Effects of flow variations 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 flow variations on the galvanic corrosion of the copper/AISI 304 stainless steel pair in a concentrated lithium bromide solution were investigated in a hydraulic circuit applying different flow steps and using a zero-resistance ammeter (ZRA). The flow steps consist in applying a flow rate for sixty minutes after leaving the system under stagnant conditions for another sixty minutes; this procedure is repeated during eight hours. The magnitude of the steps is different depending on the flow regime studied, ranging from a Reynolds number of 633 to 5066. Results show that, when a flow step is applied, the galvanic current density increases and the galvanic potential shifts towards more negative values. However, with time, this increase in the galvanic current density is lower, reaching its lowest value in the last hour of the experiment at a Reynolds number of 5066. Thus, although the corrosion rate increases as Reynolds number increases, the protective corrosion products are generated earlier on the copper surface. © 2012 by ESG.