Powder Core Materials Patents: Top Companies & Filing Trends 2026
- Concentrated at the top. The five leading assignees account for 224 of 454 records in scope, 49.3% of the field, with the leader alone holding 78.
- Filing has cooled from its 2018 peak. Annual filings ran from 37 in 2018 down to 5 in 2024, a -67% drop between 2021 and 2024 for the assignees tracked.
- Powder metallurgy claims dominate the chemistry. B22F powder-metallurgy classifications sit on 69.8% of records, alongside H01F on 94.1% and C22C alloy claims on 34.4%.
Filing growth compares 2021 (15 records) with 2024 (5) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 454 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape maps 454 published records at the intersection of powder magnetic core composition and the performance metrics that determine inductor viability: permeability, DC bias behaviour, high-frequency loss, particle size distribution, binder content, saturation flux density and temperature rise. The scope spans iron-silicon-aluminium and related soft-magnetic powder systems used in compressed powder cores for power inductors, not ferrite or laminated cores generally.
Filing activity is tracked from 2015 through the 2026-07-31 cut-off, with the caveat that publication typically lags filing by around 18 months, so the last one to two years of the trend will fill in further as more applications publish.
Filing trend and technology composition
The two views below cover the same 454 records: one shows when they were filed, the other shows what technical classes they carry.
A 2018 peak followed by a multi-year pullback
Filings rose to a peak of 37 in 2018, then eased. Among the tracked assignees, annual output fell from 15 in 2021 to 5 in 2024, a -67% change over that span. 2025 and 2026 figures are still incomplete because of publication lag and should not be read as a continued decline.
Powder metallurgy and alloy chemistry drive the classification mix
H01F (magnets, inductors and transformers) appears on 94.1% of the 454 records, confirming the search scope, while B22F (powder metallurgy) at 69.8% and C22C (alloys) at 34.4% show that most claims are anchored in how the powder is made and alloyed rather than in device-level integration. Smaller classes — H02K, B32B, C21D, B05D and C03C — each sit under 4% and point to narrower, less-crowded application angles such as motor cores, laminated structures, heat treatment and coating.
Shares are the percentage of the 454 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Powder Core Materials for Power Inductors with Eureka
This page is one run against one query. Ask Eureka your own question about powder core materials for power inductors and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
Soft magnetic powder and method for producing powder magnetic core (US20210046549A1)
Provided is a soft magnetic powder capable of forming a powder magnetic core having a high magnetic permeability with a decreased oxygen content even when the particle size is small. There is provided a soft magnetic powder including Fe alloy containing Si which is a soft magnetic powder containing 0.1% to 15 mass % of Si, and having a product of D50 multiplied by [O] (D50×[O]) being 3.0 [μm·mass %] or less, wherein D50 represents a volume-based cumulative 50% particle size [μm] of the soft magnetic powder as measured by a laser diffraction particle size distribution analyzer, and [O] represents an oxygen content [mass %].Filed by DOWA Electronics Materials, published 2021-02-18. The claim ties a specific particle-size-times-oxygen-content product to achievable permeability, a concrete formula that later filers working on fine-particle powders need to design around.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | JP2005307291A | Amorphous soft-magnetic alloy powder, and powder magnetic core and electromagnetic wave absorber using it | 102 |
| 2 | US5651841A | Powder magnetic core | 89 |
| 3 | US5160447A | Compressed powder magnetic core and method for fabricating same | 66 |
| 4 | US20120082844A1 | Powder magnetic core | 60 |
| 5 | US20040126609A1 | Metal powder and powder magnetic core using the same | 56 |
| 6 | JP2009054615A | Powder magnetic core, and manufacturing method thereof | 50 |
| 7 | US20110095628A1 | Axial gap motor, compressor, motor system, and power generator | 45 |
| 8 | US20130056674A1 | Powder magnetic core and process for production thereof | 44 |
| 9 | US20080044679A1 | Soft Magnetic Material, Powder Magnetic Core, Method for Manufacturing Soft Magnetic Material, and Method for… | 37 |
| 10 | US6903641B2 | Dust core and method for producing the same | 37 |
Citation counts reflect influence within the searched corpus and skew toward older filings; treat them as a signal of historical importance rather than current filing activity.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns matter more than the raw counts: who has already claimed the core chemistry, where filing has slowed rather than accelerated, and which classes are thin enough to still be worth a look.
The core chemistry is well-claimed by a small group
Five assignees hold 224 of the 454 records in scope, with the leader alone at 78. A newcomer filing on basic Fe-Si-Al powder composition or standard compaction methods is filing into dense prior art held by a handful of established players.
Filing has pulled back from its 2018 peak
Annual filings peaked at 37 in 2018 and tracked assignees show a -67% drop from 15 filings in 2021 to 5 in 2024. Recent-year figures for individual leaders show 0 filings in the latest tracked year, but publication lag means 2025-2026 data is still incomplete.
Powder processing, not device integration, is the crowded layer
B22F and C22C classes together show that most claims sit at the material and process level — particle formation, alloying, compaction — rather than at motor or device integration, where H02K sits at just 3.7% of records.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to powder core materials for power inductors, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranking covers 70 companies returned by the data endpoint, not a curated top-50 or top-100 list. A leader-plus-long-tail pattern is visible: a handful of assignees dominate the top of the ranking, then filing counts drop off quickly.
A single leader holds the largest share
The top-ranked assignee holds 78 of the 454 records in scope, well ahead of fifth place at 30 and tenth place at 14 — a steep drop-off that marks a genuine leader rather than a crowded tie at the top.
Co-assignee filing is limited but concentrated
Only 10 co-assignee pairs appear across the dataset. The strongest pair, an automaker filing jointly with its own research institute, accounts for 17 co-filed records — suggesting most collaboration happens inside a single corporate group rather than across company lines.
US, Europe and Japan lead receiving offices
The United States receives the most filings at 156, followed by the EPO at 97 and Japan at 88. China sits at 51 and WIPO/PCT filings at 14, with Canada at 12 — a filing footprint weighted toward the US, Europe and Japan rather than China-first strategies.
| Assignee | Recent year | YoY |
|---|---|---|
| Seiko Epson Corporation | 0 | -100% |
| Proterial, Ltd. | 0 | — |
| Sumitomo Electric Industries, Ltd. | 0 | — |
| TDK Corporation | 0 | — |
| Toyota Motor Corporation | 0 | — |
| Tokin Corporation | 0 | -100% |
| NTN Corporation | 0 | — |
| Toyota Central R&D Labs, Inc. | 0 | — |
Where to take this next
The data points to specific next steps depending on whether the goal is freedom-to-operate, competitive tracking, or scouting open claim space.
Check freedom-to-operate against the concentrated leaders
With 49.3% of records held by five assignees, any filing near core powder composition or compaction method should be checked against their specific claim scope, not just the general prior art.
Explore assignee portfolios in Eureka →Watch for the next filing wave once lag clears
The 2021-2024 pullback is real, but 2025-2026 figures are incomplete due to publication lag. Re-check filing trends in 12-18 months before concluding the field has permanently slowed.
Set up trend tracking in Eureka →Scope claims toward under-represented classes
Motor integration, laminated structures and coating processes each sit under 4% of records, well below the core chemistry classes — a possible entry point for narrower, less-contested claims.
Run a white-space search in Eureka →Common questions about this landscape
The dataset ranks 70 assignees across 454 records, with the leading company holding 78 records on its own. The top five assignees combined account for 224 records, or 49.3% of all records in scope, and the top ten reach 331 records, 72.9% of the field. This concentration means a small group of established manufacturers controls most of the documented claim space around core powder chemistry and processing.
Filing peaked at 37 records in 2018 and has since pulled back; among tracked assignees, annual filings fell from 15 in 2021 to 5 in 2024, a -67% change. That said, patent publication typically lags filing by about 18 months, so the 2025 and 2026 figures in any trend chart are still incomplete and should not be read as confirmation of a continued decline. A clearer read on the most recent years will only be possible once those cohorts finish publishing.
H01F (magnets, inductors and transformers) appears on 94.1% of the 454 records, which reflects the search scope itself, while B22F (powder metallurgy) at 69.8% and C22C (alloys) at 34.4% show where the substantive claim density sits: powder formation, compaction and alloy composition. Classes tied to device integration or secondary processing — H02K motor cores, B32B laminates, C21D heat treatment, B05D coatings and C03C glass/enamel systems — each sit under 4% of records, indicating comparatively open ground there.
This DOWA Electronics Materials filing, published 2021-02-18, claims a soft magnetic Fe-Si alloy powder defined by a specific relationship between particle size and oxygen content — the product of D50 (median particle size) and oxygen content capped at 3.0 micrometre-mass percent. That formula is aimed at achieving high permeability even with fine particles, which is a common trade-off in powder core design. Anyone developing fine-particle soft magnetic powders for high-permeability cores should check their oxygen control and particle size specifications against this claim boundary.
The classification data points to several under-claimed branches relative to the dominant powder metallurgy and alloy classes: motor and generator core integration, laminated powder-core structures, post-compaction heat treatment schedules, insulative coating processes, and glass or enamel binder systems each represent under 4% of the 454 records. These are not guarantees of novelty, but they carry markedly less claim density than core composition and compaction, making them reasonable areas to scope a freedom-to-operate or novelty search before committing to a filing strategy centred on basic powder chemistry.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.