Plasma Nitriding Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled since its 2020 peak. 29 records that year against 9 in the most recent (partial) year — publication lag explains part of the drop, but the 2022 midpoint of 25 already shows the curve flattening before the fall.
- One filer holds a lead no one else approaches. The top assignee alone accounts for 34 records; the top 5 combined reach 100 records, just 14.5% of the 689 in scope, so most of the field sits in a long tail of smaller filers.
- China now receives more filings than any other office. 214 records at the Chinese office lead the United States (119), Japan (90) and the EPO (80) — a shift worth tracking if you are deciding where freedom-to-operate matters most.
What this dataset covers
This landscape tracks patent activity in plasma nitriding, nitrocarburizing and ion nitriding, scoped to records that discuss compound-layer formation, diffusion-zone depth, white-layer control, wear resistance or distortion, and classified under coating & surface deposition, metal heat treatment or plasma-assisted coating IPC codes. The 689 records in scope run from 2015 through the 2026-07-31 data cut-off, giving a decade-long view of how claim activity in this niche of surface engineering has moved.
The technology sits at the intersection of automotive powertrain components, bearing steel, and titanium implant surface treatment, which is visible in the mix of receiving offices and the assignee list. Because publication typically lags filing by roughly 18 months, the most recent one or two years in any trend chart will understate actual filing activity.
Filing trends and technology composition
The two views below chart the same 689 records from different angles: one by filing year, one by IPC subclass. Both use the full record count as their denominator, so the shares are directly comparable.
A peak in 2020, then a flattening curve
Filings ran at 27 in 2017, climbed to a peak of 29 in 2020, and had fallen to 9 by the most recent (partial) year. The 2022 midpoint of 25 already sits below peak, which points to a genuine slowdown rather than a single bad year — though the last one or two years are always undercounted due to publication lag.
Coating and heat-treatment codes dominate, but overlap is heavy
C23C (coating & surface deposition) appears on 96.2% of the 689 records, and C21D (heat treatment of metals) on 29.2%, confirming this is fundamentally a surface-coating field with heat treatment as a secondary lens. Smaller shares in C23F (corrosion, 5.4%), F16C (bearings, 3.6%) and F16D (clutches & brakes, 3.0%) mark where nitriding claims reach into specific mechanical applications rather than staying generic.
Shares are the percentage of the 689 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Plasma Nitriding and Nitrocarburizing with Eureka
This page is one run against one query. Ask Eureka your own question about plasma nitriding and nitrocarburizing and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this space
US5334264A — Titanium plasma nitriding intensified by thermionic emission source
This 1994 patent from Louisiana State University describes ion nitriding of pure titanium or titanium alloys at low pressure, intensifying the glow discharge with a thermionic emission source in a triode configuration. Processing at a relatively low 480°C produced a TiN surface layer, a Ti2N sublayer and an interstitial nitrogen diffusion zone, with treated specimens showing a three-fold increase in surface hardness.Filed decades before the current filing window, this record still frames how later compound-layer and diffusion-zone claims in titanium nitriding are written and read against.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5380547A | Method for manufacturing titanium-containing orthopedic implant devices | 69 |
| 2 | US6110571A | Duplex coated steel composite products and method of manufacturing them | 65 |
| 3 | US20110293849A1 | Method for producing a brake disc | 55 |
| 4 | US20080000550A1 | Salt Bath Ferritic Nitrocarburizing of Brake Rotors | 50 |
| 5 | US6179933B1 | Surface treatment of rolling element bearing steel | 46 |
| 6 | US4563223A | Corrosion resistant steel components and method of manufacture thereof | 44 |
| 7 | US4597808A | Process for ion nitriding aluminum or aluminum alloys | 41 |
| 8 | US5244375A | Plasma ion nitrided stainless steel press plates and applications for same | 40 |
| 9 | CN103805996A | 一种金属材料表面先镀膜再渗氮的复合处理方法 | 39 |
| 10 | JP1983096815A | Heat treatment for cast iron | 37 |
Ranked by citation count within the searched corpus. Older records accumulate more citations simply by being available longer, so treat this as a signal of influence, not of current technical relevance.
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 you commit search or drafting time to this space.
The lead is real, but the field isn't a duopoly
The leading assignee holds 34 records outright, well ahead of fifth place at 14 and tenth at 12. Yet the top 5 combined only reach 14.5% of all 689 records in scope, and the top 10 reach 23.8% — meaning more than three-quarters of filing activity sits outside the ranked leaders, spread across a long tail of one- and two-patent filers.
Recent activity has gone quiet at the top
Several of the historically most active assignees recorded zero filings in the latest year tracked. Combined with the drop from 29 filings at the 2020 peak to 9 in the most recent partial year, this suggests the leading names have slowed rather than a single competitor stepping back.
China now outpaces the US, Japan and Europe combined receiving offices individually
China's 214 filings lead the United States (119), Japan (90) and the EPO (80). Anyone assessing freedom-to-operate risk for manufacturing or sales in China should treat this as the office with the deepest prior art to search first.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to plasma nitriding and nitrocarburizing, with the prior art for and against each one.
Who is filing, and where the claim space is thin
The ranked leaders come from steel, automotive and surface-treatment supply chains, with a research-university presence in Russia. Co-assignment is rare — only 10 co-assignee pairs appear across the dataset — which means most of this field is claimed by single entities rather than joint ventures.
Steel producers hold the deepest single-filer position
The leading assignee's 34 records, reinforced by a related co-assignee pairing at 13 records, point to a steel and bar-products filer treating nitriding process control as core IP rather than a peripheral technique.
Bearing and brake component claims are a minority but persistent slice
Automotive-linked assignees file into bearing (F16C) and clutch/brake (F16D) subclasses at low but steady shares, reflecting nitriding's role in wear-resistant rotating and friction components rather than flat coatings alone.
Established surface-treatment names have gone quiet recently
Multiple assignees with long filing histories in this dataset show no filings in the latest year tracked, which may reflect a maturing claim position, a shift to trade secret protection, or simply the publication lag understating true recent activity.
| Assignee | Recent year | YoY |
|---|---|---|
| JFE Steel Corporation | 0 | — |
| AB SKF | 0 | — |
| FEDERALNOE GOSUDARSTVENNOE BYUDZHETNOE OBRAZOVATELNOE UCHREZHDENIE VYSSHEGO OBRAZOVANIYA UFIMSKIJ GOSUDARSTVENNYJ AVIATSIONNYJ TEKHNICHESKIJ UNIV | 0 | — |
| Oerlikon Surface Solutions AG, Trübbach | 0 | — |
| Toyota Central R&D Labs., Inc. | 0 | — |
| JFE Bars & Shapes Corp. | 0 | — |
| GM Global Technology Operations LLC | 0 | — |
| Biotyx Medical (Shenzhen) Co., Ltd. | 0 | — |
Where to take this analysis
The figures above establish the shape of the field. Turning that into a filing or freedom-to-operate decision requires drilling into specific claims and assignees.
Map claim boundaries around the cited leaders
Start with the most-cited records and trace how their compound-layer and diffusion-zone claims have been narrowed or challenged since filing.
Explore citation trees in EurekaTrack the quiet leaders for renewed activity
Several top assignees show zero recent filings — set alerts so a resumption in filing doesn't arrive as a surprise.
Set assignee monitoring in EurekaStress-test the under-claimed branches
Before drafting into non-ferrous diffusion control or corrosion-resistant compound layers, confirm the thin density holds up against the full underlying document set.
Run a white-space search in EurekaCommon questions about plasma nitriding patents
This dataset identifies 689 published records classified under coating, heat-treatment and plasma-coating IPC codes and matching plasma nitriding, nitrocarburizing or ion nitriding terminology, spanning 2015 through the 2026-07-31 data cut-off. That figure covers a specific search scope tied to compound-layer, diffusion-zone, wear-resistance and distortion terminology, so a broader or narrower search string would return a different total. Because publication lags filing by roughly 18 months, the true count for the most recent one or two years is understated in any snapshot taken today.
The ranked leader in this dataset holds 34 records, with the fifth-placed assignee at 14 and the tenth at 12 — a clear lead at the top but not a runaway monopoly. The top 5 assignees combined account for 100 records, or 14.5% of all 689 records in scope, and the top 10 reach 23.8%, meaning most filing activity sits with entities outside the ranked leaders. Filers cluster around steel and bar products, automotive components (bearings, clutches, brakes) and surface-treatment equipment suppliers.
Filing activity peaked at 29 records in 2020, up from 27 in 2017, but had declined to 9 by the most recent partial year, with the 2022 midpoint already back down to 25. That trajectory points to a genuine slowdown rather than a temporary dip, though the last one or two years always look artificially low because of publication lag. Several previously prolific assignees recorded zero filings in the latest year tracked, reinforcing the flat-to-declining read.
US5334264A, filed by Louisiana State University's Board of Supervisors, covers ion nitriding of titanium and titanium alloys at low pressure using a thermionic-emission-intensified triode glow discharge, producing a TiN/Ti2N compound layer and diffusion zone at around 480°C. It is a 1994 filing, so its core claims are long past their enforceable term, but it remains a heavily cited reference point that later titanium nitriding claims are drafted and examined against. New filings in titanium plasma nitriding should expect examiners to cite it as foundational prior art for the compound-layer and diffusion-zone structure it describes.
The IPC composition shows heavy concentration in coating (C23C, 96.2% of records) and heat treatment (C21D, 29.2%), with much thinner coverage in non-ferrous metal treatment (C22F, 3.0%), metal-working process integration (B23P, 3.3%) and corrosion-resistant applications (C23F, 5.4%). Those thinner branches, along with specific niches like low-temperature triode glow-discharge systems for titanium implants, show less claim density relative to the core coating classes. Thin density is not proof of an easy filing — it means the branch is under-explored in this corpus, and a full freedom-to-operate search is still required before drafting.
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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.