Corrosion of metal parts in the power plant

Abstract

The AISI 304 (X5CrNi19‐10) stainless steel is widely used for the production of various metal parts in power plants. A procedure for testing the influence of the dust from a power plant on resistance to general and pitting corrosion of the AISI 304 stainless steel is developed and performed. The quantitative (XRD method) and qualitative (Fourier–transform infrared spectroscopy [FTIR] method) composition of the dust present in the power plant is determined. Applying the Mott–Schottky method, the properties of the passive layer are analyzed, while a degree of chromium depletion of the grain boundary is determined by the electrochemical potentiokinetic reactivation method with double loop method. Values of polarization resistance (linear polarization resistance and electrochemical impedance spectroscopy methods) and the corrosion current density (polarization measurements) indicate that the stainless steel has a higher resistance to general corrosion in the dust solutions than in the etalon solution. Also, based on the measured value of the pitting potential (Epit) and the difference between the values of the pitting potential and the corrosion potential (Epit – Ecorr), it can be seen that stainless steel has a higher resistance to localized types of corrosion, such as pitting corrosion, in dust solutions than in the etalon solution.