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| U.S spends $276 billion in year in costs related to corrosion |
On a warm day in June,
an old fisherman went out to the docks to begin the days work. As he boarded, he noticed a small puddle of
water near the back of the boat. He got out, started pulling up the floor and
realized the aluminum, underneath, had begun to corrode. The boat would have to
be fixed, which would cost him time and money. We may not all deal with the
affects of corrosion in our daily lives, but the costs of corrosion are
extremely high and can be cut drastically by proper corrosion prevention
methods. Battelle, a nonprofit research and development organization, estimates
that as much as $100 billion could be saved. In an experiment, one method of
corrosion prevention was investigated. The purpose was to investigate the idea
that corrosion of iron is an electrochemical process, that electrons travel
from point of oxidation to point of reduction and then test the ability of
zinc, copper and magnesium to protect an iron nail from corrosion.
Background
Simply put, corrosion is
a chemical, oxidation reduction, reaction in which a solid is eaten away.
Specifically, the iron metal is oxidized and the oxygen is reduced. These
oxidation reduction reactions are also referred to as anodic and cathodic
reactions and take place on different areas of the metal's surface. Where the
oxidation takes place is considered the anodic area and where the reduction
takes place is considered the cathodic area. The anodic and cathodic areas can
each be determined respectively by attaching multimeter leads to the metals.
The black lead will give you a positive reading and will be attached to the
metal that is an anode, which means oxidation is occurring. The read lead will
be attached to the metal that is the cathode, which means reduction is
occurring. The process will be visualized by ferricyanide, which will turn blue
during oxidation, and phenolphthalein, which will turn pink during reduction.
In order to prevent corrosion, an active metal will literally sacrifice itself
giving the name, sacrificial anode. Zinc, copper, and magnesium were
tested to see if any protected an iron nail from corrosion.
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| A depiction of the experiment |
The Experiment
To determine the ability
of zinc, copper, and magnesium, agar was poured into four separate Petri
dishes. One dish contained just an iron nail, one contained an iron nail and
copper, an iron nail and zinc, and an iron nail and magnesium. The metals and
iron nails were half in the agar and half out. The halves that were out of the
agar were connected to multimeter leads and an electrical current ran through. For just the
iron nail, a pink color formed around the tip and blue around the head. For the
iron nail and copper, blue formed around the iron nail and no color formed
around copper. Next, zinc had turned pink and the iron nail turned blue as
well. Last, the magnesium turned pink and the iron nail turned blue. The
results of the experiment were that copper would act as a sacrificial anode,
but zinc and magnesium turned pink showing reduction occurred.
Material Sciences
Battelle is working to
develop many different anti-corrosive materials, corrosion resistant coatings,
and other improvements to cut the costs of corrosion. Please feel free to share if you know of any other corrosion prevention experiments, the results of your own experiments, or even your results of this experiment.
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| A sacrificial anode being used at sea |
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| A sacrificial anode being used underground |
