The chroming process
Nickel is used in many applications: the main one is for decoration and as a pre-layer for chromium. With the galvanization procedure there are 2 ways: the electrolysis way and the catalytic way. Electrolytic nickel is mostly used for the decorative market under chromium as a pre-layer to protect from corrosion;
The recipe to apply nickel through the electrolytic procedure is centuries old; we call it the” Watts Nickel”. The main components here are: nickel sulphate, nickel chloride and boric acid. In order to obtain the brilliance people add organic components.
Copper is one of the first metals that have been precipitated by the human race. Nowadays its main application lies with PCB and the gravure printing industry. One uses copper baths where sulphuric acid as well as cyanide are added. These acid baths possess a formidable asset: the one of filling up scratches, thanks mainly to the presence of the organic components within. It is for this property that the decorative market uses it. Next to this, acid baths with copper are used in the gravure printing industry and in order to restore oldtimers.
G&R uses copper acid baths in order to restore spare parts made of steel. Copper baths where cyanide is added are used mostly with Aluminium en Zamak.
Chromium is the most well known metal to be precipitated. It is used in bathrooms and sanitary appliances, with the automobile industry, bicycles, motors, engraving and so on. It is mostly used in order to add an extra shine to the metal. Chromium does not possess in itself any shining property; the glow comes from the underlying nickel. Chromium can be polished extremely well. If the layer is applied too thick on the nickel underneath, then, a mouse-grey layer will appear. In order to obtain a beautiful shine a layer of 3-5µm is sufficient. Chromium baths are composed with very simple elements; they mostly consist of chromic acid in which sulphuric acid has been added as a catalyst. The chromium bath extracts the chromium from the acid; the anodes consist of lead which liberates only the electrons needed.
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