Molybdenum uses
If your project looked good when it was installed last year but staining began to appear over the Winter or Spring, the problem may be exposure to deicing salts. Salts from deicing are not just a problem at ground level – they have been detected as high as the 59th floor on city buildings and over 1 mile (1.6 km) away from busy roads.
The use of deicing products is increasing around the world and the chemicals used are changing, which is making the environment more corrosive for all construction materials.
Many road maintenance authorities are now using calcium or magnesium chloride, applied as a liquid. These chloride salts are more corrosive then traditional rock salt (sodium chloride). Corrosive fertilizer by-products are also being used for deicing, with some marketed as “environmentally friendly”.
The addition of molybdenum to stainless steel increases its resistance to corrosion caused by deicing salts, coastal atmosphere and pollution. You can read more about the risk of corrosion and the specification and care of appropriate grades of stainless steels below:
Suggested reading:
This Type 316 bollard in Düsseldorf, Germany, illustrates the importance of surface finish. The much smoother finish on the top retains less salt and has much less corrosion then the rougher bottom finish.
Photo C. Houska, TMR Consulting
