Rapid Electrochemical Characterisation of Corrosion Properties of Aluminium Brazing Sheet by Stepwise Dissolution Measurement

For aluminium heat-exchangers one of the most accepted corrosion tests is the SWAAT. It is widely used by both aluminium producers and manufacturers of heat-exchangers. However, in alloy development programmes, as well as in production environments even faster characterisation of corrosion properties of aluminium brazing sheet would be advantageous.

The Stepwise Dissolution Measurement (SDM), which is an electrochemical technique, was developed in our laboratory to enable rapid screening of corrosion properties of aluminium brazing sheet. Within approximately 6 hours it is possible to distinguish between Long Life (over 25 days SWAAT performance) and non Long Life materials. Cross section showed that the mode of attack in SDM is similar to the mode of attack in SWAAT exposure.