Environmentally Friendly Fastener Coating Demonstration

WP-201315

Objective

Traditionally, steel fasteners have been used with cadmium electroplated coatings followed by a hexavalent chrome rinse. The environmental hazards associated with cadmium and hexavalent chromium are well established and significant legislation has been put in place recently to limit their continued usage. It is critical that suitable replacement technologies be identified that can provide these high performance characteristics in a cost effective manner. The objective of this project is to demonstrate for the Department of Defense (DoD) high performance coating technologies which eliminate the need for cadmium or hexavalent chromate coatings on high-strength fasteners. This will provide high-strength, corrosion resistant fasteners for use on legacy weapon systems and new weapon platforms.

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Technology Description

Two separate fastener coatings systems have been selected for the demonstration and validation program. Both coating systems include a sacrificial metal base coat (zinc or aluminum), and an organic electrocoat topcoat technology that eliminates environmental concerns associated with currently fielded cadmium and chromium replacement coating systems. The zinc/electrocoat coating system consists of an inorganic metal flake dip-spin coating based on unique inorganic binder and zinc flake technologies. This, in combination with the topcoat, will offer a high end corrosion option which is commercially available at equal or lower cost versus cadmium or other plating alternatives. In contrast, the aluminum/electrocoat coating system consists of high purity aluminum plating, (HPAP), coupled with the electrocoat topcoat. This combination provides the highest level of corrosion performance, closest to that of cadmium, but at potentially higher cost versus cadmium. Each of the basecoat technologies provide the corrosion resistance and performance characteristics required of a number of high strength fastener designs. The organic electrocoat topcoat layer provides the additional barrier properties, corrosion resistance and the required torque tension characteristics.

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Benefits

Elimination of hazardous materials currently used for high-strength fasteners will substantially improve the life cycle costs as well as environmental and occupational health issues associated with the manufacture and maintenance of DoD weapon systems. During parts processing, cadmium presents both personnel, and environmental hazards. The approach would impart high end sacrificial corrosion resistance properties without the use of hazardous chrome or cadmium and without embrittlement of fasteners. (Anticipated Project Completion - 2016)

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Points of Contact

Principal Investigator

Mr. Matt Scott

PPG Industries Inc.

Phone: 412-492-5594

Fax: 412-492-5522

Program Manager

Weapons Systems and Platforms

SERDP and ESTCP

Document Types

  • Fact Sheet - Brief project summary with links to related documents and points of contact.
  • Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
  • Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
  • Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
  • Guidance - Instructional information on technical topics such as protocols and user’s guides.
  • Workshop Report - Summary of workshop discussion and findings.
  • Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
  • Model/Software - Computer programs and applications available for download.
  • Database - Digitally organized collection of data available to search and access.