The thermodynamic conditions of chemical stability for the three-metal, Aluminium—Copper—Steel/ closed water systems are outlined, together with an account of the corrosion behaviour of aluminium as affected by the pH of the water and the presence of inhibitors. A practical case is described of incorrect chemical treatment of the recirculating water in an air-conditioning multimetal system, leading to overall instability of the protective aluminium oxide layer with typical forms of aluminium attack arising from a combination of high alkalinity (here due to borate) with too low a concentration of inhibitor, and water turbulence.
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References
1.
PourbaixM., ‘Atlas of Electrochemical Equilibria in Aqueous Solutions’.1966 (New York: Pergamon Press)
2.
BrownB. F., CEBELCOR Bulletin E. 76, 8, 1. 1969
3.
WranglénG. ‘An Introduction to Corrosion and Protection of Metals’. 1972, p. 70 (Frome & London: Butler & Tunner Ltd)
4.
BingerW. W., in ‘Corrosion Resistance of Metals and Alloys’. Ed.LaQueF. & CopsonH. R.. 1963, p. 183 (New York: Reinhold Publ. Corp.)
5.
Dra1ey & Ruher in ‘Corrosion and Corrosion Control’. Ed. UhligH. H.. 1971, p. 299 (New York: Wiley & Sons)
6.
TomashovN. D., ‘Theory of Corrosion and Protection of Metals’.1966, p. 613 (New York: Macmillan)
7.
Crossfield & Sons Ltd, Anti-Corrosion. June1971, p. 16
