surface treatments

additive manufacturing needs surface treatment

Surface treatments play an important role in additive manufacturing. The parts coming out of the printers are in most of the cases not yet finished. Corrosion protection, decorative coatings, non-stick properties, wear resistance, sliding coatings, traction coatings give the part the final shape and function to cover the needs of each application and technical environment.

Through the use of environmentally friendly and resource-saving processes in proven production facilities at numerous Aalberts surface treatment Group locations in Europe, Australia, Asia and America, our highly qualified and experienced staff ensure the finest quality and precision in functional surface treatment in order to meet the most stringent customer requirements.

Please have a look at our outstanding surface treatment solutions all with the strong support of our sister company Aalberts surface treatment. We are sure we find a solution fitting to your needs.

process overview have a look at our processes!

Anodizing is suitable for functional as well as decorative finishing of aluminum materials. Aluminium surfaces acquire good corrosion and wear protection. We also offer coloured anodizing coatings. We offer colored coatings for aluminum materials as well as for titanium alloys.

Aluminum alloy components are anodized or hard anodized in an electrolyte with color additives.

Components made from titanium or a titanium alloy are anodized in a special acidic electrolyte. On the surface of the components, a thin, very adhesive titanium oxide layer is formed. The coating thicknesses lie between about 20 to 120 nm and thus are a fraction of the wavelength of visible light. Incident light is reflected by the surface of the actually colourless layer and by the layer base. The coating appears colored due to interference (superposition of light waves).

Dry lubricant anti-friction coatings are designed to reduce friction and surface wear as well as to avoid noises. The coating materials are watersoluble. Various methods of application are possible. The type of application method depends on the geometry and quantity of parts to be coated, the type of liquid coating material used (e.g. single or multiple component system) and the requirements of the final coating. All metals, light metals and plastics intended for industrial use can be treated, depending on the processing type. Depending on the process variant, anti-adhesive properties, wear protection, dry lubrication and corrosion protection are effectively combined.

Cathodic dipping means immersing a negatively charged workpiece in a paint bath containing positively charged particles. The component to be treated attracts the particles, forming an even coating on the entire surface. Once the layer of paint is applied, we finish the process by baking on a protective film. Cathodic dip coating is suitable for high quantities or complicated designs. The created layers are contour true, corrosion-resistant and impact-resistant. Cathodic dipping is an ideal topcoat for zinc surfaces and particularly beneficial for priming a conventional paint or for powder coating.

For chrome and cadmium substitutes, we use a Physical Vapour Deposition (PVD) process and produce a pure, extremely thin aluminium layer in a high-vacuum process. The chromium substitute is suitable for almost all plastics and metals. The cadmium substitute is intended for steel and titanium components. In addition, we offer chromium-free passivations as protective layers on metallic surfaces, which prevent or greatly retard corrosion of the base material. Base materials are aluminium and magnesium. Such coatings are also referred to as chemically produced conversion coatings.

Electroless nickel plating takes place as deposition without an external power source. The performance spectrum of the coatings ranges from chemical resistance, corrosion and wear resistance, dimensional accuracy and optimum anti-friction properties to electrical conductivity and increased hardness. The coatings are deposited uniformly and true to contour. An electroless nickel layer can also be produced with integrated polymers. This forms self-lubricating surfaces with high wear and corrosion protection. The wear resistance is also significantly increased by the inclusion of silicon carbide.

Electrochemical deposition of a thin metallic layer on the surface of a conductive metallic component is called electroplating. This primarily improves the characteristics of a component such as, for example, wear resistance, corrosion resistance or anti-friction properties. A metallic or conductive component is connected to the negative pole (cathode) of a rectifier and placed in a water-based electrolyte in which conductive salts and metal ions of the metal to be deposited are contained. At the same time, the positive pole (anode) of the rectifier is connected to metal plates consisting of the metal to be deposited. Turning on the rectifier, a current begins to flow, which dissolves metal ions in the electrolyte on the side of the anode by oxidation and thus continuously supplies the electrolyte with new metal ions. At the same time, a metal layer is deposited from the enriched electrolyte onto the component, which is attached to the cathode.

Hard anodizing is a particularly versatile coating with various process variants and post-treatment options. Aluminium oxide polymer composite layers are formed through anodic oxidation of the base material and simultaneous molecular bonding of the aluminium oxide layer with polymers. The layers are very wear-resistant and hard, showing increased corrosion resistance or improved anti-friction properties.

With a nanocoating nanoparticles create bond firmly to the surface and ensure that dirt, water and other fluids are repelled (lotus effect). A nanocoating can be applied to virtually all materials. It is temperature-resistant and ideally suited for fine-pored materials and high-precision applications such as ultra-thin non-stick coatings for easy removal of moulded parts from the mould or as a protective film for frequently cleaned surfaces like glass and facades.

Plasma chemical coatings are anodisation processes in which an oxygen plasma discharges at the surface of the material during the process. They are suitable for the refining of magnesium, aluminium and titanium alloys. In addition to excellent wear protection and improved corrosion protection, the coatings offer absolute contour accuracy and dimensional stability as well as hardness. Plasma-chemically coated substrates have a much higher bending fatigue strength than substrates with conventionally anodised layers.

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. The use of special polymers allows hydrophobic surfaces to be created and reliably prevents various substances, such as adhesives, rubber, synthetic materials or food ingredients, from sticking to these surfaces. The targeted alteration of the surface structure using defined roughness profiles enhances the non-stick effect by reducing the contact area. Our polymer coatings are FDA-approved and therefore used primarily for food production.

In powder coating, the electrical effects support the even coating by the paint powder. Through a subsequent thermal treatment, the melting powder forms a uniform and very well adhering surface coating. The layers produced have very good scratch resistance, high impact protection and excellent corrosion protection. They are very weather and temperature resistant. In addition to excellent functionality, powder coating offers a wide range of decorative possibilities: We have an extensive colour palette with all shades from the Pantone, NCS and RAL colour systems.

Vibrations and movement of materials are detrimental to the security of connections and can lead to instability. We at Aalberts surface treatment have developed high-performance coatings that we apply to screw connections subject to extreme stress – enabling them to resist unusually high strain. For screw locking, we have all the coatings required on the market and all licensed coatings available. Our thread locks are used primarily in the automotive industry and the construction industry – where people and machines have to be reliably protected. We coat all kinds of connecting elements, in many different sizes and screw variations, to make them more secure and to improve sealing: screws, nuts, grub screws and special parts such as elbow fittings.

The surfaces of aluminium alloys and anodising layers are sealed with the aid of a dipping varnish. Very even layers are created, even on complex components with internal surfaces such as drill holes or cavities. Sealing the surface increases corrosion resistance and significantly increases alkali resistance. It is biocompatible and food safe according to FDA regulations.

Selective coating means precise treatment of defined surface areas. The advantage of the selective coating is that any mechanical reworking of the surface is eliminated. Component surface areas which are to be left uncoated are covered, inside a tool, with an integrated sealing system. An electrolyte is pumped from a reservoir into the tool and it passes between the free component surface and the tool housing. We are able to create selectively a hard anodised layer on defined areas of a component. On the other hand, we can also partially deposit metal, such as hard chrome and gold. While with hard anodising and hard chrome wear resistance is in the foreground, the main characteristic with gold is the electrical conductivity. For partial wear protection of aluminum components, partial oxidation by laser may be considered.

Sherardizing is a coating process that uses thermal solid phase diffusion to apply a zinc-iron layer to a steel surface. This is why it is often referred to as zinc thermal diffusion. The resulting intermetallic zinc iron phases bond atomically to the base material , ensuring excellent protection from corrosion. When this procedure is used, no hydrogen-induced corrosion or molten metal embrittlement occurs. Zinc diffusion is well suited for many types of base steel. With sheradizing the controlled diffusion creates a microcrystalline Zn/Fe structure that serves as an excellent base for additional protective coatings and decorative surfaces. This practical roughness sets sherardizing apart from other zinc coating processes. At the same time, zinc diffusion creates a very uniform surface, even on complex geometric workpieces with cavities.

Coating materials in thermal spraying are various metal alloys or hard metals in the form of powder or wire. They are melted or fused and accelerated onto the component to be coated. Components can be, for example, drive shaft bearings and turbine and compressor rotors. Thermal spraying is particularly suitable for restoring the geometry and function of worn components using our fast and flexible repair service. Thermally sprayed coatings with their surface hardness give excellent wear protection. Through the targeted combination of materials and coatings, further durability and excellent functionalities are achieved.

When the coating to be applied has to be especially thin, the best results are achieved in the vacuum. We control the chemical reactions and reduce impurities to a minimum. After all, extremely fine coatings can reach their potential only with a high degree of purity. Our atomically anchored nanolayers are based on two advanced vacuum coating processes: Via electric arc (PVD process) metal is vapourised, ionised and then hurled onto the workpiece in an electric field. Reactive gases make it easy to create surfaces such as carbides, oxides or nitrides. Plasma Enhanced Chemical Vapour Deposition (PECVD) enables gaseous substances to be deposited on the substrate at less than 200 °C. This technology is ideal for extremely hard “diamond-like carbon” coatings. The most important properties of the vacuum coatings are non-stick properties, wear and corrosion protection, protection against cold welding and, in the field of medical technology, biocompatibility and hypo-allergenicity.

Wet painting is used to apply a surface protection coat to materials that are both electrically conductive and non-conductive. This technology uses conventional solvent-based PUR paints, solvent-free water-based hydro paints or VOC-compliant high-solidity paints, which – due to their high proportion of solids – have a significantly lower solvent content compared wto conventional paints. Wet painting allows the creation of attractive surfaces on virtually all substrates. Almost all options regarding color hues, structure and effect are possible.

The zinc flake finishing process is non-electrolytic. Techniques such as dip-spinning, spraying, dip coating or wet painting apply extremely corrosion-resistant zinc flake coatings. In contrast to other finishes, they permanently prevent damage caused by hydrogen embrittlement. Our sophisticated coating processes are ideal for complex shapes and bulk solids. Zinc flake coatings are used throughout the world in the automotive and construction industries as cathodic anti-corrosion coatings. In combination with post-treated thin organic or inorganic coatings, these can also provide colour, chemical resistance, low electrical conductivity, and bolting properties. If required, relubrication or screw locking is also possible.


get in touch interested in our technologies? please contact us...

Viviane Kettermann-Fernandes
Research & Development