Plasma Electrolytic Oxidation Patents: Top Companies & Trends 2026
- Filing has cooled since 2017. the peak year in this dataset, with the 2022 midpoint back at the same level and no rebound through the most recent full year.
- The top 5 assignees hold 54.8% of all 115 records and the top 10 hold 73.0% — a field concentrated at the top with a long tail of single- or few-filing entrants.
- Almost every record sits inside C25D, but a quarter also touch C23C coating deposition, and smaller pockets reach into medical (A61B, A61L) and electronics (H01J, H05K) applications.
What this landscape covers
Plasma electrolytic oxidation, also called micro-arc oxidation, grows a ceramic-like oxide layer on light metals — chiefly aluminium, magnesium and titanium — using high-voltage discharges in an electrolytic bath. The claims in this dataset cluster around electrolyte composition, coating porosity control, dielectric breakdown management and corrosion resistance on magnesium substrates, reflecting the process variables that determine whether a coating is dense, adherent and defect-free rather than porous and prone to arcing damage.
The 115 records in scope span 2015 through the 2026 cut-off, with publication data understating the most recent year or two because filings typically publish around 18 months after they are filed. Receiving-office activity is led by the United States, followed by Europe and WIPO/PCT filings, with the United Kingdom, South Korea and China each contributing a smaller but present share.
Filing trend and technology composition
Two views of the same 115 records: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
A peak in 2017, then a flat-to-declining trend
Filings hit 9 in 2017, the high point of the series, then eased back to the same level of 9 by the 2022 midpoint before declining further toward the 2026 cut-off, where the single record on file reflects publication lag as much as any real slowdown.
Concentrated in electroplating and electroforming, with real spillover
C25D (electroplating and electroforming) appears in 99.1% of the 115 records, which is expected given the search construction, but C23C (coating and surface deposition) reaches a genuine 25.2%, and H01J (electron and discharge tubes) sits at 13.9% — evidence that PEO/MAO claims are increasingly written for plasma-chamber and vacuum-equipment components, not just structural metal parts.
Shares are the percentage of the 115 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Plasma Electrolytic Oxidation (PEO/MAO) with Eureka
This page is one run against one query. Ask Eureka your own question about plasma electrolytic oxidation (peo/mao) and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records in this dataset
Electrolyte composition and method of use thereof (US20220056610A1)
Provided herein is an electrolyte composition including a metal silicate or a metal aluminate, a metal phosphate, zinc oxide particles, and a complexing agent useful for plasma electrolytic oxidation treatment of a surface of a metal substrate.Filed by City University of Hong Kong; published 2022-02-24.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6896785B2 | Process and device for forming ceramic coatings on metals and alloys, and coatings produced by this process | 78 |
| 2 | WO2003083181A2 | Process and device for forming ceramic coatings on metals and alloys, and coatings produced by this process | 76 |
| 3 | WO2008120046A1 | Method of forming a protective ceramic coating on the surface of metal products | 48 |
| 4 | US20140295670A1 | Dense oxide coated component of a plasma processing chamber and method of manufacture thereof | 46 |
| 5 | US20030188972A1 | Process and device for forming ceramic coatings on metals and alloys, and coatings produced by this process | 40 |
| 6 | US20110297319A1 | Reduction of Copper or Trace Metal Contaminants in Plasma Electrolytic Oxidation Coatings | 29 |
| 7 | WO2007073213A1 | Micro-arc assisted electroless plating methods | 16 |
| 8 | CN1978712A | 有色金属制品微弧氧化处理的局部屏蔽方法 | 16 |
| 9 | US20090223829A1 | Micro-Arc Assisted Electroless Plating Methods | 15 |
| 10 | US20180141310A1 | Object comprising a fiber reinforced plastic and a ceramic material and process for making the object | 12 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside the searched corpus; treat this as a signal of influence on the field's vocabulary, not of current commercial importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns worth acting on before drafting or filing in this space.
The core claim space is occupied by a handful of filers
With the top 5 assignees holding 54.8% of the 115 records in scope and the top 10 holding 73.0%, the foundational ceramic-coating process claims are largely staked out. New entrants are more likely to find room in application-specific formulations than in the base process itself.
Filing activity has not grown since its 2017 peak
The trend returns to 9 filings at the 2022 midpoint, matching the earlier peak rather than exceeding it, and tails off toward the 2026 cut-off. That flat-to-declining pattern, combined with top-filer momentum showing zero recent-year activity for several leading assignees, suggests the field is past its first wave of active prosecution.
Claims are spreading into coating deposition and discharge-tube equipment
Beyond the near-universal C25D presence, a quarter of records also carry C23C coating-deposition classification and close to one in seven carry H01J electron/discharge-tube classification — evidence that PEO/MAO is being claimed for semiconductor and plasma-chamber hardware, not only structural metal parts.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to plasma electrolytic oxidation (peo/mao), with the prior art for and against each one.
Who is filing, and where the gate stands
The ranked leaders show a concentrated top with wide gaps between the leader and the rest, and a long tail of assignees filing once or twice.
A clear leader, then a steep drop
The top-ranked assignee holds 22 records, well ahead of fifth place at 7 and tenth place at 3 — a gap that indicates one filer has built a genuinely broad portfolio rather than the field being evenly split among several comparable players.
Co-filing is present but limited
Ten co-assignee pairs appear in the dataset, with the strongest pairs repeating across three shared filings each. This points to a small number of stable working relationships rather than broad industry-wide joint development.
Several leading filers show no recent-year activity
Multiple assignees that anchor the top of the ranking recorded zero filings in the latest year, with at least one showing a -100% year-on-year change. Combined with the flat overall trend, this suggests consolidation of existing claims rather than a fresh filing push from incumbents.
| Assignee | Recent year | YoY |
|---|---|---|
| MKS Instruments, Inc. | 0 | — |
| Isle Coat Ltd. | 0 | — |
| Keronite International Limited | 0 | — |
| Cirrus Materials Science Ltd. | 0 | — |
| Covidien LP | 0 | — |
| Metal Improvement Co. LLC | 0 | -100% |
| Metalmembranes.com | 0 | — |
| Freni Brembo S.p.A. | 0 | — |
Where to take this analysis
The dataset points to a mature core process and several smaller branches still open for claims.
Map the white space before drafting
The under-claimed branches above have real classification presence but no dominant filer — worth a freedom-to-operate check before committing claim language.
Explore white space in EurekaWatch the leader's recent filings closely
A single assignee holds 22 of the 115 records; understanding what it has claimed most recently narrows where a new filing can safely sit.
Track assignee activity in EurekaCommon questions about PEO/MAO patents
Plasma electrolytic oxidation (PEO), also called micro-arc oxidation (MAO), is patented mainly as a way to grow a hard, adherent ceramic oxide layer on light metals such as aluminium, magnesium and titanium. In this dataset the claims concentrate on electrolyte composition, control of coating porosity, and corrosion resistance on magnesium substrates. A smaller but meaningful share of filings apply the process to plasma-chamber and discharge-tube components rather than structural parts, so the intended end use varies a lot from filing to filing.
The ranking covers 57 companies, and it is concentrated: the top 5 hold 54.8% of the 115 records in scope and the top 10 hold 73.0%. One assignee leads clearly with 22 records, well ahead of the fifth-place holder at 7 and tenth place at 3. Beyond the leaders there is a long tail of assignees with only one or two filings each, which is typical of a process technology with an established core and many peripheral applications.
Filing activity peaked in 2017 at 9 records and, by the 2022 midpoint, was back at the same level of 9 rather than higher, indicating a flat rather than growing trend. It tails off further toward the 2026 cut-off, though the most recent one to two years should be read cautiously because publication typically lags filing by around 18 months. Several of the top-ranked assignees also show zero filings in the latest year, reinforcing that the field is not in an active growth phase.
Almost all records in this dataset — 99.1% — carry C25D, the electroplating and electroforming class, which is expected given how the search was constructed. A quarter (25.2%) also carry C23C, coating and surface deposition, and 13.9% carry H01J, electron and discharge tubes, showing meaningful overlap with plasma-chamber equipment. Smaller pockets extend into A61B and A61L for medical applications and H05K and B32B for electronics and laminate structures, since a single record can carry several IPC codes at once.
The classification data shows real but modest activity in branches like discharge-tube plasma-chamber coatings, medical sterilisation and surgical device coatings, printed-circuit assembly applications, and layered laminate structures — none of which has a dominant filer the way the core ceramic-coating process does. These are worth checking for freedom to operate before drafting, since they sit inside a field with heavy concentration at the top but lighter claim density in the adjacent branches. A first claim there would likely need to tie the PEO/MAO process step to the specific end-application geometry or material stack rather than claiming the coating process alone.
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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.