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Surface pretreatments based on dilute hexafluorozirconic acid (FZ) solution were evaluated as replacements for the phosphating process before paint application. The behavior of a FZ coating was compared to those of a modified FZ (MFZ) coating and phosphating treatments. Results of electrochemical tests on painted cold rolled steel (CRS) samples with different conversion coatings show that the MFZ surface treatment in combination with various paints provides corrosion protection performance comparable to phosphate conversion coatings. AFM studies of MFZ coatings on CRS reveal that the coating surface exhibits small features tens of nm in size and clusters of these features that are on the scale of microns. Clusters have lower surface potentials (higher activity). Z-contrast TEM images of MFZ coatings show that the coating is about 20 nm thick, continuous and adherent to the substrate. Major components are Zr, Fe and O; the Fe amount decreases toward the coating surface.

Modifications to the Limiting Dome Height test method and instrument enable in-lab production of controlled metal panels that can be used for cleaning and coating testing after stamping lubricant performance testing is complete. The differences in results between stamped and unstamped (flat) panels on a variety of common stamping lubricant acceptance tests will be explored using existing approved stamping lubricants. The value of using a standard stamped part for lubricant, cleaner, and coating development will be described. The importance of real-world process simulation will be reviewed in the context of coating failures.

Autodeposition is an immersion, direct-to-metal coating process that forms a paint film on metal surfaces by a chemical reaction between an aqueous paint dispersion and the base metal. The autodeposition process consists of cleaning, rinsing, organic coating deposition, and a sealing rinse. Conventional pretreatment/primer systems require full thermal cure prior to topcoat application because of volatiles that must be lost during cure. The latest autodeposition chemistry consists of an epoxy-acrylic hybrid mini-emulsion. The chemical combination of a flexible, high molecular weight acrylic with a hard, tough epoxy in a semi-interpenetrating network provides a very low VOC (≤0.03 lb/gal) coating. Upon dehydration ~100°C, the autodeposited coating provides a dry-to-handle, tack-free film with physical integrity. A powder topcoat or sealer/adhesive can be applied to the dehydrated autodeposited coating.

In recent years, automotive component manufacturer's use of autodeposited coatings has dramatically increased due to the performance, cost-effectiveness, versatility and environmental advantages that this technology offers. Although historically used to coat only steel substrates, the increased use of zinc and zinc alloy coatings presents further market opportunity for autodeposition of coatings. Due to differences in chemical reactivity between steel and zinc, obtaining high quality coatings by acidic chemical deposition (autodeposition) has required some process development innovations. In this paper, the procedure of coating deposition on galvanized surfaces is described and compared to the deposition on steel. Corrosion performance of autodeposited coatings on galvanized steel is evaluated by a cyclic corrosion test and compared to the performance of another widely used coating for galvanized substrates.