We all take “rusting” as a necessary evil and
consider replacement of steel structures as a normal procedure. However this is not the
case at all, for there are many ways to prolong the life of such structures as tanks, dock
structures, sewage handling equipment, piping and heat exchangers just to mention a few
components of the average plant facility.
Corrosion is an electrochemical phenomena wherein a metal in the presence of an
electrolyte (water or damp soil) goes from a solid (steel) to a solute (iron ions). These
ions then oxide in the presence of oxygen within the electrolyte to form the oxide of iron
known as “rust”. The reaction of iron to iron oxide gives off electrons that
produces a minute direct current (DC). The Corrosion Engineer’s “rule of
thumb” is that one ampere of current flowing for one year will dissolve 20 pounds of
steel. So even minute current flows over a period of time will cause major metal loss.
PCA’s uniqueness is in it’s in-depth understanding of the corrosion process,
resulting in services offered in the “testing for”, “effects of”,
“remedies to” minimize or eliminate the destructive consequences.
The primary method we most often utilize to minimize corrosion is called “cathodic
protection”, either “galvanic” or “impressed”. Our objective is
similar in both approaches - reverse the current flow of the corrosive reaction, and the
corrosion process will be stopped! When small surface areas need to be protected, the
current flow of dissimilar metals coupled together is often sufficient. For instance,
magnesium metal (anode) coupled to a steel structure (cathode) results in the preferential
corrosion of magnesium, protecting the steel. For large surface area protection, a
rectifier directly imposing a DC current through an anodic material will also produce a
similar result - preferential corrosion of the anode - protection of the steel.
Knowledge and experience in the prevention of corrosion is what PCA Engineering offers.
We have a passion for service and quality, and by working with us you will soon realize
that these principals are demonstrated on a daily basis.
|
