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Effects of graphite-epoxy composite materials on the corrosion behavior of aircraft alloys. Phase report

Technical Report ·
OSTI ID:7346640
The electrochemical approach was used to show the nature of the galvanic corrosion when graphite-epoxy composite materials are coupled to aluminum and titanium alloys. An open circuit potential difference of one volt was obtained in 3.5% NaCl solution between the composite and 7075-T6, 7075-T651 and 5052-H38 alloys. This potential difference provides a driving force for corrosion and is cause for concern. The Ti-6-4 showed a difference of about 0.3 volt for the unpolished as received material. Corrosion current data (zero impedance technique) indicate that aluminum alloys and cadmium plate are much more reactive than Ti-6-4 when coupled to graphite-epoxy. This technique provides a means of ranking the severity of this corrosion problem for various aircraft alloys. Flatwise tensile data indicate significant strength losses when graphite-epoxy composite sandwich specimens are exposed to ASTM 5% salt spray and synthetic sea water + SO/sub 2/ spray environments.
Research Organization:
Naval Air Development Center, Warminster, Pa. (USA). Air Vehicle Technology Dept.
OSTI ID:
7346640
Report Number(s):
AD-A-010127; NADC-75031-30
Country of Publication:
United States
Language:
English