Building galvanic materials, speaks to what are building galvanic materials and why building galvanic materials.
This is when different metals come into contact in the presence of moisture or some other conducting medium, electric current flows between them. Such metal pairs or galvanic couples, form the basis, for example for the storage of energy in batteries.
In building construction, galvanic couples are important for the manner in which the exchange of electrons affects the corrosion rates of the metals involved. This phenomenon that, if applied properly can be used to positive effect or, if ignored can lead to the premature deterioration of critical building components.
In any galvanic couple, the metal donating electrons, called the anode, experiences an accelerated rate of corrosion and conversely the metal receiving electrons is called the cathode, experiences corrosion at a reduced rate. This effect is relatively great for pairs of metals with large differences between their electromechanical potentials and proportionately smaller for those with lesser potential difference.
To facilitate the prediction of the corrosion potential of metal pairs, metals may be listed in galvanic series, that is, in order of their of their relative electrochemical potential with the most anodic or active metals at one end of the list and the most cathodic, noble or passive ones at the other.
Most Anodic or Active TO Most Cathodic or Noble
Zinc Aluminum Cadium Steel, Iron Aluminum bronze Naval brass, Yellow brass, Red brass Tin Copper Lead-tin solder Admiralty brass, Aluminum brass Manganese bronze, Silicone bronze, Tin Bronze Types 410 and 416 stainless steel Nickel Silver High copper content nickel copper alloys Lead Nickel aluminum bronze Nickel Silver Monel, high nickel content nickel copper alloys Types 304 and 316 stainless steel Titanium
Metal pairs positioned far apart in the series have greater corrosion potential than pairs closer to each other. Any number of galvanic series can be compiled for a group of metals in different conducting mediums and under different environmental conditions. For building construction a galvanic series based on metals immersed in flowing sea water is used.
Any metal listed higher in the series behaves as the anode when paired with any other metal listed lower in the series, which behaves as the cathode. Furthermore, in any such galvanic couple, the anode experiences accelerated corrosion, while the cathode’s rate of corrosion is reduced.