Abstract
The influence of silicon and manganese on the electrochemical and corrosion behavior of a high purity austenitic 14Cr/14Ni-balance Fe alloy has been studied. Over the composition range 50–41, 500 ppm Si, no effect was observed on the kinetics of the anodic or cathodic partial processes. Addition of manganese over the range 5–26,300 ppm accelerates the anodic dissolution kinetics in the active range of potentials and also the steady-state corrosion rate in 1N̄ H2SO4 due to its influence on the kinetics of the cathodic partial process. The nature of this effect is analyzed according to electrode kinetic concepts from which it is shown that manganese changes the value of the electrode process transmission coefficient. Alloys containing manganese and silicon over large concentration ranges are extremely resistant to stress corrosion cracking in boiling 42 w/o MgCl2.