#Product Trends
OMG filter pumps and GALVITEK experience
Chromium and Nickel Plating Processes
Chromium and Nickel are the most important metals in galvanic deposition.
The nickel and chromium plating processes are widely used both in the mechanical field and in the sectors such as furniture, taps, aeronautics, naval sector, restoration of vintage motorcycles / cars / bicycles ...
Nickel plating is one of the most used galvanic processes because it covers a great variety of applications. It allows to obtain objects with excellent decorative and aesthetic characteristics, but it is also applied for technical purposes as corrosion and wear resistance, weldability, magnetic properties and for the electroforming.
The decorative nickel plating provides very smooth, leveled and mirror-like bright coatings, also characterized by good corrosion protection properties.
The functional nickel coatings are specifically applied to modify and improve surface characteristics such as hardness, corrosion and wear resistance and magnetic properties. The aesthetic appearance of these coatings is appreciable, but mechanical properties represent the requirements to be controlled.
Chromium is used in order to exploit its characteristics of stainless, gloss and corrosion resistance. The Cr coating is used to ennoble less expensive and easier working materials such as steel and plastic. This coating has a high reflective power and a typical bluish white color, which is maintained over the time thanks to the Cr intrinsic features such as opacification, abrasion and scratching resistance.
The definition "chromium plating" is used to identify synthetically the traditional electroplating sequence of copper (Cu), nickel (Ni) and chromium (Cr) or, more simply, of Ni and Cr.
The Ni sub layer has become crucial because it protects the substrate from corrosion, for its particular white color given to the Cr and for the corrosion resistence received , in turn, from the subsequent Cr layer.
Stainless steel is the only material that can be chromed directly, although, in some cases, it is preferable to apply anyway a Ni pre-layer.
Until 1975 only hexavalent Cr baths were used; later, trivalent chromium plating baths were introduced: they offer diffferent coloured deposits, from pewter to metallic white, similar but not identical to the typical color of hexavalent Cr deposits. These baths are gradually gaining momentum also because of the restrictive laws regulating the use of hexavalent Cr, due to its carcinogenic properties.
A very important aspect in Cr3+ baths is the control of contamination caused by foreign metals. In fact, trivalent Cr baths are very sensitive to these pollutants which compromise their penetrating and hiding powers and their caratheristic color tone . The most used method to remove foreign metal contamination is to treat the bath with ion exchange resins (please, see our next Newsletter about RESIN FILTER C24).
Nickel and Chromium platings are both composed by aggressive and corrosive electrolytic solutions; OMG filter pumps are used in the mentioned galvanic processes since they are built using anticorrosive or highly protected materials to withstand acids and dangerous filtering-liquid components
The customer we would like to introduce in the newsletter, selected the filter pump model TE25 (effective capacity: 25 000 l / h, capacity: 56 000 l / h), correctly sized for its production needs. During the period 2004-2018 the client bought 5 machines TE25 model.
The peculiarity of the filter pumps - TE series, which also makes them aesthetically original and recognizable in the target market, is represented by a solid and blue steel filtering tank. This tank has an internal coating made of a protective elastomer (ebonite) and contains the filtering block which is systematically assembled by the succession of Noryl filtering panel, filtering paper, PP filtering frame.
This technical solution has proved successful in guaranteeing high filtration standards (<1 micron), because it avoids the deformation of the circolar filtering inserts, which causes inefficiencies in the function of retaining unwanted substances.
