Galvanic Corrosion
Galvanic corrosion potential is a measure of how dissimilar metals will corrode when placed against each other in an assembly.
Galvanic corrosion potential is a measure of how dissimilar metals will corrode when placed against each other in an assembly. Metals close to one another on the chart generally do not have a strong effect on one another, but the farther apart any two metals are separated, the stronger the corroding effect on the one higher in the list. This list represents the potential available to promote a corrosive reaction, however the actual corrosion in each application is difficult to predict. Typically, the presence of an electrolyte (eg. water) is necessary to promote galvanic corrosion. Please see chart below.
Electric current flows from plus to minus.
Anodic (least noble) Corroded
Direction of Attack
Cathodic (most noble) Protected
Magnesium
Magnesium Alloys
Zinc
Beryllium
Aluminum 1100, 3003, 3004, 5052, 6053
Cadmium
Aluminum 2017, 2024, 2117
Mild Steel 1018, Wrought Iron
HSLA Steel, Cast Iron
Chrome Iron (active)
430 Stainless (active)
302, 303, 321, 347, 410, 416 Stainless Steel(active)
Ni-Resist
316, 317 Stainless (active)
Carpenter 20Cb-3 Stainless (active)
Aluminum Bronze (CA687)
Hastelloy C(active) Inconel 625(active) Titanium(active)
Lead/Tin Solder
Lead
Tin
Inconel 600 (active)
Nickel (active)
60% Ni 15% Cr (active)
80% Ni 20% Cr (active)
Hastelloy B (active)
Naval Brass (CA464), Yellow Brass (CA268)
Red Brass (CA230), Admiralty Brass (CA443)
Copper (CA102)
Manganese Bronze(CA675), Tin Bronze(CA903, 905)
410, 416 Stainless(passive) Phosphor Bronze(CA521, 524)
Silicon Bronze (CA651, 655)
Nickel Silver (CA 732, 735, 745, 752, 754, 757, 765, 770, 794
Cupro Nickel 90-10
Cupro Nickel 80-20
430 Stainless (passive)
Cupro Nickel 70-30
Nickel Aluminum Bronze (CA630, 632)
Monel 400, K500
Silver Solder
Nickel (passive)
60% Ni 15% Cr (passive)
Iconel 600 (passive)
80% Ni 20% Cr (passive)
Chrome Iron (passive)
302, 303, 304, 321, 347 Stainless (passive)
316, 317 Stainless (passive)
Carpenter 20Cb-3 Stainless (passive), Incoloy 825 (passive)
Silver
Titanium (passive), Hastelloy C & C276 (passive)
Graphite
Zirconium
Gold
Platinum