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Over the past 60 years, chemical companies have been supplying automotive manufacturers state-of-the-art zinc phosphate conversion coatings which, when applied properly to a metal surface promote excellent paint adhesion and corrosion resistance. Phosphate conversion coatings have undergone many transformations over the years. Now some of their essential components and byproducts are being more tightly regulated under new environmental guidelines. The metal pretreatment industry is now challenged with the task to replace the traditional zinc phosphate coating with the next generation product. This paper will examine the advantages of a new generation conversion coating based on zirconium oxide. The performance and process cost savings will be discussed. This technology has been advancing over the past several years, and in 2007 several successful commercial line trials with this new conversion coating were conducted.

Autodeposition coatings are thin, highly corrosion resistant organic coatings that deposit paint by reaction with the metal surface. The coating deposits only on metallic surfaces, thus allowing coating of just the metal portion of metal-plastic or metal-rubber assemblies. Because it is a chemical reaction with the metal surface, it is possible to evenly paint the inside of tubular and boxed sections, which is where corrosion typically starts. The overall autodeposition process includes cleaning, water rinse, coat, reaction rinse, and cure. The use of a reaction rinse after the autodeposition coating application allows unique properties to be introduced to the coating before curing. This presentation will briefly review the general chemistry of autodeposition. Next it will focus on commercial automotive applications of several newly developed autodeposition coatings. The corrosion performance and physical characteristics of both black and gray epoxy-acrylic coatings will be presented.

Autodeposition coatings are thin, highly corrosion resistant organic coatings that are deposited in a chemical reaction with a metal surface. Because the autodeposition process deposits a coating only on metallic surfaces, coating of just the metal portion of metal-plastic or metal-rubber assemblies is possible. The overall autodeposition process includes stages of clean, water rinse, coat, reaction rinse, and cure. The use of a reaction rinse after the autodeposition stage is unique among coating processes and allows new properties to be introduced to the coating before curing. This paper will briefly review the general chemistry of autodeposition, and then focus on how corrosion performance and physical characteristics of a recently developed epoxy-acrylic autodeposition coating are designed into the product and how the autodeposition process controls these properties. The role of the organic polymer and the reaction rinse in all the properties will be discussed.