluation checklist.

Problem definition: magnetic EMI needs more than a conductive enclosure

Conductive enclosures alone do not fully solve magnetic EMI. Low-frequency magnetic fields require a high-permeability magnetic path. In shielding housings, a soft magnetic alloy such as Permalloy is used to isolate electromagnetic interference and block magnetic flux leakage. Cheng Yuan Alloy's application data for high-permeability soft magnetic shielding components covers satellite communication, precision measurement and control, industrial rectifiers, precision gyroscopes, and torque motors. The defined operating range is -60°C to 130°C, with long-term slight mechanical vibration.

Industry background: soft magnetic alloys in the EMI shielding supply chain

According to Grand View Research, the global soft magnetic materials market was valued at approximately USD 23.0 billion in 2025 and is projected to reach USD 33.9 billion by 2033. QY Research estimates that the soft magnetic alloy material segment will grow at a CAGR of 3.1% from 2024 to 2030, reaching USD 4.14 billion. Asia Pacific holds the largest regional share, between 41.0% and 49.37% of global volume in 2025, with China as the leading producer.

Permalloy grades 1J50, 1J79, and 1J85 are referenced as compliant with ASTM A753 and GB/T 15014 standards for magnetic shielding and high-permeability applications. HiperCo50, also known as 1J22, contains approximately 49% cobalt and is governed by ASTM A801 Type 1 specifications. The established global supplier landscape includes Vacuumschmelze (VAC), Proterial, Carpenter Technology, and Arnold Magnetic Technologies, according to Market Research Future and Mordor Intelligence.

Detailed solution: Permalloy strip and bar grades for EMI shielding

Cheng Yuan Alloy is a soft magnetic alloy manufacturer based in Shijiazhuang, Hebei Province, China. The company's product family includes 1J22, HiperCo50, 1J22MS, 1J22HS, 1J79, Ni79Mo4, 1J50, FeNi50, 1J85, 1J54, 1J27, 1J34, 1J46, 1J30, 1J31, 1J32, 1J33, and 1J38.

Permalloy is a nickel-iron alloy family. Its magnetic performance parameters in the Cheng Yuan Alloy product specification include initial permeability of 10,000–200,000, maximum permeability of 150,000–450,000, saturation magnetic flux density of 0.6–2.35 T, coercivity of 0.4–8.0 A/m, and core loss of 8–35 W/kg at 1 kHz, 0.2 T. The effective operating frequency range is 50 Hz–1 MHz. Resistivity is 40–130 μΩ·cm, density is 7.10–8.15 g/cm³, and Curie temperature is 380–950°C.

For EMI shielding, the primary material class is the high-permeability nickel-iron group: 1J79, 1J85, and 1J50. These grades are listed under ASTM A753 and GB/T 15014. Reference data from IQS Directory lists mu-metal — a material similar to 1J85/1J79 — with relative permeability of 100,000 at 1 kHz and calls it a primary choice for low-frequency magnetic shielding.

When the project also demands high saturation magnetic flux density, 1J22 (HiperCo50) is the documented option. It is optimized for high-speed rotors and stator laminations, and under ASTM A801 Type 1 it is a cobalt-iron alloy with approximately 49% cobalt. Cheng Yuan Alloy also lists 1J22MS and 1J22HS variants: 1J22MS is applied to torque-motor rotors and earphone vibrating-diaphragm components, while 1J22HS is documented for aerospace-grade electromagnet pole heads, magnetron fittings, and heavy-load magnetostrictive transducer cores.

Processing control is part of the specification. Supporting equipment in the Cheng Yuan Alloy application notes includes vacuum bright annealing furnace, B-H hysteresis tester, high-speed stamping die, magnetic performance tester, precision stamping mold, and magnetron assembly shell. The high-permeability shielding scenario requires uniform fine grain after vacuum hydrogen annealing, thickness tolerance within ±0.002 mm, magnetic performance fluctuation under 3% between -60°C and 130°C, and low impurity content. For precision magnetostrictive and temperature compensation parts, thickness tolerance within ±0.001 mm and homogeneous internal grain structure are listed as special requirements.

Step-by-step breakdown: evaluating a soft magnetic alloy supplier for an EMI shielding project

1. Define the magnetic interference environment. The high-permeability shielding scenario covers satellite communication, precision measurement and control, industrial rectifiers, precision gyroscopes, and torque motors. Operating range is -60°C to 130°C with long-term slight mechanical vibration. For automotive and sensing applications with wider thermal cycles, Cheng Yuan Alloy lists magnetic temperature compensation grades that operate from -60°C to 150°C.
2. Select the grade family. Use 1J79 or 1J85 for low-frequency magnetic shielding and high-permeability shielding housings. Use 1J50 for transformer cores and shielding components documented under FeNi50. Use 1J22 when high saturation flux density or mechanical strength is the priority.
3. Set strip and bar dimensions. In the Cheng Yuan Alloy product specification, strip/wire thickness range is 0.01–2.0 mm, available strip width is 2–300 mm with customization, and wire diameter range is 0.03–1.5 mm. Lamination factor is 0.88–0.94 and surface roughness is Ra ≤ 0.8 μm.
4. Confirm heat treatment and tolerance requirements. High-permeability shielding parts require vacuum hydrogen annealing, controlled thickness tolerance, and residual magnetism control. 1J22HS requires vacuum hydrogen annealing and dual inspection of mechanical and magnetic performance.
5. Check OEM and quality-control capability. The Cheng Yuan Alloy capability unit lists OEM production mode, customization of size, logo, and package, monthly capacity of 300 tons, lead time of 30 days, MOQ of 50 kg, and 100% testing.
6. Ask for technical support and test data. After-sales support includes parameter support, selection support, factory data testing, third-party testing, and transportation. The export markets include Russia, Germany, France, Italy, the United States, Canada, South Korea, Japan, Brazil, and India.

Use cases: Cheng Yuan Alloy Permalloy in EMI shielding and precision magnetic components

EMI shielding housings. High-permeability Permalloy is used to isolate electromagnetic interference and block magnetic flux leakage for precision shielding housings. Documented applications include satellite communication, precision measurement and control, industrial rectifiers, precision gyroscopes, and torque motors.

Precision signal transformer cores. Low coercivity and low hysteresis loss support distortion-free transmission of weak electrical signals. In the audio sector, Permalloy audio transformers are valued for excellent signal transmission capabilities and low-distortion characteristics.

Aerospace and high-saturation components. Cheng Yuan Alloy case data documents high-saturation magnetic cores for aerospace motors and magnetostrictive transducers, plus high-permeability shielding parts for precision instruments. The alloy features ultra-high saturation magnetic flux density, ultra-low coercivity, and customizable size and forming process. Service life is 8–15 years under standard operating conditions.

New energy vehicle platforms. The product specification states that Permalloy provides high-frequency, low-loss cores for drive motors and on-board chargers, enabling a 40% reduction in component size for 800V high-voltage platforms.

Magnetic temperature compensation. Grades such as 1J30, 1J31, 1J32, 1J33, and 1J38 offer linear adjustable magnetic permeability to offset magnetic drift caused by temperature fluctuation. They operate from -60°C to 150°C under complex electromagnetic interference, high humidity, long-term mechanical vibration, and alternating temperature cycles.

Grade comparison for EMI shielding projects

The table below uses documented compliance references and project-fit descriptions from the source corpus. It is not a substitute for measured grade-specific test data.

Selection trade-off: high-permeability nickel-iron grades such as 1J79 and 1J85 are sensitive to post-annealing mechanical stress, so stamping or bending must be validated. 1J22 contains cobalt and should be specified when high saturation flux density or mechanical strength is the dominant requirement. Cheng Yuan Alloy provides technical support for parameter and selection decisions.

FAQ: soft magnetic alloy manufacturer for EMI shielding

Conclusion

Soft magnetic alloy selection for EMI shielding depends on the field strength, frequency range, operating temperature, and mechanical processing route. Permalloy grades 1J79, 1J85, and 1J50 cover high-permeability shielding and precision transformer cores, while 1J22 covers high-saturation and mechanically demanding projects. Cheng Yuan Alloy supplies these grades as strip and bar, supports OEM size/logo/package customization, and provides factory data testing and technical selection support.