Oxazole derivatives as corrosion inhibitors for 316L stainless steel in sulfamic acid solutions

Oxazole derivatives were investigated as corrosion inhibitors for 316L stainless steel (SS) in sulfamic acid (NH2HSO3) solutions by potentiodynamic polarization, electrochemical impedance spectroscopy, and electrochemical frequency modulation techniques. The results showed the variation in inhibition performance of the inhibitors with varying concentrations and temperatures. The maximum efficiency was found to be 91% at 2 × 10−4 M concentration of the inhibitors for the immersion period of 3 h. Langmuir was tested to describe the adsorption behavior of inhibitor on 316LSS surface. Potentiodynamic polarization study clearly revealed that these compounds act as mixed-type inhibitors. The results of the electrochemical impedance study showed a decrease in double layer capacitance and increase in charge transfer resistance. The results of various electrochemical techniques show good agreements with each other.