Site hosted by Angelfire.com: Build your free website today!

 

GALVANIC CORROSION


 

TABLE A - FACTORS AFFECTING THE RATE OF GALVANIC CORROSION

Characteristics of Electrolyte

Water, moist air, mineral acids and mineral salts are common electrolytes in galvanic corrosion. Corrosion is more rapid where strong mineral acids or salts are present.

Potential Difference

The more reactive metal has a higher potential in corrosion. The more remote two metals are in scale, the greater is the reaction/corrosion. Details are in Table B.

Relative Area of Metals

When the area of the anode is small compared with that of the cathode, galvanic corrosion is more serious.

Temperature

The rate of galvanic corrosion increases with temperature. At a certain temperature, the galvanic corrosion can even reverse in direction (i.e. cathodic metal is corroded). A common example is galvanic corrosion between zinc and steel at about 70° C.

 

TABLE B - TYPICAL GALVANIC SERIES OF METALS AND ALLOYS


Reactivity in ascending order

Platinum

Gold

Graphite

Silver

Hastelloy C

18-8-Mo Stainless steel

18-8 Stainless steel

Chromium irons

Inconel

Nickel

Silver solder

Monel

Copper-nickel alloys

Bronze

Copper

Brass

Stainless Steel

Tin

Lead

Lead-tin solders

Chromium

Nickel cast irons

Cast irons

Carbon steel

Aluminium alloys (2017, 2024)

Cadmium

Aluminium alloy 1100

Zinc

Magnesium alloys

Magnesium


# Metals in bold and italic are mentioned in this thesis.

 

Previous Page

Next Page