Non-Chrome Posttreatment for Zinc ASTM B633

Author(s):

Lindsey Blohm, Thomas Braswell, and John Kelley

Abstract:

There are currently no qualified non-chrome posttreatments for zinc (Zn) plating for US Army applications, necessitating the investigation of novel non-chrome systems for passivation of Zn plating and commercially available alternatives to validate and demonstrate on Zn plating for ground vehicle and aviation platforms. Following a memo from the Assistant Secretary of the Army, it is a high priority to find a qualified chrome alternative. Chromic acid, a known human carcinogen, is targeted for replacement as it is undergoing increased regulatory restrictions. Building on previous work performed by the US Army Combat Capabilities Development Command (DEVCOM) Army Research Laboratory (ARL) and US Army Aviation and Missile Command G-4, ARL will perform a battery of testing on industrial sealers and two novel technologies, comparing them with hexavalent chromium and trivalent chromium control systems. Performance objectives with acceptance criteria have been developed. Testing includes adhesion, corrosion resistance, and electrochemical behavior.