Microstructural Characterization, Corrosion and Wear Properties of Graphene Oxide Modified Polymer Coatings for Geothermal Drilling Applications

摘要

Polymeric coatings are exploited by adding reinforcements to maximize its industrial performance. The idea of reinforcement is to tailor the matrix's wide-range performance to a specific desired property to prevent component failures. In this work, the polyphenylene sulfide-polytetrafluoroethylene (PPS-PTFE) matrix was modified with graphene oxide (GO) to improve the mechanical properties, corrosion and wear resistance, to provide coatings for drilling components for high-temperature geothermal well environment. Electrochemical test in a 3.5wt% NaCl solution and a pin-on-disc sliding test were performed to determine the corrosion and wear resistance of the novel coatings. The addition of GO reduced the coefficient of friction but increased the roughness and hydrophobic properties of the coatings. The tendency of coatings to minimize corrosion were determined by evaluating the open circuit potential (OCP), corrosion potential (E_(corr)) and corrosion current density (I_(corr)). The coatings showed higher OCP, E_(corr) and lower I_(corr) after 24 hours of immersion. The 1wt% GO polymer coating is the most promising; based on the reduction of I_(corr)- of the substrate from 0.15 μA to 0.01 μA and an increased friction and wear resistance by approximately 72%. The results indicate a good coating performance for low GO reinforcement by improvement in surface properties, corrosion and wear resistance.