Study on Initial Corrosion Behavior of GH907 Superalloy in Neutral Salt Spray Environment

GH907 superalloy has been widely used in aircraft，ship and other industries.Because GH907 superalloy will be corroded when used in marine environment， it is necessary to study its corrosion behavior.In this work， the corrosion behavior of GH907 superalloy material in simulated marine environment was studied by neutral salt spray test.The 2D and 3D morphology of GH907 superalloy after corrosion were observed by means of scanning electron microscope (SEM)，X-ray energy dispersive spectroscopy (EDS) and 3D confocal laser scanning，and the composition of GH907 superalloy was analyzed.Moreover，the electrochemical corrosion behavior of GH907 superalloy was analyzed through electrochemical tests of potentiodynamic scanning and electrochemical impedance spectroscopy.Results showed that GH907 material would undergo passivation behavior during neutral salt spray corrosion.After corrosion， the corrosion current density of GH907 increased， the corrosion resistance decreased， and the corrosion products and passivation film possessed limited ability to protect the material.Furthermore， the main corrosion type was pitting corrosion.EDS results revealed that the corrosion products in the pitting pits were mainly Fe oxides， with very low Ni and Co element contents.Besides， the charge transfer and diffusion behavior existed in the corrosion process， and the corrosion system was an activation control system.