Effect Of Zinc And Aluminum Ions On The Properties Of Oxide Film Formed On 304L Stainless Steel In High Temperature Water

304L stainless steel is an important structural material for the primary circuit of a nuclear power plant.The corrosion and cracking of this metal can cause safety problems and increase the economic efficiency of the nuclear power plant.Therefore,studying the corrosion protection technology of 304L stainless steel and reducing the radiation dose of the primary circuit is of great significance for the operation and development of nuclear power plants.In this study,by simulating the water environment of the primary circuit of a nuclear reactor,on the basis of zinc injection technology,different concentrations of aluminum ions were added,and the zinc ions and aluminum ions were divided into 10 different concentrations and combined with each other,using the high temperature and high pressure in the reactor.304L stainless steel is processed under conditions,and then electrochemical and photoelectrochemical techniques are used to detect the corrosion resistance parameters and phase composition of the oxide film formed on the metal surface.304L stainless steel is soaked in 290?solution for 7 days to form a passivation film,and the corroded metal is tested in boric acid buffer solution(PH=8.4)for potentiodynamic scanning,Mott-Schottky curve,AC impedance and photocurrent response,and then passed The polarization curve and the calculation formula are used to obtain the corrosion current density and corrosion potential.The semiconductor type,flat band potential and carrier concentration are obtained by the Mott-Schottky curve and the semiconductor type calculation formula.Obtain the oxide film structure and the impedance value of the oxide film through AC impedance spectroscopy and software data fitting,and obtain the band gap potential through the photocurrent test and the relationship diagram between(i_ph?hv/I₀)^1/2 and photon energy,and then The phase composition of the oxide film is judged,and the influence of zinc ions on the corrosion of 304L stainless steel is judged by the obtained metal corrosion resistance parameters and photocurrent test.After reading a lot of literature,it can be determined that the corrosion current density of the polarization curve can reflect the corrosion resistance of the metal,and the smaller the corrosion resistance of the metal,the better.The carrier concentration of the Mott-Schottky curve can be based on the point defect model.The carrier concentration of the oxide film on the metal surface is directly related to the stability of the oxide film,and the corrosion resistance of the metal has a very large relationship with the oxide film.,The smaller the carrier concentration of the oxide film,the better the stability of the oxide film,so it is less likely to be destroyed.From this,the optimal concentration of zinc and aluminum ion implantation can be determined.AC impedance and photocurrent detection clarified the structure and phase composition of the 304L stainless steel oxide film,and the oxide film has a double-layer structure and film impedance value through software simulation.The photocurrent test determines the phase composition of the oxide film,and uses thermodynamic analysis to understand the nature of the phase to explain the reason for the enhanced corrosion resistance of the metal.