Moisture content and chloride ion effect on the corrosion behavior of fitting brass (gate valves) used as a connection of PVC’s conduits in aggressive sandy soil

The corrosion of four brasses EC1 and EC2 of ( α + β ) brass type while EC3 and EC4 are of α -brass type in the aggressive sandy soil collected in a suburban area of Essouira Morocco was studied. The original soil was characterized, and modified by adding the chloride ions or by increasing its moisture content. The corrosion behavior of these brasses in soil was investigated at ambient temperature using various electrochemical methods. The different alloy surfaces were examined by scanning electron microscopy, whereas the chemical composition was determined by EDS analysis. EIS measurements indicated that the corrosion rate of all brasses series increases with increasing the moisture content of the studied soil up to critical limit (30 wt%), then it starts to decrease with further increase of moisture content. It was found that the chemical composition of brass influences the corrosion rate, especially the presence of iron, Nickel and Arsenic. Furthermore, EC3 is always the most resistant among the other alloy even in a very aggressive environment containing the chloride ions with a concentration of 2%.