Analysis of the methods available for the removal of sodium from corrosion test samples

The reactions of several corrosion products with water, acetic acid and ethanol have been investigated. The removal of sodium from the corrosion products was shown to be rapid in many cases, and all the corrosion products studied were most affected by water, and to a lesser extent by acetic acid and ethanol. Reaction temperatures for the interaction of sodium oxide with metals and alloys have been determined by thermal analysis methods. These temperatures may be used to determine the maximum distillation temperature for the removal of sodium from a test sample so that interaction with precipitated sodium oxide does not take place. A method is described for the dissolution of NaCrO2, Fe and Ni from the surface of stainless steel. This method may be used to compare the amounts of corrosion product remaining on the surface after the excess sodium has been removed by vacuum distillation or washing with water, acetic acid and propanol. In all cases examined, vacuum distillation gave the most corrosion product on the surface