Commercially available inhibitors were successfully investigated for their effectiveness in reducing the corrosion susceptibility of the turbo expander and steam/gas turbine industry alloys. However, due to the fact that the power generating system is complex and consists of a multi-alloy system, the investigation was expanded to study the corrosion behavior and stress corrosion susceptibility of other alloys such as, copper, brass C36000, C69300, red brass C83600, and nickel plated-copper in the presence of these inhibitors. Electrochemical behavior (cyclic polarization and EIS) of these alloys in a 200 ppm chloride solution with different percentages of inhibitor showed significant improvement in passivity, and breakdown potentials. The data acquired from electrochemical tests showed that inhibitor adsorption to the alloy surfaces fits with the Langmuir adsorption isotherm; the enthalpy of adsorption is about -10 to -16 kJ/mol, suggesting that this chemical compound provides physisorption to the alloy surfaces. During testing per ASTM(1) standards G44 and G38, no susceptibility to environmentally-assisted cracking was observed upon the addition of 10% inhibitor.

Subject
Electrochemical impedance spectroscopy, Inhibitor performance, Metal surfaces, Adsorption, Adsorption isotherms, Volatile corrosion inhibitors, Copper alloys, Chemical inhibition, Corrosion inhibitors, Corrosion protection, Brass, Alloys, Stress corrosion cracking
Keywords:
VCI, SCC, Critical pitting temperature, steam turbine, Volatile corrosion inhibitors, physisorption, brass and copper alloys
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2013
Association for Materials Protection and Performance (AMPP)
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