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2065801 
Technical Report 
Replacement of Chromates in Paints and Corrosion Protection Systems (Second Stage Results) 
Rivero-Hudec, MA; Brown, R; Yang, SC 
2004 
NTIS/02930484 
GRA and I 
GRA and I 
This technical report presents the second stage results of a multi-year project to develop chromate-free paints and corrosion protection systems. Chromate-containing coatings and paints are very effective in providing corrosion resistance and are widely used in the manufacturing, transportation and defense industries; however, there is a need to find an environmentally- and occupationally-friendly replacement to chromate (chromium VI is considered a carcinogen with an extremely low personal exposure limit). The tasks of this stage consisted of the corrosion testing of an alternate-to- chromate coating applied to 10x3-in aluminum alloy samples, assessment of biocorrosion on aluminum alloy samples, and development and corrosion testing of a wash primer and electrophoretic coatings. The alternate to chromate coating involves substituting titanium for chromium (titanium is much safer than chromium and it is used for hip replacement in humans). The new formulation protects in the same manner as chromate and has been able to match the test data for chromated surfaces. It was found that: the conversion-coating time affects the quality and performance of the coating; wash formulations for the pretreatment of aluminum surfaces influence the adhesion of the electrophoretic coatings; and that exposure of aluminum alloy samples to suspensions of marine bacteria exhibit an increase in the corrosion rate. The report ends with a summary of future tasks to further develop chromate-free paints and anti-corrosion systems.