Ferrite Magnet Patents: Top Companies & Filing Trends 2026
- Five companies hold 72.2% of the field. 254 of the 352 records in scope sit with the top five assignees, leaving a long tail of single- and few-filing entrants.
- Filing has plateaued, not grown. 2021 to 2024 shows 0% net change (2 to 2 filings), with 2022 as the peak year at 8 — this is a mature, steady-state field rather than a growing one.
- H01F dominates, but C22C alloy claims run close behind. 91.8% of records touch H01F magnet classification, while 42.0% also claim alloy composition under C22C, showing most filings bridge magnet structure and material chemistry.
Filing growth compares 2021 (2 records) with 2024 (2) — 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 352 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Hard ferrite permanent magnets — strontium and barium ferrite compositions used in motors, sensors and consumer devices — sit at the intersection of ceramics processing and magnetic materials engineering. This landscape covers 352 published records filed against calcination, wet pressing, lanthanum-cobalt substitution, remanence improvement, grain growth control and maximum energy product claims between 2015 and mid-2026. The scope favours process and composition claims over end-use applications, so it reads as a map of how ferrite magnets are made rather than where they are deployed.
Publication lags filing by roughly 18 months, so the most recent one to two years in any trend understate real filing activity. Treat 2024 as the last complete year and read 2025-2026 as still filling in.
Filing trend and technology composition
Two views of the same 352-record dataset: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
A plateaued filing curve
Filings ran from 5 in 2017 to a peak of 8 in 2022, then held flat — 2021 to 2024 shows 0% net change (2 filings in both years). This is a field with steady, low-volume filing rather than a growth trajectory; 2025-2026 figures will rise somewhat as publication catches up but are not yet comparable.
Magnet structure claims dominate, alloy chemistry runs second
H01F (magnets, inductors and transformers) appears in 91.8% of the 352 records, confirming this is fundamentally a magnet-structure field. C22C (alloys) at 42.0% and C04B (ceramics) at 20.2% show the two main material routes into that structure — metallic alloy substitution versus ceramic processing — while B22F powder metallurgy (19.6%) and C01G metal compounds (14.5%) mark the powder-preparation stage most filings must also cover.
Shares are the percentage of the 352 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Ferrite Permanent Magnets and Hard Ferrite Powder with Eureka
This page is one run against one query. Ask Eureka your own question about ferrite permanent magnets and hard ferrite powder and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
Resin-bonded magnet, its product, and ferrite magnet powder and compound used therefor
Filed by Hitachi Metals, this record claims a resin-bonded magnet combining an R-T-N rare-earth magnetic powder with a ferrite magnetic powder of magnetoplumbite-type crystal structure, where the ferrite component is a strontium or barium oxide substituted with rare earth elements including lanthanum. The claim structure ties powder composition ratios directly to magnet performance.Published 2002-07-04 — one of the earlier records in scope and a useful reference point for how composition-ratio claims in this field are structured.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5806346A | Magnetic pendant necklace set and manufacture | 151 |
| 2 | US6139766A | Oxide magnetic material, ferrite particles, sintered magnet, bonded magnet, magnetic recording medium, and mo… | 96 |
| 3 | US5886070A | Production method for anisotropic resin-bonded magnets | 80 |
| 4 | US6695929B2 | Method of making material alloy for iron-based rare earth magnet | 59 |
| 5 | EP0905718A1 | Oxide magnetic material, ferrite particle, sintered magnet, bonded magnet, magnetic recording medium and motor | 59 |
| 6 | US5846449A | Magnet powder, sintered magnet, bonded magnet, and magnetic recording medium | 46 |
| 7 | EP0758786A1 | Magnet powder, sintered magnet, bonded magnet, and magnetic recording medium | 44 |
| 8 | US4022701A | High-performance anisotropic plastics magnet and a process for producing the same | 44 |
| 9 | US20030019546A1 | Nanocomposite magnet and method for producing same | 39 |
| 10 | US20040099346A1 | Compound for rare-earth bonded magnet and bonded magnet using the compound | 36 |
Citation counts favour older filings that have had more time to accumulate references — treat them as a signal of influence within this corpus, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once the ranking, trend and classification data are read together.
The field is claimed, not open
With 254 of 352 records held by five assignees, new entrants are filing into dense prior art rather than a green field. The leader alone accounts for 131 records — filing strategy here means designing around established composition and process claims, not staking out fresh territory.
A mature, steady-state technology
Peak filing (8 records in 2022) has not been sustained or exceeded; the 2021-2024 span nets to zero growth. High historical filing density here signals occupied claim space, not an actively expanding technology — a different calculus than a field still ramping up.
Two material routes converge on one structure
Nearly all records touch H01F magnet structure claims (91.8%), but a substantial share also claim alloy chemistry (C22C, 42.0%) or ceramics processing (C04B, 20.2%). Filings that only address one material route without the structural claim are comparatively rare in this set.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to ferrite permanent magnets and hard ferrite powder, with the prior art for and against each one.
Assignee concentration and recent momentum
The ranked list covers 52 companies across the full 352-record dataset — not a top-50 or top-100 cut, but the entire set the data endpoint returns.
One assignee holds more than a third of the field
The leading assignee's 131 records against a 352-record total means any competitive filing in this space is, in practice, filing against one dominant portfolio first and the rest of the field second.
A steep drop after the leaders
Fifth place holds 14 records; tenth place holds 5. The gap between the top five and the next five is proportionally larger than the gap within the top five itself, marking a real tier boundary rather than a gradual taper.
Filing is mostly solo, with one dense internal pair
Only 10 co-assignee pairs appear across the dataset, and the strongest pair — the field's leading company filing jointly with a materials-focused partner — recurs 9 times, well above the next pairings. Co-filing here looks more like a captive internal relationship than an open collaboration pattern.
| Assignee | Recent year | YoY |
|---|---|---|
| Sumitomo Special Metals Co., Ltd. | 0 | — |
| Proterial, Ltd. | 0 | — |
| TDK Corporation | 0 | — |
| Fuji Electrochemical Co., Ltd. | 0 | — |
| Aichi Steel Corporation | 0 | — |
| Murata Manufacturing Co., Ltd. | 0 | -100% |
| Santoku Corporation | 0 | — |
| Tokin Corporation | 0 | — |
Where to take this analysis
The dataset points to specific follow-up work depending on whether the goal is freedom-to-operate, competitive tracking or white-space filing.
Run a freedom-to-operate check against the top five
With 72.2% of records held by five assignees, any new filing should be checked against those portfolios specifically, not the field as a whole.
Explore assignee portfolios in EurekaTrack the under-claimed IPC branches
B22D, C21D and H02K overlaps sit well below the H01F/C22C core — worth a deeper claim-by-claim read before assuming the gap is real.
Search white space in EurekaWatch for the 2025-2026 publication catch-up
Filing counts for the most recent two years will rise as publication lag closes; re-check the trend in six to twelve months rather than treating current figures as final.
Set up monitoring in EurekaCommon questions on ferrite magnet patents
One assignee leads with 131 of the 352 records in this dataset, and the top five combined hold 254 records — 72.2% of the field. This is a concentrated landscape: the leading company's portfolio needs to be checked first in any freedom-to-operate review, since the next tier drops off steeply, with fifth place at only 14 records.
Not on the recent evidence. Filing peaked at 8 records in 2022 and the 2021-to-2024 span nets to 0% growth, moving from 2 filings to 2 filings. This reads as a mature, steady-state technology rather than one in active expansion, though publication lag means 2025-2026 figures are still incomplete and will rise somewhat as more records publish.
The records in this dataset centre on strontium and barium ferrite compositions (magnetoplumbite-type structures), which are lower-cost and lower-performance than rare-earth alternatives like neodymium magnets. Several records, including the representative filing here, combine a rare-earth magnetic powder with a ferrite powder in a single resin-bonded magnet, suggesting the two material families are often claimed together rather than as pure substitutes.
H01F (magnets, inductors and transformers) appears in 91.8% of the 352 records and is effectively the base classification for this field. C22C (alloys, 42.0%) and C04B (ceramics, 20.2%) mark the two competing material-processing routes, while B22F (powder metallurgy, 19.6%) covers the powder-preparation step that most filings also need to address.
Relative to the dense H01F and C22C core, classes like B22D (metal casting), C21D (heat treatment for grain growth) and H02K (motor integration) show markedly lower record counts. That does not guarantee an open filing path — it means those branches warrant a closer claim-by-claim read before assuming freedom to file, since thinner coverage can also reflect fewer viable technical approaches rather than unclaimed space.
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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.