Effects of environmental factors on corrosion behavior of high-silicon cast iron in Shanxi soil medium

High-silicon cast iron has excellent corrosion resistance in some specific medium. But the effects of pH value, chloride concentration and soil moisture content on corrosion behavior are still unknown. This study aims to provide reference for the application of high-silicon cast iron in different environments.

Electrochemical impedance spectroscopy and potentiodynamic polarization curves were used to investigate the corrosion mechanism and rate. The morphology was observed by scanning electron microscopy. The chemical compositions of the corrosion products were detected by energy-dispersive spectroscopy and X-ray diffraction.

When the solution is acidic, the corrosion of high-silicon cast iron is more serious. When the chloride concentration is 0.1 per cent, the corrosion rate of high-silicon cast iron is the largest. A passive film is formed on the surface to prevent the corrosion reaction with the increasing of chloride concentration. The corrosion rate is the largest when water content is 15 per cent, and the corrosion is the lightest when water content is 30 per cent.

This study provides support for the selection of high-silicon cast iron as grounded material.