Effect of Ti on the corrosion behaviour of as-cast Fe–17Cr ferritic stainless steel

ABSTRACT

The effect of Ti addition on the microstructure and corrosion resistance of the as-cast Ti-stabilised Fe–17Cr ferritic stainless steels was investigated by optical microscopy, scanning electron microscopy, X-ray diffraction and energy-dispersive spectrometer. The corrosion behaviour of the as-cast Fe–17Cr ferritic stainless steel in 10 wt-% HNO₃ and 10 wt-% NaOH solutions was examined by using potentiodynamic polarisation curves and electrochemical impedance spectroscopy. After Ti addition from 0.06 to 0.26 wt-%, the size of TiN precipitates in the as-cast Fe–17Cr ferritic stainless steel increases and the corrosion resistance is improved in 10 wt-% HNO₃ and 10 wt-% NaOH solutions, especially in 10 wt-% HNO₃ solution. Mott–Schottky curves demonstrate that the addition of Ti can inhibit the decomposition of the passive film, which can improve corrosion resistance.

KEYWORDS:

• Ferritic stainless steel
• TiN
• corrosion resistance
• polarisation
• EIS

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [Grant Number 51571081].