The effect of temperature on galvanically induced hydrolysis of graphite/BMI composite in 3.5 percent sodium chloride solution.

摘要

A study was conducted to evaluate the effect of temperature on galvanically induced degradation of graphite reinforced bismaleimide composites (Gr/BMI) when coupled with an aluminum alloy in a 3.5% NaCl solution. Electrochemical measurements revealed potential differences as high as 800 mV. Potential differences provide the driving force for corrosion. Current increases exceeding 400 percent were measured and relate directly to increased corrosion intensity. Flexural test data indicated a significant loss in strength and stiffness after short periods of exposure to elevated temperatures. Destructive evaluation revealed that hydrolysis damage of the composite electrodes was also dependent upon temperature and after extreme exposures (180{dollar}spcirc{dollar}F for 12 days) was found to exist in as much as 40% of the composite thickness. Further microscopic evaluation of damaged specimens revealed cracking within the damaged zones of the composite electrodes indicating that a mechanical factor may also contribute to the rate of degradation.