Laboratory Studies of Galvanic Corrosion: III. Effect of Velocity in NaCl and Substitute Ocean Water

Abstract

The galvanic corrosion behavior of 4340 steel coupled to Type 304 stainless steel, Cu, Ti-6AI-4V, Al 2024, Al 6061, and zinc has been studied in 3.5% NaCl and ASTM substitute ocean water as a function of velocity using a rotating galvanic couple electrode holder. For steel coupled to Type 304 stainless steel, Cu or Ti, the galvanic current generally increases proportional to the square root of the rotation speed in both media. The increase is, however, smaller in the substitute ocean water. For couples involving Al alloys and Zn, the galvanic current has a more complicated dependence on velocity in substitute ocean water than in 3.5% NaCl.