The presence of hydration products on aluminium surfaces can modify the aluminium surface properties concerning subsequent storage, adhesion or weldability. The first aim of the work presented in this paper has been to beable to detect the hydration of a surface using a combination of both vis-SE &and IRSE, which are relatively quick and non-destructive methods. Using this ability, the second aim has been to compare differently treated panels of pure aluminium (rolled AA1050 and a rolled AA 5xxx), which have undergone identical hydration tests, i.e., immersion in boiling water. Scanning Electron Microscopy (SEM) is used to have a visual idea of the topography of the hydrated surface. The pre-treatments consist of different types of commercial etchants, i.e., alkaline, acidic or a combination. The role of ZrTi passivation as a hydration inhibitor is also included in the study. The paper concludes that the amount of hydration remains relatively independent in respect to the type of etching. The chemical composition of the hydration layer also remains unchanged. Prior etching influences the ZrTi passivation layer formation and this passivation treatment leads to the inhibition of any further hydration of the substrates.
Discussion(0)
No comments yet. Be the first to comment.