Wear-reducing nickel-phosphorus and graphene oxide-based composite coatings: Microstructure and corrosion behavior in high temperature geothermal environment

Polymer coating modified with graphene oxide (GO) and duplex electroless Nickel-Phosphorus (Ni-P) with polytetrafluoroethylene (PTFE) coating were investigated for their corrosion behavior in simulated high-temperature geothermal environments with/without H2S and CO2 gases for geothermal applications. The polymer coating with added GO nanosheets demonstrated low wetting ability and suppressed corrosion effects of the substrate at 120 °C. The Ni-P/PTFE duplex coating with the lowest P content was suitable in an H2O liquid environment at 120 °C while high P was more promising in the two-phase CO2/H2S environment. Nevertheless, all the coatings were unprotective and allowed substrate corrosion at 250 °C in the H2S/CO2 environment.