Corrosion and wear-corrosion resistance properties of electroless Ni-P coatings on GFRP composite in wind turbine blades

Electroless nickel (EN) coatings with phosphorus are preferred in many industries such as the oil, chemical, plastic, mechanical, and electronic industries because of their excellent corrosion and wear resistance. This work evaluates the corrosion and wear-corrosion resistance of electroless nickel-phosphorus (ENP) coatings on glass fiber-reinforced plastic (GFRP) composites that are frequently used in wind turbine blades. The results demonstrated that the micro-porosity, phosphorus content, thickness and corrosion and wear-corrosion properties of ENP coatings on the GFRP substrate were all strongly related to the grinding pretreatment condition, meaning the corresponding surface roughness state of the substrate. A higher P content (P >7 wt.%), lower micro-porosity, greater thickness and greater hardness of the ENP coatings on GFRP substrate were obtained as the surface roughness of the substrate increased over 0.3 mu m (as it did upon grinding with emery paper of lower than 800-grade), improving corrosion and wear-corrosion resistance properties. (C) 2008 Elsevier B.V. All rights reserved.