The seminar covered in the topics of Corrosion Theory, Simplified Galvanic Series
, Types and Factors of Corrosion, Cathodic Protection Systems and its International Standards.
The farther apart two metals are on the galvanic series
chart, the faster the active (anode) metal will corrode in the presence of the electrolyte.
Table 1 presents a galvanic series of selected metals common in construction.
Table 1 Galvanic Series of Selected Metals Common in Construction Anodic, Active (Read down) Magnesium Zinc Aluminum Mild Steel Wrought Iron Gray Iron and Ductile Iron Lead Tin Brass Copper Stainless Steel, Type 304 Stainless Steel, Type 316 Titanium Silver Gold Platinum (Read up) Cathodic, Noble
In the presence of salt water, electrochemical reactions between the two metals result in corrosion of the metal which is less-noble (more anodic), ranked by its position on a galvanic series
. In the case of aluminum and steel, varying grades and coatings--and varying surface areas--can mean varying results.
Similarly, avoid threaded joints for materials that are far apart in the galvanic series.
Table 1: Galvanic series shows varying potential of metals in seawater.
In the galvanic series
of metals, opposites could likely form an electric current if they come in contact.
An experimentally measured galvanic series is presented in Table 1.
Galvanic Series in Seawater at 24[degrees]C Material Electrode Potential, Volts * Graphite +0.250 Platinum +0.150 Zirconium -0.040 Stainless Steel, 304, passive -0.080 Silver -0.130 Nickel -0.200 Lead -0.210 Tin -0.320 Naval Brass -0.340 Copper -0.360 Stainless Steel, 304, active -0.530 Carbon Steel -0.610 Cadmium -0.710 Aluminum -0.790 Zinc -1.030 Magnesium -1.480 * Potential vs.
The potential of metals for galvanically driven corrosion is ranked using the galvanic series
, and the most widely published of these is for metals in seawater.