improves the corrosion resistance of alloys
Nitrotec®
what is Nitrotec®?
Nitrotec® (nitriding-oxidising-protection) is a patented thermo-chemical diffusion process, during which the surface of steels is nitrocarburized and next oxidized, cooled and – if requested – sealed. Nitrotec® combines the useful properties of the nitrocarburizing (improved surface hardness and wear resistance, enhanced fatigue strength, nihil distortion) with the high resistance against atmospheric corrosion, increased yield strength and an attractive black finish.
Nitrotec®-layers are created in nitrogen and carbon submitting gaseous atmospheres at temperatures between 540-740⁰C. The treatment generates compound layers, supported by nitrogen rich diffusion zones in the base material. The choice of process temperature, time and nitrogen potential of the atmosphere in relation to the type of steel, controls the structure, composition and hardness of the compound layer and the diffusion zone underneath. The innovative oxidation technique and the special water based quenchants, as well as the organic sealing are based on the technical demands for the application.
At the surface an iron oxide layer (Fe3O4) is formed for improvement of the corrosion resistance of the material. Underneath the oxide layer a compound layer is present, which consists of iron nitrides, iron carbides and nitrides or carbonitrides of the alloying elements. At process temperatures above 590⁰C, a nitrogen-rich austenite layer is formed between the compound layer and diffusion zone. The transition to the core is formed by the diffusion zone, which consist of iron (ferrite)matrix, supersaturated with nitrogen and possibly precipitated nitrides.
special properties after the process
In common with other low temperature surface treatments, Nitrotec® does not introduce distortion into the part, this means that components can be used and fitted directly after treatment.
The conventional Nitrotec® has a pleasing black appearance and vastly superior corrosion resistance to zinc plating. These low temperature diffusion treatments make low alloy and mild steels up to four times stronger, produce wear resistance equal to hard chromium plating and result in a black finish that has outstanding resistance to corrosion.
another Nitrotec® process: NITROTEC®-S
An important member of the Nitrotec® family of treatments is NITROTEC®-S, a multi-stage process in which parts are first machined to a final surface finish, treated with Nitrotec®, surface polished in a controlled manner and then subjected to a post-oxidation treatment.
This finish results in a drastic improvement in friction properties and corrosion resistance that is superior to the use of hard chrome plating techniques.
benefits of Nitrotec®
Wear resistance, improved fatigue performance and excellent corrosion resistance are among the properties imparted by this modern surface treatment technology. Such performance improvements can significantly reduce the manufacturing and material costs of components, as the automotive industry has repeatedly demonstrated on pressed parts.
- Abrasion resistance
- Corrosion resistance
- Weight saving
- Reduced material costs
further details on advantages
The surface hardness as well as the specific hardness profiles indicate the capability of Nitrotec treated components to resist indentation from point contact surface loading.
When rapidly cooled after Nitrotec treatment, significant strengthening of thin sections, as for example sheet metal, occurs. This results in an increase in both yield strength of the base material and its fatigue strength.
Nitrotec combined with an organic sealant retained in the micro porous layer, imparts corrosion resistance superior to that of electro plated components, and comparable to that of medium grades of stainless steels. A combination of Nitrotec finishes with a range of organic sealants give salt corrosion resistance with a minimum of 240 hours.
Nitrotec treatments, that are environmentally friendly and clean, ensure that good surface finishes can be maintained.
Nitrotec treatment produces an aesthetically pleasing black/anthracite surface finish.
Traditional hardening practices may give rise to distortion and poor dimensional control, because metallurgical phase changes when rapidly quenching from high treatment temperatures. During Nitrotec treatment these changes do not occur, therefore allowing the treatment of close-tolerance precision parts, especially thin section components.
The layer which is formed during Nitrotec consists of a compound zone which is supported by a nitrogen-austenite layer. The oxide, so-called magnetite, is about 1 μm in thickness and can be increased up to 4 μm when applicable. Also, the thickness of the compound layer is variable pending on the material and the application. Underneath the nitrogen-austenite, the so-called diffusion zone is created.
fields of application
The types of components that are treated with Nitrotec® include: Pistons, Ball Studs and Other Mild Steel Components.
Nitrotec® is a replacement for chromium plating. It is more environmentally friendly and delivers heat treatment of steels and alloys very successfully.
Improvements in performance can significantly reduce the manufacturing and material cost of components, a fact proved repeatedly by the automotive industry as they use treated pressed parts.
benefits from our services, from the idea to series production
- Developing individual innovations
- Clarify detailed questions
- Support from the idea to series production
- First-class support
- Highest quality – whether small or large series
- Certified according to DIN EN ISO 9001:2015, VDA 6.1:2016 and ISO 13485:2016
downloads
frequently asked questions – Nitrotec®
All unalloyed and low-alloyed ferrous materials.
Improved hardness, very good corrosion protection and low dimensional change behavior.
Is not required.
The entire process only takes a few hours.
For more information and specific inquiries about Nitrotec®, you can contact our specialist team directly or visit our official website.
industries we serve
process locations
Any questions? Contact us directly or select a process location near you.
Anderstorp
Sweden 57.265275813.615284 info.nordic@aalberts-st.com +46 371 58 71 70 show locationVenlo (Lomm)
the Netherlands 51.44642316.1786697 info.venlo@aalberts-st.com +31 77 308 1333 show locationBirmingham
United Kingdom 52.5108198-1.8767323 info.birmingham@aalberts-st.com +44 121 322 2280 show locationUnsere Verfahren
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We offer all types of heat treatment processes. Our facilities are closely interlinked in terms of logistics, which means that all processes are available to you. For a complete list and description of heat treatment technologies please select the button.
Hot isostatic pressing (HIP) is used to eliminate porosity. Do you need high mechanical durability and insensitivity to high temperatures for solder joints? We at Aalberts surface technologies offer the solution through brazing.
Polymer coatings can be applied to a wide variety of base materials and offer long-lasting protection. They are particularly well anchored mechanically to the substrate. Additional enhancement layers allow non-stick coatings to be combined with improved sliding properties and/or high wear resistance.
With 40 years of experience in continuous reel to reel finishing, you can depend on Aalberts surface technologies to find innovative solutions that other companies might say are impossible. Our service includes barrel plating, continuous selective plating and rack plating.
Almost all metallic base materials can have their properties optimised by surface coatings using our proprietary and patented processes, regardless of whether they should be particularly hard, smooth, wear-resistant or corrosion-resistant.