Chemical treatment of aluminum is a common industrial practice. In fact, nearly all aluminum used in manufactured products is painted.
Paint will not bond to aluminum castings or plate aluminum without a proper surface treatment. Chemical treatment of aluminum needs to be approached differently than steel. One does not use caustic based cleaners when cleaning aluminum. Caustic based cleaners are too aggressive on the surface. In addition, the types of mill lubricants, cutting oils, and stamping compounds used on aluminum are different to that found on steel. This is one reason chemical treatment of aluminum is treated differently.
There are two methods when applying metal finishing chemicals to metals. One uses either a manual or an automatic application. Manual applications are typically done when we encounter large awkward parts such as airplanes, boats, locomotives, tanker trucks, mining equipment, and other parts that cannot be readily run through a spray washer or immersion system. Smaller parts such as widgets to automobiles are normally run through automatic washer systems.
Chemical treatment of aluminum will depend on its end use. For items that are exposed to outdoor elements, like cars, boats, and planes, a very high quality pretreatment and painting process is necessary. For other parts not exposed to the elements, a more simplistic chemical treatment of aluminum and paint process is suitable.
Farayand Yekta Pajooh has products for all these different types of chemical treatment of aluminum. For a description of these processes and the Farayand Yekta Pajooh products necessary for those different applications, see Phosphoric Acid on Aluminum technical article.