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- Korrosionsprüfung (2)
- CMT (1)
- Cold metal transfer (1)
- Elektrochemie (1)
- Elektrochemisches Rauschen (1)
- Korrosionsschutz (1)
- Nickelbasislegierung (1)
- Nickellegierung (1)
- Plattieren (1)
- Plattierung (1)
Claddings of different nickel based alloys were generated on a mild Steel (S235JR) and a stainless steel type 304 by Cold Metal Transfer (CMT). This welding procedure possesses a low degree of mixing between the Substrate and cladding material. Thus it improves the corrosion behaviour of the claddings. The aim of our investigations was to examine the effect of the welding parameters: energy per unit length, shielding gas and finishing surface treatment on the pitting corrosion behaviour of the claddings.
However, under Standard test conditions nickel based alloys are often resistant to pitting corrosion. Moreover these test methods are inaccurate and require a large period of time resulting from the iterative progress to determine the critical pitting temperature (CPT). A potentiostatic test method was modified using a high concentrated CaCI2-solution and a conventional three electrode measuring cell. The pitting corrosion behaviour is calculated from current noise charges. During the test the course of corrosion is detected online by the evaluation of electrochemical noise Signals while a continuous increase of temperature by a defined heating rate is realised.
Thus a critical pitting temperature can be estimated by only one attempt. Furthermore the deviation of the measured CPT is very low compared to Standard tests using gravimetrical and microscopic evaluation. That enables to figure out the influence of the welding parameters in an exact way.