A study on properties of corrosion fracture surfaces of GFRP in synthetic sea water

Abstract

In this paper we investigate the stress corrosion cracking (SCC) mechanism and the properties of the corrosion fracture surface of glass fiber reinforced plastics (GFRP) produced by hand lay-up (HLU) in synthetic sea water. The test material is a GFRP with vinylester type epoxy acrylate resin (an unsaturated polyester) as the matrix and chopped strand mat (CSM) type E-glass fiber as the reinforcement. The slow strain rate test (SSRT) was perormed on dry and wet specimens in air and sea water. Here the pH concentration of synthetic sea water was controlled to 6.0, 8.2 and 10.0, and the strain rates varied from 1×10−4 (sec−1) to 1×10−7 (sec−1). The results confirm the fact that in wet specimens tested at a particular strain rate, evidence of SCC such as co-planar, mirror and hackle zone appear. Moreover, stress corrosion of GFRP in sea water was characterised by flat fracture surfaces with only small amounts of fiber pull-out.