Soft Magnetic Composite Coatings Patents: Top Companies & Trends 2026
- 29.3% concentration at the top. The five leading assignees together hold 701 of 2,394 records in scope, but the next tier thins quickly — tenth place sits at just 22 records.
- Filing has cooled from its 2020 peak. Annual filings hit 139 in 2020; by the last complete year, 2024, they had settled to 85, down 14% from 2021's 99.
- Coating claims sit inside a metallurgy-heavy field. H01F magnetics claims cover 42.1% of records, while the coating-specific C23C and C09D classes each account for under a fifth — a gap worth examining.
Filing growth compares 2021 (99 records) with 2024 (85) — 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 2,394 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Soft magnetic composite (SMC) insulation coatings sit at the intersection of powder metallurgy and surface chemistry: an insulating layer applied to iron-based powder particles so that, once compacted and annealed, the resulting core suppresses eddy current loss without sacrificing magnetic permeability. The patent activity mapped here spans 2,394 records filed or published between 2015 and mid-2026, drawn from claims referencing core loss, coating thickness, resistivity, compaction density and annealing temperature.
Because a single coating formulation can be claimed alongside a powder composition, a compaction process and a finished motor or inductor, records in this set commonly carry multiple IPC classes at once. That overlap is informative: it shows how tightly coating chemistry claims are bundled with the metallurgical and end-use claims around them, rather than standing alone.
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Filing trends and technology composition
Two views of the same 2,394-record set: how filing volume has moved year over year, and which IPC subclasses the claims fall under. Publication lags filing by roughly 18 months, so the last one to two years in the trend will keep filling in after this cut-off.
A 2020 peak, then a step down
Annual filings rose from 49 in 2017 to a peak of 139 in 2020, then eased to 99 in 2021 and 85 in 2024 — a 14% decline over that three-year span. Figures for 2025 and 2026 are still incomplete and should not be read as a continued slide.
Coating classes trail the magnetics core
H01F (magnets, inductors and transformers) appears in 42.1% of records, the largest single class. C23C (coating and surface deposition) and C21D (heat treatment of metals) each sit at 18.3%, with C22C (alloys) close behind at 17.6% — coating-specific claims are present but outnumbered by the magnetics and metallurgy classes that surround them.
Shares are the percentage of the 2,394 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Soft Magnetic Composite Insulation Coatings with Eureka
This page is one run against one query. Ask Eureka your own question about soft magnetic composite insulation coatings and every answer comes back with the patent numbers behind it.
Try EurekaKey patents shaping the field
US20080008897A1 — Magnetic powder, soft magnetic composite, and method of forming same
A magnetic powder comprising iron-based particles with a spherical or smoothed surface, coated with an insulator made of rare earth, alkaline metal or alkaline earth metal fluorides. The resulting soft magnetic composite suppresses eddy current loss across a wide frequency band and limits hysteresis loss from compressed residual distortion in the powder.Filed by Imagawa, Takao — published 2008-01-10.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5639989A | Shielded electronic component assembly and method for making the same | 703 |
| 2 | KR1020140015647A | Electrode assembly, manufacture thereof, and secondary batteries including same | 289 |
| 3 | US6284810B1 | Method and apparatus for microcellular polymer extrusion | 251 |
| 4 | US4119368A | Elastomer display device | 248 |
| 5 | JP1989037801A | Voltage nonlinear element | 245 |
| 6 | US6281450B1 | Substrate for mounting semiconductor chips | 207 |
| 7 | US6884377B1 | Method and apparatus for microcellular polymer extrusion | 156 |
| 8 | WO1998008667A2 | Method and apparatus for microcellular polymer extrusion | 127 |
| 9 | US20040159383A1 | Method for embedding a radio frequency antenna in a tire, and an antenna for embedding in a tire | 110 |
| 10 | US6191487B1 | Semiconductor and flip chip packages and method having a back-side connection | 108 |
Citation counts accumulate over time, so older filings dominate this table by construction — treat it as a map of influential prior art, not of current filing activity.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the data means for filing strategy
Three patterns stand out once the assignee ranking, IPC composition and filing trend are read together.
The top of the field is settled, the middle is not
The leader alone accounts for 263 records, and the top five combined hold 29.3% of all 2,394 records in scope. But the count falls off fast after that — tenth place holds only 22 — which means the mid-tier is a long tail of firms each with a handful of filings rather than a second cluster of major players.
Volume has stepped down from its 2020 high, not collapsed
Filings peaked at 139 in 2020, then settled to 99 in 2021 and 85 in 2024, a 14% decline over that span. That is a normalisation from an unusually active year rather than a sign the field is closing — 2025-2026 figures are still incomplete due to publication lag.
Coating chemistry is claimed inside magnetics, not around it
H01F covers 42.1% of records, well ahead of the coating-specific C23C and C09D classes at 18.3% and 9.9%. Most insulation-coating claims are bundled with finished-component claims — a filer targeting coating chemistry alone is competing in a comparatively less crowded slice of the same corpus.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to soft magnetic composite insulation coatings, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Sumitomo Electric Industries, Ltd. | Autonetworks Technologies, Ltd. | 19 |
| Sumitomo Electric Industries, Ltd. | Sumitomo Wiring Systems, Ltd. | 19 |
| Sumitomo Electric Industries, Ltd. | Toyota Motor Corporation | 8 |
| JFE Steel Corporation | Dai Nippon Toryo Co., Ltd. | 7 |
| Sumitomo Electric Industries, Ltd. | Toda Kogyo Corporation | 7 |
| Hoganas AB | SKARMAN BJORN | 6 |
| Nippon Steel Corporation | Nippon Steel Engineering & Machinery Design Co., Ltd. | 5 |
| Hoganas AB | YE ZHOU | 5 |
The strongest co-assignee pairs in this set link a components supplier with a harness or vehicle-systems partner, and with an automaker directly — evidence that coating and compaction know-how is often jointly filed rather than developed by a single lab.
Who is filing, and where the openings sit
The ranked leaders span steelmakers, powder metallurgy specialists and electrical component makers, but the concentration data shows real room outside that group.
One filer well ahead of the field
The leading assignee holds 263 records, more than double the fifth-place total of 65 — a gap that suggests a long-running, deliberately built portfolio rather than a recent surge.
Ranking thins out quickly past the top five
By tenth place the count has dropped to 22 records, roughly a third of fifth place. Firms entering this space now are competing against a shallow mid-tier, not a deeply defended one.
Recent activity has shifted among established names
Several long-standing steelmaking assignees show zero filings in the latest year, while at least one shows a small but complete swing upward — a reminder to check recent-year activity alongside cumulative totals before assuming a leader is still active.
| Assignee | Recent year | YoY |
|---|---|---|
| JFE Steel Corporation | 2 | +100% |
| Nippon Steel Corporation | 0 | -100% |
| Hoganas AB | 0 | — |
| Sumitomo Electric Industries, Ltd. | 0 | — |
| Baoshan Iron & Steel Co., Ltd. | 0 | — |
| Pohang Iron & Steel Co., Ltd. (POSCO) | 0 | -100% |
| Kawasaki Steel Corporation | 0 | — |
| General Electric Company | 0 | — |
Where to take this analysis
The figures above describe the shape of the field. Turning that into a filing or freedom-to-operate decision means going deeper on specific claims and specific competitors.
Check freedom-to-operate against the densest classes
H01F, C23C and C21D carry the most claims in this set. Any new coating or compaction process should be checked against active filings in those classes before drafting.
Run a freedom-to-operate checkTrack the leading assignee's recent filings
A 263-record portfolio built by one filer is worth monitoring for continuation activity and recent priority claims, not just its historical size.
Monitor assignee activityDraft around the under-claimed branches
The gate chips above point to coating chemistry and thickness-control sub-areas with lighter claim density than the H01F core — a plausible place to stake a first claim.
Explore white space with EurekaCommon questions on this landscape
One assignee leads clearly with 263 records in this dataset of 2,394, more than double the fifth-ranked firm's 65. The ranking of 100 companies then thins quickly, with tenth place holding just 22 records. This pattern — a dominant leader followed by a long tail — means new entrants are not up against a crowded top tier once past the first few names.
Filing volume rose to a peak of 139 in 2020, then declined to 99 in 2021 and 85 in 2024, a 14% drop over that span. That is best read as a correction from an unusually active year rather than an exit from the field, since figures for 2025 and 2026 are still incomplete due to the roughly 18-month lag between filing and publication. Judge momentum from 2024 and earlier, not from the two most recent years shown in any chart.
H01F, covering magnets, inductors and transformers, appears in 42.1% of the 2,394 records in scope, the single largest class. Coating-specific classes C23C and C21D each sit at 18.3%, with C22C alloys close behind at 17.6%. This means most insulation-coating claims are filed alongside finished-component or metallurgical claims rather than as standalone coating-chemistry patents.
This filing claims a magnetic powder made of iron-based particles with a spherical or smoothed surface, coated with an insulator built from rare earth, alkaline metal or alkaline earth metal fluorides. The claimed benefit is suppression of eddy current loss across a wide frequency band and reduced hysteresis loss from compressed residual distortion in the powder. Anyone working with fluoride-based insulator layers on soft magnetic powder should read its claims closely, since it sits squarely in that sub-area.
The gap sits between the dense H01F magnetics core and the comparatively lighter coating-specific classes C23C and C09D, which cover 18.3% and 9.9% of records respectively. Sub-areas such as post-anneal resistivity retention and coating thickness control at high compaction density show fewer claims than the core magnetics and alloy classes around them. A first claim there would need to tie a specific coating chemistry or process step to a measurable resistivity or loss outcome rather than claiming the finished component broadly.
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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.