Influence of temperature and Reynolds number on the galvanic corrosion of the copper/AISI 304 stainless steel pair in lithium bromide using a zero-resistance ammeter

Abstract

[EN] The effects of temperature and Reynolds number (Re) on the galvanic corrosion of the copper (UNS C15710)/AISI 304 (UNS S30400) stainless steel pair in a concentrated lithium bromide (LiBr) solution was investigated in a hydraulic circuit using a zero-resistance ammeter. Results show that copper is the anode and that galvanic current density decreases with time because of the formation of a protective film. Initially, galvanic current density increases with Re; however, with time, differences decrease and this tendency is even reversed. As Re increases, greater quantities of corrosion products are initially produced and a thicker film is formed. The galvanic current density increases with temperature, suggesting that the films formed at lower temperatures are less defective and more resistant; however, at the highest flow rate, with time, the galvanic current density is lower at 75°C than at 50°C. This behavior is attributed to the quick and large formation of corrosion products at the highest flow and temperature. Statistical analysis proved that the effect of temperature on galvanic current density is more influential than the Re effect, and the variation induced by time is only significant during the first hours.