Effect of temperature and erosion on pitting corrosion of X100 steel in aqueous silica slurries containing bicarbonate and chloride content

• At open circuit potential, pitting corrosion was observed at 35 °C but not at 22 °C.
• By increasing the electrolyte temperature the pitting potential decreases.
• By increasing the electrolyte temperature the pitting current densities increases.
• Circular or square shapes of the pit mouths convert to elliptical shapes.

The effect of temperature on erosion-enhance pitting corrosion behavior of X100 steel has been investigated. Tests were performed at two temperatures with the help of open circuit potential (OCP), potentiodynamic polarization scan and electrochemical frequency modulation. A heating plate was used to change and maintain the temperature of electrolyte during electrochemical tests. During zero and low erosion rates, the OCP decreases with increase of temperature. In contrast, during high erosion rate, the OCP first decrease and then increases. The few higher values than the normal values of 2 and 3, both causality factors gave mainly lower values during pitting corrosion.

With silica slurry speed of 3.6 m/s at 22 °C, good shaped pits like that of stainless steel were observed. Clear erosion marks and pits were observed at 35 °C.Figure optionsDownload as PowerPoint slide