Corrosion handbook

16 06/21
Humidity test: EN ISO 6270/ ASTM D2247, and with sulfur dioxide (EN ISO
6988, ASTM G87)
In the humidity test, samples are exposed to an atmosphere with 100 % relative
humidity. This test can be combined with the addition of a certain amount of
sulfur dioxide gas. This creates a highly corrosive and acidic environment that
simulates the effect of heavy industrial pollution (see Fig. 20).
Electrochemistry
The electrochemical nature of the corrosion process make electrochemical
techniques useful for the investigation of corrosion reactions of certain materials.
Besides the accelerated corrosion tests, our lab is equipped with electrochemical
testing equipment (potentiostat) which is mainly used for the examination of
pitting corrosion and the repassivation behavior of stainless steel.
Metallographic laboratory
Accelerated corrosion tests, as well as field exposure tests always have to be
supported by various analytical methods for proper interpretation of the results.
In the metallo graphy lab we use a state-of-the-art scanning electron microscope
(SEM) plus elemental analysis for deeper investigation of our products (see Fig.
21, Fig. 22 and Fig. 23).
steel
orignal coating
corrosion products
Fig. 22: Metallographic cross section in the scanning electron microscope of a
ZM coating after three years exposure in a coastal climate. The stable corrosion
products help protect the layer from further attack.
Fig. 20: Screws with highly corrosion-
resistant multilayer coating after 15
cycles of the sulfur dioxide corrosion
test (showing no corrosion).
Fig. 21: Scanning electron microscope
(SEM).
Fig. 23: Metallographic laboratory
equipment (grinding and polishing).