Zur Korrosion von Aluminium-Werkstoffen in Salpetersäure

Corrosion of aluminium and aluminium alloys in nitric acid A literature survey was made to show the suitability of aluminium and aluminium alloys in contact with highly concentrated nitric acid, particularly with regard to the corrosion behaviour of weld joints made using various welding processes. The corrosion resistance of Al99.5 in nitric acid was investigated as functions of temperature and acid concentrations. The linear corrosion rates are plotted in an Arrhenius diagram. Decreasing nitric acid concentrations are causing a parallel shift of the lines in the Arrhenius diagram towards higher corrosion rates. Starting with A199.5, the corrosion rates in nitric acid at and above 99.8 concentration decrease as the A1 contents of the materials increase. Doping with copper should be avoided. After exposure of wrought as well as continuously cast A1 and A1 alloys to highly concentrated technical grade nitric acid at 30 °C (1 year test period), the corrosion behaviour of a number of alloys was comparable to that of pure aluminium grades.