The thick chromium-plating process has the aim of creating hard and opaque and wear resistant hard chrome deposits, with thicknesses greater than 1μm up to even 100 μm directly on the object to be coated without interposing layers of copper or nickel.
The objects to be coated with hard chromium are treated in a solution of chromium salts and the metallic chrome coating is obtained by an electrochemical reduction process.
The features that determine the technical and industrial relevance of chrome coatings are:
- high hardness
- low friction coefficient
- suitability for uses in severe tribological conditions
- good mechanical workability
- high chemical and thermal resistancea
The hard chrome deposits are featured by high hardness and wear resistance and it is thanks to these peculiarities that are used in various sectors. The hardness can varies between 900-1000 Hv.
The corrosion resistance of a hard chrome deposit depends on the thickness deposited, the adhesion of the deposit and the micro-cracking.
This micro-cracked structure is responsible for the high hardness of deposits.
Oxidizing or reducing agents have little effect on chromium, however it is attacked by hydrochloric acid and chlorides in general, moderately by sulfuric and nitric acid.
The chrome deposit can be opaque or glossy depending on the preparation of the pre-coating piece (sandblasting, polishing). Therefore the roughness can vary according to the customer’s requests. Ra can be obtained between 0.2-2.0
The electroplated chromium layer is not uniform in its distribution, in particular there will be areas such as edges or points where there will be a very marked deposition, while in the holes and in the undercuts the deposition will be almost none.
We can coat the following materials after appropriate preparation and without intermediate layers:
- Aluminum and its alloys after special preparation
- Acciai al carbonio anche trattati termicamente
- Carbon steels also heat treated
- Cast iron after sandblasting
- Copper and its alloys
The maximum dimensions of the parts that we can work are 1600x1100x300
Possibility of de-hydrogenation and / or lubrication with emulsifiable oils.