AN ELECTROCHEMICAL SODIUM SENSOR FOR ALUMINUM MELTS

The modification of aluminium-silicon alloys by sodium addition before casting results in an improvement of the mechanical properties of the alloy. As sodium has a high reactivity with air, it forms sodium oxid e or sodium hydroxide vapours and the total amount of sodium in the al loy decreases as a function of time. This paper describes the developm ent of test results of an electrochemical sodium sensor for the determ ination of sodium in an aluminium-silicon alloy. The described experim ents show the promising features of such a sensor in the aluminium cas ting industry, where the sodium level must be held between 50 and 200 ppm for modification of the alloy.