EFFECT OF MINOR RUTHENIUM ADDITIONS ON THE CORROSION BEHAVIOR OF DUPLEX STAINLESS-STEELS IN SULFURIC-ACID

The influence of minor ruthenium additions on the corrosion of three g roups of duplex stainless steels has been studied. The tests were carr ied out at various temperatures and at a number of different concentra tions of sulfuric acid. Mass loss test results were used to construct isocorrosion curves and to determine conditions of spontaneous passiva tion and active dissolution. Electrochemical measurements were employe d to determine the effect of ruthenium on various important corrosion parameters. Conclusions have been drawn about the mechanisms responsib le for the increased corrosion resistance of the cathodically modified alloys and some guidelines for future investigations in this field ar e proposed.