Cavitation Erosion Behavior of Epoxy-, Vinyl ester-, and Phenolic-based Fiber Glass Composites in Sea Water

The cavitation erosion behavior of three fiber glass reinforced epoxy, vinyl ester and phenolic in sea water was investigated using an ultrasonically induced cavitation facility. The cavitation tests were made at a frequency of 20 KHz as per ASTM-G30-90 and at temperatures of 25⁰C and 50⁰C. Cavitation increased the rate of mass loss of these three fiber glass reinforced plastics by several orders of magnitude with respect to stagnant conditions.  Cavitation made the surface of these three fiber glass reinforced plastics to appear very rough, exhibiting large cavity pit in the region of the attacked area as revealed by the scanning electron microscope (SEM).  The main mechanisms of failure for the three systems were due to loss of adhesion of the matrix / fiber glass interface and subsequent removal of the resin as well as glass fibers by the mechanical action of cavitation or erosion. Mechanical factors and surface defects were determined to be the leading cause of resin and glass fiber loss.