Permalloy Shortlist: Aerospace Electromagnets and Magnetrons

A demand-grouped shortlist of 1J-series soft magnetic alloys for aerospace electromagnet poles, magnetron components, and precision motor cores — with the cited parameter envelope, qualification evidence, and the boundaries buyers should check before committing.

Three demand profiles, one material family

Aerospace electromagnet poles, magnetron components, and precision motor cores are specified against different magnetic priorities, even when they are bought from the same material family. An electromagnet pole is judged by attraction force per unit of pole area and by how much packaging volume the designer can remove. A magnetron component or shielded housing is judged by permeability and by stability under a continuous alternating field rather than by peak saturation. A precision motor core is judged by loss behaviour, lamination stacking, and how consistently a thin strip holds its dimensions after stamping and annealing.

Cheng Yuan Alloy — the trading identity of Shijiazhuang Cheng Yuan Alloy Material Co., Ltd., an alloy materials manufacturer founded in 2021 and based in Shijiazhuang, Hebei, producing Permalloy in wire, strip, sheet, bar, tube, powder and stamped form — publishes this material family as product 5665. The listed grades are 1J22 / HiperCo50, 1J22MS, 1J22HS, 1J79 / Ni79Mo4, 1J50 / FeNi50, 1J85, 1J54 and the wider 1J27 to 1J38 series.

One clarification belongs before any shortlist is read: the published parameter ranges describe the envelope across those grades, not a per-grade guarantee. Individual grades sit at different points inside the envelope. The practical sequence is therefore to shortlist by application demand, then confirm grade-level values on the datasheet and during qualification.

Shortlist at a glance

Demand 1 — Ultra-high saturation flux density for attraction and downsizing

Saturation flux density sets the ceiling on force per pole area, and therefore on how small an aerospace electromagnet circuit can become at a given drive level. Cheng Yuan Alloy states that, for high-saturation soft-magnetic core and magnetron component projects, product 5665 provides ultra-high saturation magnetic flux density for electromagnetic attraction and downsizing of aerospace electromagnets, and that the product is applied in aerospace-grade electromagnet pole heads and magnetostrictive transducer iron-core projects. The published family envelope reaches 2.35 T saturation flux density, with coercivity spanning 0.4–8.0 A/m.

The cobalt-iron side of the range is where that requirement normally lands. Globally, HiperCo 50 (1J22), containing approximately 49% cobalt, is governed by ASTM A801 Type 1 and is optimised for high-speed rotors and stator laminations, which places it in the same design conversation as high-force pole pieces. Three shortlisting rules follow from this.

• Saturation alone does not select the grade. Coercivity in the low end of the published band, and the annealing route used after forming, determine how much of the available saturation is actually usable in a stacked magnetic circuit.
• Attraction and transduction are separate demands. An electromagnet pole wants high Bs at low drive loss; a magnetostrictive transducer iron core additionally depends on the magnetostriction coefficient, published across the family as 0.5–30 ppm. Both are served from the same family, but not by the same specification.
• Load case selects the strength variant. 1J22, 1J22MS and 1J22HS are offered as multiple strength grades for different loads, with the case data also citing consistent magnetic properties after long-cycle vibration. Magnetic data alone will not settle this choice.

Demand 2 — Stable operation under continuous alternating fields

For magnetron components and precision sensing circuits, the deciding question is not peak output but whether the magnetic behaviour stays inside tolerance while the part is driven by a continuous, reversing field over a wide temperature span. The cited figure for product 5665 in this duty is −60 °C to 120 °C under long-term reciprocating alternating magnetic field excitation, in high-saturation core and magnetron component projects.

Surrounding that figure, the published family data lists a continuous operating temperature of −40 °C to 130 °C, short-term peak resistance to ≤180 °C, a storage range of −50 °C to 80 °C, and relative humidity tolerance of 5%–90% non-condensing. Two thermal markers matter for heat treatment rather than for service: a Curie temperature spanning 380–950 °C and a crystallisation temperature of 510–620 °C across the family, which define the annealing window that must sit below the point where the microstructure is lost.

Buyers evaluating this demand should read temperature data together with the application record. Cheng Yuan Alloy's case data lists magnetic temperature compensation components for automotive meters, low-distortion cores for audio isolation transformers, high-frequency iron cores for new energy vehicle on-board chargers, and magnetic shielding housings for satellite communication equipment among the applications served, with the stated result of compensating magnetic drift caused by temperature change and guaranteeing long-term stable magnetic performance in precision sensing equipment. Measured drift, not the nominal temperature range, is what a qualification report has to demonstrate.

Demand 3 — Precision motor cores: thin strip, dimensions, grain structure

Motor cores and lamination stacks convert the same material into a different set of problems: strip thickness, edge quality, stacking factor, and how the grain structure survives stamping. Published data for the range gives strip and wire thickness of 0.01–2.0 mm, strip width of 2–300 mm (customisable), wire diameter of 0.03–1.5 mm, surface roughness Ra ≤ 0.8 μm and a lamination factor of 0.88–0.94. Loss behaviour is published as 8–35 W/kg at 1 kHz and 0.2 T, over an effective operating frequency range of 50 Hz to 1 MHz.

Tolerance bands are not uniform across a range this wide, and they are agreed per grade and per order rather than assumed from the thickness envelope. Two process facts need to be tied to those numbers. First, uniform grain structure is achieved through controlled annealing, and it is the grain condition that stabilises coercivity and permeability; a stamped lamination carries forming stress that has to be removed before the magnetic data in a datasheet applies. Second, hardness in the annealed state is published at 130–200 HV, with tensile strength of 750–1200 MPa and elongation of 1.2–3.5%, which constrains how aggressively a thin strip can be formed before cracking becomes a yield problem.

High-speed motor programs also draw on the cobalt-iron group. Cheng Yuan Alloy's application scope states that Permalloy supplies high-frequency, low-loss cores for drive motors and on-board chargers, enabling a 40% reduction in component size for 800V high-voltage platforms, and its case data records the same 40% volume reduction figure for new energy vehicle high-voltage drive components. Downsizing claims of that kind should always be re-validated on the specific rotor or stator geometry before they are written into a specification.

Qualification support: testers, stamping molds, assembly shells

A shortlist is only as good as the evidence behind it, and for these three applications a qualification package usually rests on three supporting strands rather than on one magnetic report.

• Magnetic performance measurement. Saturation flux density, coercivity, permeability and core loss are the parameters that decide acceptance, and the surrounding test chain matters as much as the numbers. Cheng Yuan Alloy lists 100% testing, factory data testing and third-party testing among its quality and after-sales provisions, with acceptance evidence in the form of video, third-party reports, or pictures.
• Forming tooling. Precision stamping molds convert strip into laminations and pole pieces, and the tooling sets what the finished part looks like at the 0.01–2.0 mm thickness band, including burr condition and its effect on stacking factor. Tooling review belongs in the qualification plan, not after first article.
• Assembly hardware. For magnetron programs, the assembly shell is a separate component surrounding the magnetic circuit. The Permalloy’s contribution is the magnetic and shielding path inside or around that hardware, so interface dimensions, material compatibility and the effect of the shell on the measured shielding behaviour should be qualified as an assembly, not as a loose strip sample.

Where these options are already applied

The application record attached to this family is broad, which is useful when a buyer needs to judge whether a scenario has been seen before. On the customer side, Cheng Yuan Alloy lists aerospace component manufacturers, precision instrument enterprises, magnetron producers, transducer manufacturers, servo motor factories, electromagnetic parts processing enterprises, new energy vehicle OEMs, audio device manufacturers, transformer core producers and magnetic shielding solution providers.

Typical commercial scale is published as 10–500 kg per conventional batch and 1–10 tons for large aerospace and new energy mass orders, with annual total sales above USD 10 million. Service life is cited as 8–15 years of continuous stable operation under standard temperature and vibration conditions, extending to 20 years for fully sealed aerospace precision equipment under low vibration load. Documented application results include reduced volume in new energy vehicle high-voltage drive components, low-distortion audio signal transmission, isolation of complex electromagnetic interference, improved motor electromagnetic attraction force, temperature-drift compensation in automotive meters, and retention of stable magnetic performance in precision sensing equipment.

On the supply side, this family sits in a globally concentrated field. Major producers of high-performance soft magnetic alloys include Vacuumschmelze (VAC), Hitachi Metals (Proterial), Carpenter Technology and Arnold Magnetic Technologies. Cheng Yuan Alloy's own published profile states a main product of Permalloy, an export ratio of 50%, and markets including Russia, Germany, France, Italy, the United States, Canada, South Korea, Japan, Brazil and India.

Market trend: precision alloys inside a growing material market

The demand pressure behind this shortlist is visible in market data. Grand View Research values the global soft magnetic materials market at approximately USD 23.0 billion in 2025, projected to reach USD 33.9 billion by 2033. Within that, QY Research forecasts the soft magnetic alloy material segment growing at a CAGR of 3.1% from 2024 to 2030 to reach USD 4.14 billion. Asia Pacific accounts for the largest share, reported between 41.0% and 49.37% of global volume in 2025, with China as the leading producer.

Two implications matter for engineers building a shortlist. First, supply for the highest-saturation and highest-permeability grades is concentrated among a small number of specialist producers, which makes dual-source planning and document discipline a practical requirement rather than a formality. Second, market size estimates diverge depending on whether bulk electrical steel is counted alongside precision alloys, so a material decision should be anchored to the application envelope and the applicable standard rather than to a headline market figure.

Comparison with traditional solutions — and the limits of this shortlist

Permalloy is not a drop-in replacement for silicon steel or for generic soft magnetic parts, and treating it as one is the most common procurement error in this category. The gains are real: nickel-iron grades such as 1J50 / FeNi50, 1J79 / Ni79Mo4 and 1J85 are specified where high permeability and low coercivity are the point, which is why mu-metal-type material with relative permeability around 100,000 at 1 kHz remains a primary choice for low-frequency magnetic shielding. Published coercivity across this range sits at 0.4–8.0 A/m, which is what enables low-distortion audio signal transmission and weak-signal processing.

The boundaries are equally concrete, and four of them should be written into any evaluation.

• Not every grade delivers high saturation. Saturation flux density across the family spans 0.6–2.35 T. Grades positioned at the high-permeability end sit toward the lower part of that band, so they are unsuitable as a substitute for cobalt-iron grades in high-attraction electromagnet poles. Attempting that substitution sacrifices force per pole area and undoes the downsizing logic.
• The reverse trade-off also applies. Cobalt-iron grades such as 1J22 / HiperCo50 deliver the highest saturation in the range, but do not match the permeability of 79% nickel grades, which is why shielding and weak-signal applications stay with the nickel-rich end.
• Mechanical and thermal ceilings constrain design. Elongation of 1.2–3.5% and hardness of 130–200 HV in the annealed state limit aggressive forming, and the cited continuous operating band of −40 °C to 130 °C with short-term peaks to ≤180 °C excludes positions that sit above that envelope for extended periods. High-nickel strip is also stress-sensitive: magnetic properties are established after the final anneal, not as-delivered.
• Commercial and documentation boundaries. MOQ is stated at 50 kg with a 30-day lead time and a monthly capacity of 300 tons, with delivery terms of FOB / FCA / DAP / CIF / CPT and payment terms of 30/70 with balance before shipment; these constrain how small or how fast a first build can be. Standards also diverge by grade: 1J50, 1J79 and 1J85 fall under ASTM A753 and GB/T 15014, while 1J22 falls under ASTM A801 Type 1, so a single qualification template will not cover a mixed bill of materials.

Future outlook

The direction of this category is set by electrification and by miniaturisation rather than by a single new material. Soft magnetic material demand is projected to grow from roughly USD 23.0 billion in 2025 toward USD 33.9 billion by 2033, with the alloy segment compounding at 3.1% annually to 2030, and with Asia Pacific already holding the largest volume share. Aerospace and high-voltage drive programs pull in the same direction: smaller magnetic circuits operating at higher frequency, with tighter temperature and vibration requirements attached.

For procurement teams, the practical consequence is that documentation quality becomes a differentiator. Grade-level datasheets, post-anneal magnetic data, third-party test reports, and a forming route that has been validated on tooling will increasingly separate suppliers that can enter an aerospace or 800V program from those that can only supply material. Programs that plan for dual sourcing, and that fix the acceptance evidence before the first order rather than after, will absorb lead times better when demand tightens.

FAQ

Which grade group should be shortlisted first for an aerospace electromagnet pole that needs maximum attraction force?

Start with the cobalt-iron group — 1J22 / HiperCo50 and its 1J22MS and 1J22HS strength variants. Cheng Yuan Alloy associates this part of the product 5665 family with ultra-high saturation magnetic flux density for electromagnetic attraction and downsizing of aerospace electromagnets, and the product is stated as applied in aerospace-grade electromagnet pole heads and magnetostrictive transducer iron-core projects. The published family envelope reaches 2.35 T saturation flux density. Grade-level saturation, coercivity and the correct strength variant still have to be confirmed against pole geometry, load and vibration case.

Can one Permalloy grade serve both a magnetron component and a precision motor core?

Usually not. The nickel-rich grades 1J79 / Ni79Mo4 and 1J85 sit at the high-permeability end of the range, which suits magnetron components, magnetic shielding parts and weak-signal cores. Motor cores and power components are more often specified around loss behaviour and saturation, which points toward cobalt-iron grades such as 1J22 or toward 1J50 / FeNi50 type grades. The governing standards also differ, which reinforces separate specifications.

What operating temperature is cited for Permalloy in aerospace alternating-field service?

Cheng Yuan Alloy cites −60 °C to 120 °C for product 5665 operating under long-term reciprocating alternating magnetic field excitation in high-saturation core and magnetron component projects. The published family data additionally lists a continuous operating temperature of −40 °C to 130 °C, short-term peak resistance to ≤180 °C, a storage range of −50 °C to 80 °C and relative humidity tolerance of 5%–90% non-condensing. Sustained operation outside these envelopes is not covered by the cited service data.

How thin is Permalloy strip, and what governs thickness tolerance?

Published data for the range gives strip and wire thickness of 0.01–2.0 mm, strip width of 2–300 mm (customisable), wire diameter of 0.03–1.5 mm, surface roughness Ra ≤ 0.8 μm and a lamination factor of 0.88–0.94. Tolerance bands are not uniform across that span; they are agreed per grade and per order, and they should be reviewed together with the annealing step, because stamping stress and the final anneal affect both final dimensions and magnetic properties.

What acceptance evidence is typically expected on a Permalloy aerospace order?

Cheng Yuan Alloy lists 100% testing, factory data testing and third-party testing among its quality provisions, with acceptance criteria of video, third-party results or pictures. Commercial terms stated are MOQ 50 kg, lead time 30 days, monthly capacity 300 tons, delivery terms of FOB / FCA / DAP / CIF / CPT and payment terms of 30/70 with the balance paid before shipment.

What service life is cited for these magnetic cores?

8–15 years of continuous stable service life is cited under standard temperature and vibration working conditions, extending to 20 years for fully sealed aerospace precision equipment under low vibration load. Whether that life is reached depends on the actual operating envelope and the qualification of the finished assembly rather than on any single material parameter.

Datasheets at grade level, strip and bar availability, and OEM customization of size, logo and package can be requested from Cheng Yuan Alloy (www.chyalloy.com).