Hard chromium plating under reduced pressure

The use of the reduced pressure method in hard chromium plating is investigated. The properties of deposited coatings are tested with various methods. The main object of the work is to study the corrosion resistance and the porosity of the coating. Other properties like the hardness, surface profiles and the microstructure of the coating are also investigated. It is shown that hard chromium coatings having the best properties are obtained by the reduced pressure method by using the SRHS-electrolyte at high bath temperatures (59 - 61 °C) with a low current density (about 30 A/dm2). The chromium coatings deposited in these conditions have a very good corrosion resistance and a low porosity. Further, the current efficiency of coating is decreased as compared with chromium coatings deposited with the conventional plating methods.