Potentials of selected metal alloys in sea water at elevated temperatures

Sixteen metal alloys were studied in aerated sea water at temperatures up to 2000C, and five of these were further studied in deaerated sea water in the same temperature range. Galvanic series are reported for temperatures of 30, 100, 160, and 2000C in an autoclave, and for a trough at ambient conditions. The general effect of increased temperature in both aerated and deaerated sea water was to increase the electronegativity of most metals, and to reduce the spread between the median potential values. At 2000C, the metals merged into two groupings: aluminum and zinc being the most active, other metals were appreciably less negative. In contrast to other metals, zinc and carbon steel showed a tendency toward nobility at higher temperatures. Very small differences were found between the galvanic potentials of most metals in deaerated sea water as compared with these metals in aerated sea water. Titanium appeared to be the exception, being more active in deaerated sea water above 1200C