Galvanic Corrosion

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