Abstract
It is one of the most difficult problems that the city water becomes red owing to the degradation of scale formed on the inner surface of water pipe.
In this paper, the role of some inorganic corrosion inhibitors such as PO43-, SO42- and Ca(OH)2 was studied electrochemically. Iron plate was immersed in the test water containing inhibitors of various concentrations. Weight loss measurement was also made.
It was shown that the phosphate inhibitors (sodium-hexameta-phosphate) was the most effective among the compounds tested presently.
The influence of frequency and of immersion time on the impedance change was also studied to see the variation of the surface state of iron probe.
