A Study on Corrosion Inhibition Effects Based on CS-NR Application Results on Leakage Accidents of Sprinkler Copper Pipes

Copper has better corrosion resistance than iron and good physical and chemical properties, including high electrical and heat conductivities. Therefore, it is widely used in various industrial applications. However, pitting corrosion occurs in the copper pipe of the sprinkler due to the oxygen concentration of the cell by the deposition of foreign substances on the inner side of the copper pipe, and leakage often occurs in the copper pipe due to the formation of shot holes. In this study, when a copper plate was submerged in a 3% NaCl solution for 10 days and the effects of the addition of CS-NR (6, 8, and 10 g) on corrosion protection were investigated by observing the surface conditions of the test specimen using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis by map the SEM results. The surface of the test specimen immerged only in the 3% NaCl solution without the addition of CS-NR exhibited pitting corrosion due to chloride ions. However, with the addition of CS-NR, pitting corrosion was not observed at the surface, regardless of the amount of CS-NR added. Furthermore, the addition of 8 g (8 × 10<sup>3</sup> ppm) of CS-NR resulted in the best corrosion resistance against pitting corrosion because the amount of oxygen and silicon that formed the protective film revealed an optimal mixed ratio as compared with 6 and 10 g of CS-NR.