It is well known that resistance against pitting corrosion decreases as temperature increases. The concept of critical pitting temperature (CPT) was introduced by Brigham as a temperature below which the steel will not pit regardless of potential and exposure time(1). Duplex stainless steels (DSS) are iron based alloys that their usage has been limited to temperatures below which pitting corrosion occurs. To encompass a higher temperature application and improve the pitting resistance of stainless steels in halide media, using inorganic-based corrosion inhibitors has been recommended (2-4). In the 1960s, Uhlig and Gilman(5), were reported Nitrate (NO3 –) inhibition of pitting in Fe-Cr-Ni alloys. The positive effect of nitrate ion on CPT of a high-entropy alloy has been reported by Chou and coworkers(3).

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