AN HYDROGEN EVOLUTION METHOD FOR THE ESTIMATION OF THE CORROSION RATE OF MAGNESIUM ALLOYS

摘要

Due to the negative difference effect, a special electrochemical phenomenon for magnesium and its alloys, significant errors can be introduced into corrosion rate measurements when using traditional electrochemical techniques. Also, the classical weight-loss method only provides final corrosion information (or an integrated corrosion rate), and moreover errors may easily be introduced into the final result during the removal of corrosion products and in the calculation of the corrosion rate. This paper experimentally and theoretically demonstrates the use of a hydrogen evolution method for measuring the corrosion rate of magnesium and its alloys. The following are shown. 1) The amount of hydrogen collected is equal to the amount of magnesium dissolved. 2) The collection of evolved hydrogen can reveal the instantaneous corrosion rate, and the changing corrosion behaviour of magnesium and its alloys. 3) Smaller theoretical and experimental errors are introduced by the hydrogen evolution collection method. Most importantly, this method is easy to set up and operate, and is suitable for a quick evaluation of corrosion performance and monitoring of the corrosion behaviour of magnesium and its alloys.