PENGARUH ENERGI AKTIVASI LOGAM PELAPIS TERHADAP KETEBALAN DAN LAJU KOROSI PLATING

Abstract

This study aims to study the effect of the activation energy gradient (∆G) of metals on the thickness and corrosion rate of Ni layers; Cr, and Ni-Cr. The layer is obtained through the Ni electroplating process; Cr, and Ni-Cr in carbon steel specimens using a variation of current strength of 1.25; 1.5 and 1.75 Ampere at constant stress and coating time (15 minutes). Nickel plating is obtained in the electric layer process using a watt's bath electrolyte solution in a mixture of 150 g / l NiSO4, 30 g / l NH4Cl, 30 g / l H3BO3 with a temperature of 25-35 oC, pH around 4-6, air agitation, Chromium plating using anode in the form of an alloy of Pb (lead) and Sn (antimony) rods, a solution in the form of an electrolyte mixture of 300 g / l CrO3, 3 g / l H2SO4 in working temperature of 40–55 oC, pH around 0.4 - 0.5 and air agitation. Corrosion thickness was observed using an optical microscope at 200 X magnification while the corrosion rate of observation was carried out based on the method of resistance polarization in the medium of 0.9% Sodium Chlorid Solution. The results showed that, in the same treatment, the thickness of the layer increased in increasing current strength, slower chromium than nickel layer and Nickel-Chromium layer. Sequential thickness of layers is obtained for Ni: 51, Cr: 39 layers, while corrosion rates occur at 1.75 A current in nickel layer 0.0017 mm / year; Chromium layer, 0.0077 mm /year and Nickel-Chromium layer 0.0231 mm / year