Chrome plating

Processes

Chrome plating

Chrome plating is a proven, extremely versatile coating process that stands out because of its extensive list of positive properties. It is highly decorative, corrosion resistant, hydrophobic, and abrasion and wear resistant. Its hardness and resistance to oxidising media are especially noteworthy.

Chromium also plays a major role as a partner in multi-layer coating systems, underscoring its decorative or functional properties even more. Chrome layers are used in countless applications and are currently almost impossible to replace for many products with all of their advantages.

Inquiry Technical data

Advantage

Advantages at a glance

Corrosion - Surface protects.
The natural state of metals is an oxide. In the metalworks the oxide is extracted by using oxygen and energy and the pure metal is obtained. However, the metal is “predestined” to return to its original state at exposure to oxygen and water. And the less precious the metal is, the faster it happens. That is corrosion.

Surface technology slows down or prevents this corrosion process. Protection against corrosion through innovative surface technology increases service-life and thus raises the value of the product or structural component. Collini provides numerous possibilities to combat corrosion.

By means of electro-plating, structural components can be protected against corrosion with suitable metal coatings.

Powder coatings form impenetrable barriers against oxygen and water and thus protecting the underlying structure.

Hot-dip galvanising protects steel parts by specifically inducing the corrosion process on the zinc surface. And only there!
Design - Surface creates.
Collini surface technology makes it possible to create products in such a way that they appeal to the varying aesthetic requirements and wishes of consumers. Design is more than the form and functionality of an object. In many cases, it is the aesthetics that adds to the value. The look, colour or structure of identical materials can be changed through different surfaces.

Powder coatings with its almost infinite possibilities in terms of colouring, degrees of glossiness and structures give products their true character. It is irrelevant whether it concerns machine cladding, vehicle components or architectural design elements.

High quality metal surfaces can be created with electroplating, the properties of which distinguish it clearly from that of the base material. Hence, products are refined and the required effects in finish and structure of the respective product
are created.

Hot-dip galvanised structural components with its crystalsilver surfaces are, besides the corrosion protection, often specifically included as design elements.
Tribology - Surface prevents wear.

Collini intensively deals with tribology: in other words, how friction and wear can be reduced or the lubrication between structural components can be improved. Because these factors are directly affected by the choice of the material, the surface coating and the surface topography.

Specially developed alloys and coating systems – Collini surfaces – reduce for example the energy input through the reduction in friction, increase the service life of bearing materials, plug contacts or improve the service performance of sliding contacts. Thereby the respective structural component can be manufactured from inexpensive basic materials. Then its required functionality – lower friction resistance or wear – is created with the coating system. By reducing friction and wear, energy and raw material resources are preserved and the service-life of products is increased. This is how Tribology contributes significantly to sustainability.

Technical data

	Chromium
Processes	Chromium salt-based electrolytic deposition
Coating colour	bluish white
Base material	Steel, aluminium, non-ferrous metals, die-cast zinc
Corrosion protection	Depends on process
Hardness	from 300 to 600 HV, hard chromium 800 to 1000 HV
Temperature resistance	up to 600 °C
System technology	Frame
Conformity	CrVI free
Execution	Glossy chromium, matt chromium, black chromium, hard chromium
From our R&D	GGHG (Graphit-Gray-High-Gloss)
Protective properties	Resistant to attack by diluted acids and most alkalis, water, air
Functional properties	Abrasion and wear resistant, hydrophobic, temperature resistant, glossy chromium: good tarnish resistance, black chromium: electrically conductive, good thermal conductivity, high temperature resistance (up to 600 ° C)
Decorative properties	Glossy chromium: permanent gloss, high reflectivity, black chromium: deep black, uniform colour, amorphous appearance
Special properties	The gloss of the chromium-plated workpiece is also determined by the underlying materials at low layer thicknesses.

Details

Typical components & applications

Typical components

Shaver handles, decorative furniture and household items, plug housing units, surface-mounted housing units, vehicle parts, machine parts, furniture fittings, window and door fittings, fastening components

Industrial applications

Consumer goods, electrical and industrial engineering, furniture industry, vehicle manufacturing, mechanical engineering, mining, oil and gas industry

Chrome process at Collini

Chrome plating

Chromium is a bluish-white, brittle metal that can be mechanically polished to a high gloss. A particularly important feature of chromium is its behaviour towards oxidising media. When treated with nitric acid or oxidising acid mixtures, chromium becomes passive. Atmospheric oxygen also causes passivity of the active chromium, which means that passive chromium is close to precious metals in terms of value. Chromium's known tarnish resistance and its good corrosion resistance are based on this passivity. Chromium is resistant to phosphoric acid, acetic acid, citric acid, tartaric acid and most other organic acids. Metallic chrome is resistant to dry air. It barely corrodes in humid air. Chromium is also resistant in alkaline media, as long as no strong oxidising conditions are present.

Glossy and matt chrome

Creation of glossy chrome is a highly decorative chrome process, and it is usually deposited on a glossy nickel layer. When the chrome layer is deposited over a pearl nickel process, the appearance of the underlying nickel layer is reproduced. The layer thicknesses are usually in the range of 0.25-0.5 µm. The wear resistance of the chrome layers is very good, but the material is brittle and therefore not ductile. They feature good reflectivity.

If a layer of nickel under the chrome is matt, then the workpiece will still be matt (matt chrome) after the (thin) glossy chrome plating. This kind of matt surface is desired in some cases and is then perceived as very high quality (semi-matt).

Black chrome

Black chrome is a decorative black surface. The black chrome layer is one of the few deep black surfaces that are electrically conductive. Some black chrome layers only have moderate abrasion resistance. This effect can be slightly improved by subsequent oiling. All nickel surfaces can be considered as a base for black chrome plating, and copper and steel can also be black chrome plated directly. Black chrome is highly oxygenated and coatings consist of chromium and chromium oxides, which means that they are not as mechanically resistant as gloss chrome coatings, for example. Black chrome is temperature resistant up to 500 °C. Black chrome coatings are primarily used in the measuring industry and in consumer electronics.

Hard chrome

Hard chrome is a time-tested, universal surface protection, which is deposited in an electrochemical process using insoluble anodes and high current densities in chromium acid-containing solutions. Virtually all standard base materials can be coated with different layer thicknesses depending on the expected mechanical or chemical stress required of the component.

Hard chrome coatings are used wherever a high level of hardness, temperature resistance, wear resistance and corrosion protection are required. In addition, they feature low friction and low adhesiveness; they are tarnish-resistant and harmless to health. These versatile advantages offered by hard chrome layers can be seen in all industrial production areas, and they represent a low-cost solution for various requirements.