STUDIES ON THE MECHANISM OF FORMATION OF LITHIUM CONTAINING PASSIVE FILM ON 8090-T851 ALLOY

摘要

Weight loss and scanning electron microscopy studies were carried out to study the influence of solution pH on the formation and stability of passive film on a commercial Al-Li alloy, 8090 upon exposure to an aqueous solution containing Li~+ ions. Studies have revealed the inhibition of corrosion of Al-Li alloy by Li~+ ions. Nature of corrosion was found to be pitting, the severity of which increased with increasing solution pH for a given concentration of Li~+ ions. The solution pH was found to be critical in influencing the stability of the passive film. The passivation process has been found to be chemical in nature and the possible compound involved in the passivation process is expected to be LiA10_2.