Galvanic Corrosion Behavior of Electroless Nickel Coating in Al-Zubare Harbor-Water


Electrode potentials in AL-Zubare harbor water (South -Gas Company),of 23.88 ohm-cm at 20oC were reported for 26 metals and alloys includingvalues for electroless nickels that signify a greater passivity than steel. Thelarge potential difference between steel and electroless nickel predicts severegalvanic corrosion, which was confirmed by weight loss data for coupled steeland electroless nickel electrodes immersed in AL-Zubare Harbor water(South -Gas Company, 23.88 ohm-cm at 20oC) .Changes in the phosphorouscontent in the range of 7.10 to 12.45 percent had only a slight effect on theelectrode potential of electroless nickel.This study indicates the beneficial use of electroless nickel coating is morepassive than other (metals and alloys) and that galvanic corrosion of activemetals such as steel can be severe .