Nickel plating provides a high resistance to acids and alkalis and can be recognised by a slightly "yellowish" appearance compared with chrome plated versions. Chrome plating also provides additional protection due to its greater hardness and can be visually recognised by its clear mirror-finish. However, the surface gloss can only be controlled within certain limits (surface gloss vs. durability) and it always depends on the existing surface structure of the substrate material. Essentially, the surface gloss depends on the degree of gloss of the underlying nickel plating. Normally, the external components of HEROSE valves are treated. However, this does not mean that the internal components can be treated if required.
In order to ensure durable plating of the surface, it is especially important that the components are specially cleaned prior to the actual plating. Because of the special cleaning process, deoxidisation and thorough rinsing several times in completely desalinated water, the components are activated ad prepared for the electroplating process.

Process description
Electroplating refers to processed for the electrochemical deposit of metallic coatings onto metallic or non-metallic substrates. Electro-crystallisation is carried out in an aqueous solution of metal salts, either by the external application of direct current (method I), or without the use of current by means of the reaction of the metal ions with a reducing agent (method II). The components of HEROSE safety valves are given a high-gloss nickel plating by means of method I. Although methods which do not use current, e.g. chemical nickel, plate all surfaces which are wetted by the electrolyte, they do not provide the required degree of gloss.
With chrome plated components, an additional chrome plating process is carried out after electroplating with nickel as described above. The depositing of chrome onto the component is once again carried out by means of direct current from an external source.