ELECTROCHEMICAL NOISE MEASUREMENTS AT A PLANT FOR CONDITIONING OF INDUSTRIAL-WASTE WATER

Damage by pitting corrosion occured at parts of a plant (duplex steel, material no. 1.4462) for conditioning of process and waste waters aft er some weeks. By examination of the electrochemical noise it should b e analyzed, under which conditions increased corrosion propensity (pit initiation) appears and whether another material (Alloy C 4, material no. 2.4610) has a higher corrosion resistance under the given conditi ons. As example for practical use of electrochemical noise diagnostic under operating conditions it is shown, how several short time tests u nder different medium conditions allow to draw conclusions with respec t to to the corrosion propensity of the materials examined. The compar ison with results from accompanying laboratory examinations have shown good agreement. The great influence of ammonium concentration on the corrosion behaviour of the duplex steel was recognized in all investig ations examined.