Corrosion Coupons

What are corrosion coupons ? 

Corrosion coupons are a widely used and relatively simple form of corrosion monitoring. Usually a coupon is exposed to a corrosive environment to represent an actual component/structure. Subsequent to their exposure, coupons can be weighed and examined microscopically to assess the mode and average rate of corrosion damage. This form of corrosion monitoring is therefore usually of a retrospective nature - only a snapshot of the cumulative corrosion damage at the end of the exposure period is provided and little information is available on specific events that may have triggered this damage.

Why corrosion monitoring is important ? 

Accurate monitoring of corrosion rates in any environment is critical when viewed in terms of the maintenance and repair costs associated with corrosion and material failure. Test coupons provide an inexpensive means of on-line monitoring that will allow you to effectively measure the corrosivity within your system. By observing the mils-per-year corrosion rate of an exposed coupon, valuable information can be provided regarding the material's life expectancy.

Why corrosion testing is important ?

Corrosion tests are conducted for a number of reasons, some of which are:
To provide an insight into corrosion mechanisms.To compare resistance of one alloy to another under standard conditions (in alloy development work for example).As a quality control test for a given heat of alloy.To provide a basis for estimating service life of process equipment.