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Chrome and cadmium substitute

Chrome and cadmium substitute

Alternative, environmetally-friendly coatings.

Are we reducing environmental impact with this?

Are we reducing environmental impact with this?

Yes, because these coating processes have been developed as substitutes for coatings based on chromium(VI) or cadmium, which are considered carcinogenic. In particular, environmentally harmful production processes are eliminated, as are materials on the component surface that can lead to health hazards.

IVD

IVD aluminium vacuum coating was originally developed by McDonnell Douglas as a replacement for cadmium treatment of steel and titanium components.

The sequence of the coating process is as follows: First, the parts are degreased to remove cutting or dewatering oils. The next process step is a fine-grained sandblasting. On the one hand, the surface is mechanically cleaned, and on the other hand, a profile with a large surface is produced. The latter supports the physical bonding of the coating to the substrate.

During the process, the parts are held on an electrically conductive frame in a vacuum coating chamber. The parts are moved into the coating chamber, which is evacuated. An inert gas is introduced into the chamber and an electric voltage is applied. This leads to a plasma glow discharge, which is clearly visible as a violet glow in the chamber. The result is a very clean surface on the substrate.

Once this process is completed, the actual coating process can begin. Aluminium wire is now fed to a series of overheated ceramic crucibles. A high voltage is applied to produce very high temperatures and the aluminium evaporates to an electrically charged mist. The negatively charged aluminium atoms move through the vacuum and deposit on the parts to be coated, which are electrically "grounded".

After coating with IVD aluminium, the parts have a dull grey appearance and must be handled with care. The next step is to close the pores in the outer surface of the coating by glass bead blasting. The parts may be used "as plated" or, more frequently, the pure aluminium surface is converted to an aluminium chromate layer by a chemical conversion coating.

  • Properties

    IVD aluminium offers good corrosion protection even at high temperatures. The coating can serve to prevent bimetallic or galvanic corrosion. The corrosion resistance can be increased in all cases by a subsequent chemical conversion coating.

    Another big advantage of IVD aluminium vacuum coating is that it can be painted with very little surface pretreatment. The surface is suitable for many paints, including commonly prescribed liquid-tight epoxy resin-based primers and dry film lubricants.

  • base material

    Primarily, components made of steel alloys and titanium materials are coated.

  • Application

    Coating with IVD aluminium is primarily used in the aerospace and defence industries.

    One example is the coating of titanium fasteners to which aluminium components are attached.

    The process is certified for NADCAP and for a number of large aerospace companies including Airbus, Boeing, Bombardier, Leonardo, Rolls-Royce, Safran and UTC.

    The components that are coated for these end users can vary in size and complexity to a surprising extent, from small fasteners to larger components such as airframe components, engine components, and composite assemblies.

SurTec® 650

Chromium-free (VI) passivation SurTec® 650 is used in immersion, spraying or wipe application processes. The chemical process produces a faintly iridescent conversion layer. Chromium-free (VI) particles are incorporated into the coating for optimum corrosion protection.

  • Properties

    The chrome-free (VI) passivation SurTec® 650 offers optimum corrosion protection, has low electrical contact resistance and is ideal for after-treatment of anodising layers and as a primer for paints, powder coatings and adhesives.

  • base material

    The chrome-free (VI) passivation SurTec® 650 and aluminium yellow chromating are suitable for almost all technically interesting aluminium alloys. In our plant in Altdorf (CH) the passivation of magnesium is also possible.

  • Application

    The chrome-free (VI) passivation SurTec® 650 is ideally suited for use in the electronics industry due to the low surface resistance as well as for use in the aviation industry because of the high corrosion protection on unpainted surfaces. A third user industry is the automotive industry due to the sum of all characteristics of the passivation layer.

Product enquiry

If you would like to tell us something about the product presented here, you are welcome to do so. Your enquiry, your comment, your wishes will be forwarded directly to your personal contact person.

More Surface Treatments

  • Sealing

    Sealing

    High performance sealing of aluminium surfaces

    to the process
    Sealing
  • Electroless Nickel plating

    Electroless Nickel plating

    Functional finishing of metals by means of electroless nickel plating

    to the process
    Electroless Nickel plating
  • Screw locking

    Screw locking

    Strong bonds

    to the process
    Screw locking
  • Sherardizing

    Sherardizing

    Zinc-iron layer to a steel surface.

    to the process
    Sherardizing

Do you have a question about materials or processes?
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