Estimation of the performances of creatine and creatinine as eco-friendly corrosion inhibitors for copper in sodium hydroxide solution

The performances of two naturally occurring compounds, namely creatine and creatinine as ecologically friendly inhibitors versus the corrosion of copper in 0.5 M NaOH solution were inspected using chemical, electrochemical and microscopic techniques. The acquired outcomes designated that the inhibition efficiencies (% IEs) of the investigated compounds were increased with increasing their concentrations and decreased with rising temperature. The investigated compounds were served as mixed inhibitors with cathodic seniority. The inhibition performances were interpreted on the basis of their strong adsorption on the copper surface and the adsorption process obeyed Langmuir adsorption isotherm. Thermodynamic and kinetic parameters were evaluated and debated that prove the physical adsorption nature of the investigated compounds. The kinetics of copper corrosion and its inhibition by creatine and creatinine were studied. Throughout all applied techniques, the obtained outcomes were in well agreement with each others which confirmed that the examined compounds acted as excellent inhibitors for copper corrosion in 0.5 M NaOH solution and the values of % IEs of creatine were slightly higher than those acquired for creatinine at all the studied concentrations.