ON THE CORROSION CHARACTERISTICS OF SOME MODIFIED ALUMINIUM ALLOYS IN SEAWATER WITH DIFFERENT PRETREATMENTS UNDER DYNAMIC AND NEARLY STATIC CONDITIONS.

Al-Mg, Al-Cr, Al-Mg-Cr and Al in annealed and cold rolled forms have been prepared and their corrosion characteristics at 313K in seawater under dynamic and nearly static conditions with differing water chemistry have been studied. Electrochemical observations made after different pretreatment under stirred conditions have enabled understanding of the mechanism of corrosion. Jet impingement and crevice corrosion studies were also carried out. Uniform velocity and impingement velocity corrosion rates have shown that generally Al-Mg-Cr and Al-Cr behaved better than the other alloys. The dynamic corrosion rates for Al-Mg-Cr and Al-Cr alloys in deaerated seawater suggest their superior performance at higher temperatures.