THE EFFECT OF TEMPERATURE AND NA2SIF6 ADDITION ON PROPERTIES OF HARD CHROMIUM PLATING DEPOSITS ON FCD700 NODULAR CAST IRON SUBSTRATE

• Main Author: Monica, Mutiara
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47346
• Institution: Institut Teknologi Bandung

Hard chromium plating is widely applied on mechanical components due to the deposited layer’s high hardness and wear resistance. An example of hard chromium plating application is a piston ring. In the process of manufacturing a piston ring, a substrate with high ductility but high hardness on the surface is required. To obtain an optimum layer quality, parameter optimization is necessary. In this study, plating was carried out using the hard chromium plating method with solution temperature variations (45, 50 and 55 oC) and variations of the addition of Na2SiF6 catalyst (0, 1 and 2 g/L). Other parameters such as 250 g/L chromic acid concentration, addition of 2.5 g/L H2SO4 catalyst, 80A/ dm2 current density, 1 hour coating duration and 150 rpm agitation speed were kept constant. The results showed that the maximum layer hardness was 846 ± 72 VHN which was achieved at a solution temperature of 50 ± 2 °C with 1g/L of Na2SiF6. The maximum cathodic current efficiency and layer thickness was 20.14 ± 0.64 % and 142.77 ± 11,65 ?m which was achieved at a solution temperature of 45 ± 2° C with 1g/L of Na2SiF6. The XRD results revealed that there was a change in the lattice parameter values in all specimens that resulted in the distortion of the crystal lattice which contributed to an increased of microstrain. In the end, chromium layer hardness was increased.