Efficacy of Nonhexavalent Chromium Posttreatment Rinses for Passivating Three DoD Legacy Coatings: Ion Vapor Deposition Aluminum, Type III Hardcoat Anodizing, and Electroplated Zinc
Abstract
All Department of Defense maintenance facilities are under increased pressure to reduce or eliminate the use of hexavalent chromium (CrVI). CrVI has been associated with negative long-term health effects and is listed as a known human carcinogen by the International Agency for Research on Cancer. This project was designed to address the Army Environmental User Requirements and Technology Assessments requirement PP-2-02-04, for Toxic Metal Reduction in Surface Finishing of Army Weapon Systems. The goal is to identify, validate, and demonstrate the efficacy of nonhexavalent chromium posttreatment sealers on three common legacy coatings: ion vapor deposition (IVD) aluminum, Type III hardcoat aluminum anodizing, and zinc electroplating. Although the CrVI-containing passivating rinse outperformed all of the alternatives, it did not meet specification requirements in all cases. The results show some alternative passivates performed well and perhaps can be viable alternative passivates for IVD aluminum and Type III hardcoat anodizing. No alternative sealer performed nearly as well as CrVI passivates on electroplated zinc coatings. More work is needed to develop an effective nonchromium passivating rinse for electroplated zinc coatings.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 21, 2021
- Accession Number
- AD1137674
Entities
People
- John Kelley
- Thomas Braswell
- Thomas Considine
Organizations
- United States Army Research Laboratory