Environmentally Friendly Anticorrosion Coating for High Strength Fasteners
Final rept. 1 Oct 2008-30 Sep 2010
PPG INDUSTRIES INC ALLISON PARK PA PPG COATINGS AND RESINS GROUP
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There exists a need for environmentally benign coatings to eliminate cadmium andor chromate containing coatings on high-strength fasteners. These alternative replacement coatings would provide high-strength, corrosion resistant fasteners for use in weapon systems. Traditionally, high-strength steels have been used with cadmium Cd electroplated coatings, followed by a hexavalent chromium Cr6 rinse. The environmental and human health hazards associated with both cadmium and chromates are well established. The elimination of hazardous materials will improve the life cycle costs and environmental occupational health issues associated with the manufacture and maintenance of DoD weapon systems. Alternatives to both processes have been pursued with very promising results. This work describes a multi-layer approach to provide a protective coating system. These systems include a sacrificial metal base coat and may also include an organic topcoat technology that will provide the best combination of corrosion resistance and barrier properties. These approaches impart high end sacrificial corrosion resistance properties without use of hazardous Cr or Cd and without hydrogen embrittlement of fasteners.
- Coatings, Colorants and Finishes
- Properties of Metals and Alloys
- Couplers, Fasteners and Joints