The classical chrome-plating in the layer system of copper, nickel and chrome not only offers a timeless decorative aspect but also high resistance against wear and corrosion. Appropriate mechanical pretreatments (grinding, polishing, glass bead blasting) produce mirror-bright but matt finishings with different gloss levels and structures.
Tin surfaces are proving themselves in electrical engineering and electronics, especially because of good conductivity and solderability.
Surfaces with precious metal coatings of gold and platinum obviously are high-quality surfaces. They are highly resistant to tarnishings and chemical attacks. In addition to purely technical application, they are also famous in prestigious areas. Precious metal coatings are used for matt, textured or high-gloss surfaces.
- The silver-coating is applied as a decorative and functional decorative layer. Silver-plated surfaces have a much better reflection than chrome-plated ones.
- The gold-coating produces decorative layers of high purity of gold (24 kt), about 0,1 to a maximum of 5 µm thick.
- The platinum-coating adds hardness and wear resistance to the extraordinary properties of precious metals.
For black oxide finishings a dense, black and shiny adhesive layer of iron oxide is produced. This is done by immersion into sodium hydroxide solvent of approx. 140 degrees Celsius and oxidizing agents. By the following immersion in oil the deep black gloss of the metal surface is emphasized and a good protection from corrosion is achieved.
Black chrome fulfills the highest requirements for low-wear, decorative and deep black surfaces. Low reflection and maximum absorption properties make black chrome particularly interesting e. g. for optical, photographic, laser and solar technology. It can produce similar structures as chrome-plating delivering all sorts of surfaces: matt finished, polished, with smoothing marks, or high gloss finish.
Zinc-plating as a low cost method with an attractive decorative effect provides corrosion protection for all steel parts. To increase corrosion protection and to achieve a better metal surface result the material is plated after galvanizing (blue, colorless, yellow or black). Trends point towards RoHS compliant chromium-free chromate coatings, which are already implemented today in the field of blue chromate.
During phosphatizing a layer of phosphate forms on the metal surface. It consists of a fine, crystalline salt layer of metal phosphates and firmly connects with the metal. A phosphate layer can be used as pretreatment for subsequent coating, e. g. powder coating. By immersion in oil or fat the corrosion protection is greatly improved, and the phosphated steel parts also have good sliding properties.