Assessment of Oyster Shell Structural Properties for the Development of \u27Green\u27 Composite Materials

Abstract of Technical Paper Presented at the 101st Annual Meeting National Shellfisheries Association Savannah, Georgia March 22–26, 200

Electrochemical Evaluation of the Compatibility of Fresh and Aged NovecTM 71IPA with Beryllium, Stainless Uranium, 304L Stainless Steel, and 2024-T3 Aluminum Alloy

This study was a material compatibility assessment of four metals (beryllium, stainless uranium, 304L stainless steel, and 2024-T3 aluminum) with an environmentally benign, non-aqueous, near-azeotropic mixture of hydrofluoroether (Novec™ 7100) with 4.5 wt% isopropanol designated Novec™ 71IPA. The intent is to use the Novec™ 71IPA to clean materials in sensitive, long-term assemblies. There is concern when an aged solvent is used to clean a metal surface, it may cause corrosion due to fluoride formation as the solvent ages. Two solvent conditions, one having no detectable fluoride (fresh) and the other with ≥17 ppm fluoride (aged) were evaluated. Electrochemical evaluations using impedance spectroscopy were performed to monitor the metal surfaces for signs of reaction. Microscopic and spectroscopic techniques, including X-ray photoelectron spectroscopy, were used to characterize the metal surfaces before and after electrochemical tests. Increased impedance was observed when beryllium substrates were exposed to fresh or aged Novec™ 71IPA and was attributed to formation of organic and/or inorganic films on native beryllium oxide. Other metals exhibited insignificant changes in impedance but did show some passive film formation. Results confirmed Novec™ 71IPA, containing up to 17 ppm fluoride, had no corrosive effect on the four tested metals and may be used to safely clean them