Studies On Anti-corrosion Behaviors Of Electroless Deposited Ni-p And Ni-p-ptfe Coatings In Seawater

Electroless deposited nickel-phosphorus coatings have been widely applied in many industries, such as chemical engineering, mechanical and electronic engineering, etc. due to their good anti-corrosion properties and wear resistance. In order to develop applied range of the coatings, some other particles were mixed in the plating bath to obtain composite coatings with more outstanding capability. Polytetrafluoro-ethylene (PTFE) is chemically very inert. PTFE also has non-stick property due to its low surface energy. The incorporation of PTFE nanoparticles into the Ni-P matrix can take advantage of the different properties of Ni-P alloy and PTFE. The Ni-P and Ni-P-PTFE coatings with different PTFE particiles concentration were electroless prepared on carbon steel in this study. The micromorphology, element composition and distribution, and phase composition of the coaings were studied by scanning electron microscope (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD). The corrosion resistance of the Ni-P and Ni-P-PTFE coatings in natural seawater and steriled seawater were researched by electrochemical impedance spectroscopy (EIS). The results showed that the Ni-P palting was quite dense. For the Ni-P-PTFE composite coatings, the PTFE content in the coatings increased with increasing PTFE concentration in the solution. The electroless deposited Ni-P and Ni-P-PTFE coatings were in an amorphous state. The corrosion resistances of the Ni-P and Ni-P-PTFE platings were better in steriled seawater than in natural seawater. With the PTFE concentration increasing in Ni-P-PTFE coatings, the corrosion resistance turned worse.