Corrosion of Metals and Alloys
To understand the electrochemical nature of aqueous corrosion
To explore electrochemical methods of corrosion control
Corrosion is a complex phenomenon that incorporates elements of materials science,
chemical engineering, chemistry, physics and quantum mechanics. This introduction is a
brief qualitative exposure to some fundamental aspects of corrosion. Experiments are
conducted to illustrate the galvanic series, electrode polarization, the oxygen concentration
cell, galvanic current, and galvanic protection.
weight percent sodium chloride solution (35 grams per liter of water)
Strips of copper, brass, zinc, iron, mild steel, aluminum, nickel, and other metals.
Calomel™ reference electrode
600ml beakers and electrode holders
A ruler for measuring electrode areas
Steel wool and sandpaper to clean the electrodes
Clip leads to connect the various electrodes
Corrosion Lab and Corrosion Lab Stripchart virtual instruments
Mild steel sheet
Phenolphthalein-ferricyanide indicator (20 grams sodium chloride, 2 grams potassium
ferricyanide, and 2 ml phenolphthalein solution in 1 liter of water).
Corrosion is an
process by which metallic species are caused to oxidize.
The type of corrosion explored in this lab is
(water) based corrosion, however
corrosion can take place in solid electrolytes such as lithium polymer batteries, or in thin
surface films, as in fuel cells.
The most visible form of corrosion is the formation of oxides and hydroxides of iron, which
we generically call “rust.” When we immerse mild steel into water, we observe the
formation of rust. What we do not easily see is the reduction of oxygen that accompanies
this process. If it were not for the reduction reaction, corrosion could not take place. Since
corrosion is an
process, the release of electrons must be compensated by
the consumption of electrons elsewhere (or else charge neutrality would be violated).