Nitrocarburising with post-oxidation (NIOX and ALDOX)

Nitrocarburising with post-oxidation is a complementary process to gas nitriding and gas nitrocarburising. It provides additional corrosion resistance to workpieces and gives them a refined surface finish ranging from anthracite to black. The process coats the workpieces with a thin layer of oxide. To allow this layer to form sufficiently, the materials must be pre-treated by nitriding or nitrocarburising Whether NIOX processes or other state-of-the-art processes: we optimise even the most challenging technical components for you. As a single part, in custom sizes, or as volume production - whatever your requirements are. Feel free to contact us for a personal, no-obligation consultation.

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The process and its advantages

In the NIOX process, the nitrocarburising is followed up by a post-oxidation of the workpieces. In this step, the compound layer produced in the preceding step is partially converted into an oxide layer by dwelling and cooling in an oxidising environment. This layer further increases the corrosion resistance of the workpiece surface.

In contrast to the NIOX process, the ALDOX process involves an intermediate treatment and a further oxidation process. These steps further enhance resistance to corrosion.

Materials made of low-alloy steel benefit especially from a NIOX or ALDOX treatment. As components made of these materials are commonly exposed to great stress (gear spindles, hydraulic cylinders, etc.), they require particularly strong protection against wear and corrosion.


The advantages of the NIOX process at a glance

  • Highest corrosion protection out of all the nitriding processes
  • Greater wear resistance
  • Improved fatigue strength
  • Enhanced resistance to tribological and dynamic mechanical stresses
  • Optimised sliding characteristics
  • Reduced cold weld build-ups
  • Resistant to fluctuating temperatures down to the cryogenic range
  • Pleasing aesthetics
  • Also suitable for treatment of bulk material


Additional advantage of the ALDOX process

The ALDOX process offers even greater corrosion protection, but is also more costly than the NIOX process.

Areas of application

For any application where coatings are used (galvanic, chromated, phosphated, burnished, ...) nitrocarburising and oxidation offer an attractive and high-performance alternative.

Typical components

  • Hydraulic components
  • Hydraulic cylinders and pistons
  • Screw conveyors
  • Pump wheels and enclosures
  • Tools and tool holders
  • Valves
  • Nozzles
  • Non-return valves
  • Gear wheels and chain wheels
  • Moulds, forming tools, dies, and die plates
  • Engine parts
  • Cam shafts and crankshafts
  • Gear parts
  • Spindles
  • Axles
  • Shafts
  • Couplings