Corrosion and Electrochemical Behavior of Boron/Aluminum Composites^★(1)

Electrochemical measurements in 3.5% NaCl solution at room temperature indicated that there was no galvanic interaction when virgin boron fibers were coupled to aluminum. In contrast, boron fibers, extracted from a boron/aluminum composite, containing an aluminum boride intermetallic on the surface (produced during high temperature fabrication), showed a galvanic current flow when coupled with aluminum. Therefore, galvanic corrosion would be expected between the aluminum boride intermetallic and the aluminum matrix causing preferential attack of the aluminum. Corrosion potential, galvanic current, and polarization measurements verified this conclusion.