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HART-COAT® is a specially developed coating for the functional finishing of aluminium materials (hard anodising).

Why do we marvel at honey bees?

Why do we marvel at honey bees?

Because honey bees have identified the advantages of the hexagonal structure much sooner than we have. Our HART-COAT® process coats materials with a hard, wear-resistant and temperature-resistant surface structure that closely resembles the honeycomb.

The process

As early as the early 1960s, AHC laid the foundation for hard-anodising in Germany with the introduction of the HART-COAT® process. HART-COAT® (or HC) is a specially developed coating for the functional finishing of aluminium materials (also called hard coating). With the help of electric current, the workpiece surface transforms into a hard, ceramic-like aluminium oxide layer. This aluminium oxide layer builds up in the form of regular hexagonal cells, which stand like honeycombs perpendicular to the workpiece surface. The workpiece is thus primarily protected against wear and corrosion.

Hard coating is a particularly versatile hard-anodising coating with different process variants and post-treatment options. Every year, more than half a billion components are hard-coated by AHC to ISO 100 74 standards.

  • Characteristics

    HART-COAT®-layers are very wear resistant and hard as a consequence of the morphology of the aluminium oxide. During hard coating, half of the oxide grows into the base material and half outwards. As a result, the bond between the layer and the base material is exceptionally high. The ceramic-like HART-COAT® layer is a good electrical insulator and has a low thermal conductivity and high dielectric strength. As a protective layer on engine piston bases, it can withstand extremely high temperatures in the short term.

    Special post-treatments make it possible to adapt HART-COAT® coatings to special requirement profiles such as increased wear and corrosion resistance or improved anti-friction properties.

  • Base Materials

    Almost all technically interesting aluminium alloys, be they wrought alloys, cast alloys or die-cast alloys, can be finished with HART-COAT®.

    With components that are being delivered for coating, please note the following:

    • no material, machining or surface defects
    • as free from oil and residue as possible
    • part-specific protective packaging where possible
    • the pre-coating operation should be machining
    • no foreign bodies in the workpiece surface
    • edges and corners well deburred and as rounded as possible
    • tolerances must be taken into account
    • vent holes may be necessary
  • Field of Application

    Due to its good wear resistance, a hard-coated aluminium material can replace expensive wear-resistant steel. The same applies to the replacement of expensive corrosion-resistant materials. Potential applications are where contact corrosion should be prevented, anti-friction properties improved, electrical or heat insulation increased.

    The density of aluminium alloys is about one third of the value of conventional ferrous and non-ferrous metals. By switching from steel or brass to aluminium materials, inertia forces of high-speed machine parts can be substantially reduced. This results in new constructional options and savings in energy costs. The required surface durability is achieved by using HART-COAT®.

    Examples of HART-COAT® hard-anodised components are: spacers, iron soleplates, surgical instruments, damping chambers, nozzles, guide cylinders, housings, fixings, levers, heating plates, insulating bolts, camera parts, rocker arms, clamps, pistons, clutch parts, bearing rollers, bearing shells , baffles, guide rollers, mounting plates, cam discs, pneumatic and hydraulic cylinders, rollers, spools, transport levers, valves, compressor wheels, gears wheels and racks, centrifuges, cylinder heads, cylinder tubes.

    The industrial sectors using HART-COAT®-finished components include, amongst others: gauge construction, automotive, mining, office technology, data technology, energy technology, household appliance industry, food industry, mechanical engineering, medical device construction, measurement technology, pharmaceutical industry, reactor technology, control technology, defence technology.

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

  • Technical anodising

    Technical anodising

    Optimisation of aluminium surfaces - functional and decorative

    to the process
    Technical anodising


    Hard anodising with fluoropolymers

    to the process
  • CompCote®


    Aluminium oxide polymer composite coatings

    to the process


    Plasma chemical coating for the finishing of aluminium and titanium alloys

    to the process

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Aalberts Industries