The Replacement of Chromium Electroplate for High Wear/High Temperature Applications

ABSTRACT: This proposal translates a non-toxic, aqueous-based, near room temperature electrodeposition process to completely eliminate Cr (VI) for the production of wear and corrosion resistant surfaces on high-strength steel. Specifically, our process will produce adherent and crack-free Re-based coatings that are extremely high-temperature (Tm of Re = 3180oC), lubricious, wear-resistant, and corrosion-resistant. Examples of components that could benefit include: landing gear pistons, rail-gun rails, high caliber gun barrel linings, rocket nozzles, among other strategic components. We will examine the role of various strike layers and alloying using Fe, Sn, Zn, and In as they affect Faradaic efficiency, reduction in Re content, coating adhesion, room temperature wear properties, and corrosion properties. ASTM methods will be used in all cases. The morphology and elemental content will be determined using SEM and EDS. The corrosion behavior will augmented using open circuit potential measurements and EIS measurements over time. Electrodeposition utilizes this strategically important material with 100% efficiency, the ability to produce coating thicknesses of any dimension, and the ability to coat any complex structure and re-entrant angles. All bath components are non-toxic materials that are not on the watch list.; BENEFIT: This project will develop a non-toxic, aqueous based, electrodeposition process to produce an adherent, crack-free Re-based coatings on high-strength steel. These coatings have strategic advantages for the DoD in their high temperature, low coefficient of friction, low wear, and high corrosion resistance properties. The ability to eliminate Cr (VI) completely added to these performance properties make this a compelling process to increase worker and mission safety, reduce handling and monitoring costs for Cr (VI), and provide strategic operational advantages to the aircraft or weapon system. There are also potential civilian applications of this methodology where high temperature performance, high wear and corrosion resistance, and lubricious characteristics are needed such as aircraft engine components in marine environments.