Aluminum Alloy metal have many kinds of composition and it mean has been difficult to find a certain preplating procedure that will be equally satisfactory for all types and tempers of aluminum alloys, since the various alloys and products exhibit different metallurgical structures and different electrochemical behavior. Every alloy elements have different characteristic and structure that can effect to the behavior when treat with electroplating on aluminum metal.
When alloying elements are added, they may appear in an aluminum alloy in several different forms - in solid solution in the aluminum lattice, as micro-particles of the elements themselves, or as particles of intermetallic compounds formed by combination with the aluminum or other alloying elements. Metallurgical structure of aluminum will change after mix with some other metal, and this make the alloy possible be plated. Different with the original aluminum or pure aluminum is bad if being plated. Because the aluminum itself will react with the chemicals solution in the bath.
The several solid solution matrices and the 20 or more microconstituents that may occur in commercial alloys may have different chemical and electrochemical reactivities, and their surfaces may not respond uniformly to the various treatments.
Basic pretreatment to obtain consistent result with any process for plating on aluminum and especially for those involving an immersion treatment, it is essentially that the various cleaning and conditioning treatments provide a surface of uniform activity. Basically of this treatments are remove of metal surface from oil, grease, or other foreign material.
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