Our specialties.

Processes

Surface finishing processes for different requirements

Aurolia offers a range of processes for the targeted finishing of technical surfaces. Depending on the material, component and application, properties such as corrosion protection, wear resistance, electrical conductivity, dimensional accuracy and appearance can be specifically influenced. The functional requirements of your component determine which surface treatment is best suited to your application.

Our Processes at a Glance

Passivation of Aluminium

Corrosion protection meets electrical conductivity

Description

Aluminium passivation is a chemical conversion process used to protect aluminium surfaces against corrosion without significantly altering the specific properties of the base material.

Unlike anodising or hard anodising, passivation does not create a thick, electrically insulating oxide layer. Instead, the aluminium surface is provided with a very thin, transparent protective conversion layer.

The key advantage is that the electrical conductivity of the surface is largely retained while the corrosion resistance of the aluminium is significantly improved.

Aluminium passivation is therefore particularly suitable for technical components where electrical contact, EMC properties, equipotential bonding or very tight dimensional tolerances are important.

At Aurolia, aluminium passivation is chromium(VI)-free and RoHS-compliant. The process therefore combines functional corrosion protection with the requirements of modern and sustainable industrial applications.

The process becomes particularly interesting when different properties are required within a single component. For example, anodised or hard-anodised areas can be combined with specifically passivated surfaces. This makes it possible to combine wear- or corrosion-resistant areas with electrically conductive contact surfaces on the same component.

Key facts

Our aluminium passivation offers:

  • chromium(VI)-free passivation
  • RoHS-compliant surface treatment
  • high corrosion protection for aluminium components
  • retention of electrical conductivity
  • very thin and virtually dimensionally neutral conversion layer
  • transparent or largely colour-neutral surface
  • suitable for components with tight dimensional and fitting tolerances
  • ideal for electrical contact surfaces and equipotential bonding
  • suitable for EMC-relevant applications
  • partial passivation of defined functional areas possible
  • can be combined with anodised and hard-anodised surfaces
  • suitable for complex technical aluminium components

Do you have specific requirements for corrosion protection, conductivity or dimensional accuracy?

We will be happy to work with you to determine the appropriate surface solution for your component.

Typical applications

Aluminium passivation is used wherever corrosion protection needs to be combined with functional electrical properties.

Typical applications include mechanical and plant engineering, electronics and electrical engineering, automotive and vehicle technology, defence applications, heat sinks and electronic housings, measurement and sensor technology, as well as technically demanding precision components.

Passivation offers particular advantages for components with contact surfaces, ground connections or EMC requirements compared with electrically insulating surface treatments.

FAQ – Aluminium Passivation

During passivation, the aluminum surface is transformed by a chemical reaction into a very thin protective conversion coating. This improves corrosion resistance without applying a conventional metallic coating to the component.

In the passivation process described here, the reaction between the aluminum surface and a treatment solution creates a very thin, corrosion-inhibiting conversion coating. Both the aluminum surface and components of the treatment solution are involved in its formation. The exact composition of the protective coating depends on the process used.

The aluminum base material remains electrically conductive. However, for electrical contact, the contact resistance of the treated surface is the decisive factor.

Suitable passivation processes enable low contact resistance and can therefore be used for electrical contact surfaces. The achievable values depend, among other factors, on the process, the alloy, and the contact conditions. Requirements for electrical contact should therefore be coordinated before treatment.

The conversion coating formed during passivation is extremely thin. As a result, compared with anodized, hard-anodized, or electroplated coatings, there are virtually no relevant dimensional changes.

The process is therefore particularly suitable for precision components and parts with tight fit and dimensional tolerances.

Yes. Aurolia offers chromium(VI)-free aluminum passivation.

The process therefore meets modern requirements for sustainable surface treatment processes and is suitable for applications where RoHS compliance is required.

In the chemical passivation process described here, a very thin conversion coating is formed through the reaction of the surface with the treatment solution. Depending on the process, it can combine corrosion protection with low electrical contact resistance.

During anodizing, aluminum is converted into a significantly thicker aluminum oxide layer using electric current. This layer is electrically insulating and, depending on the process design, can meet requirements for corrosion protection, wear resistance, and appearance.

Which treatment is suitable depends on the function of the component.

Yes, treating defined partial areas is generally possible. Depending on the component geometry and the process, this can be achieved through localized treatment or suitable masking.

The required areas, their accessibility, and the permissible transitions to adjacent surfaces should be coordinated based on a technical drawing.

Yes. This combination offers particularly useful possibilities for technically demanding components.

Large areas of a component can, for example, be anodized, while specific areas can be designed to remain conductive for electrical contact or equipotential bonding.

This makes it possible to meet different functional requirements within a single component.

The process is particularly suitable for components where corrosion protection needs to be combined with electrical conductivity.

Examples include electronic housings, heat sinks, grounding and contact surfaces, EMC-relevant components, electrical engineering components, and high-precision aluminum components with tight tolerances.

Your requirements determine the surface

Passivation, anodising or hard anodising?

The process should not dictate the solution. The future function of your component should determine the appropriate surface treatment.

Our experts work with you to analyse the requirements for corrosion protection, electrical conductivity, dimensional accuracy, wear resistance and appearance and use these requirements to develop the appropriate surface solution.

Talk to us about your application.