Effect of W and Ce additions on the electrochemical corrosion behaviour of 444-type ferritic stainless steel.

In order to achieve excellent heat resistance and corrosion resistance, high melting-point and rare earth elements were added to ferritic stainless steel. The effect of W and Ce addition in ferritic stainless steel on the corrosion resistance in 0.1 M NaOH solution was studied. Potentiodynamic polarisation curves indicated that W- and Ce-containing samples had lower corrosion rate and lower passive current density. The electrochemical impedance spectroscopy measurements revealed that W-Ce-containing samples had higher polarisation resistance values and thicker passive films. Capacitance analysis indicated that the semiconducting behaviour and the properties of passive film remain unchanged. The addition of W and Ce led to a decrease in donor and acceptor density, which improved the passive film stability. [ABSTRACT FROM AUTHOR]