The effect of ɳ-Ni3Ti precipitates and reversed austenite on the passive film stability of nickel-rich Custom 465 steel.

• The microstructure of Nickel-rich Custom 465 steel is significantly changed by various tempering temperatures. • Passive film stability first reduces and then increases with increasing tempering temperatures. • The Volta potential of the interface between nanoscale ɳ-Ni 3 Ti and the matrix is the lowest. • The Volta potential of reversed austenite is higher than that of martensite. The multiple effects of ɳ-Ni 3 Ti precipitates and reversed austenite on the passive film stability of nickel-rich Custom 465 steel were studied. The results showed that with an increase in tempering temperature, the η-Ni 3 Ti precipitates gradually coarsened. The Volta potential of the ɳ-Ni 3 Ti/matrix interface was approximately 30 mV lower than that of the precipitates, which decreased the passive film stability. The volume of reversed austenite gradually increased at higher tempering temperatures. The Volta potential of the reversed austenite was 14 mV higher than that of the martensite, which enhanced the passive film stability and slightly increased the pitting corrosion resistance. [ABSTRACT FROM AUTHOR]