WPTO held its first webinar in the WPTO R&D Deep Dive Webinar Series. Francisco Presuel-Moreno, professor in the ocean and mechanical engineering department at Florida Atlantic University, presented on crevice corrosion in seawater using CFRP/hybrid composite as part of a novel crevice former.
Marine hydrokinetic (MHK) devices for renewable energy power generation are fully or partially immersed in seawater while in service. MHK devices sometimes are made of composites and a variety of alloys. The composite type used is sometimes carbon fiber reinforced polymer (CFRP) composites, other times fiber glass reinforced polymer (GFRP) composites are used. In some cases, the composites are fastened using metallic hardware. The fastened composites can cause tight occluded regions that later could become crevice corrosion on the fastened metal regardless of the type of composite. A modified crevice former was used to investigate crevice corrosion for fastened samples immersed in seawater using CFRP/hybrid composite plates. Three alloys were investigated: 316 stainless steel, Monel and Titanium alloy. Selected samples were removed for visual examination and dis-assembled after more than 270 days (up to 810 days). Crevice corrosion and pitting corrosion was found on the stainless steel and Monel hardware, and corrosion extent increased with time.