Corrosion Of Important Anions In The Rivers Of Sichuan To Typical Steel Used In Hydraulic Turbines And Its Coating Protection Research

Turbine blades,vanes and over-current components are immersed in water for a long time,which is prone to production accidents and economic losses.At present,there is still little research on the corrosion resistance of steels commonly used in hydraulic turbines,especially the discussion on the synergistic corrosion law of different anions in simulated river water.Therefore,for 45#carbon steel and 0Cr18Ni9Ti stainless steel for turbines,explore the synergistic effect of typical anion corrosion and improve the traditional aqueous anti-corrosion coating by graphene modification which has theoretical and practical significance.The samples in hydropower station were taken for chemical analysis.The effects of typical anion synergy on the corrosion behavior of 45#carbon steel and 0Cr18Ni9Ti stainless steel were investigated by electrochemical method.It shown that in the simulated river water with Cl-,HCO3-and SO42-,the corrosion process of the two steels is controlled by the cathodic reduction reaction.When the content of Cl-increased from 0.4g/L to 1.2g/L,the corrosion rate of 45#steel increased,while the increase of SO42-had the inhibition effect on the corrosion of 45#steel.From the study of the corrosion behavior of 0Cr18Ni9Ti stainless steel by typical anion synergy,From the study of typical anion synergy of 0Cr18Ni9Ti stainless steel,it can be concluded that HCO3-promotes the corrosion of stainless steel within a certain range.The increase of SO42-in a certain range has the effect of inhibiting corrosion,and the increase of Cl-content within a certain range shows the law that inhibition at first and then promotion when Cl-reach a certain concentration.When the Cl-concentration is 1.2g/L,the corrosion rate reaches a minimum of 1.4937×10-9 mmpy.As the Cl-concentration continues to increase,the corrosion rate increases rapidly.The corrosion process of both steels is controlled by the cathodic reduction reaction.45#carbon steel is uniformly corroded and OCr18Ni9Ti is mainly pitting corrosion;under the synergy of HCO3-,Cl-,SO42-,the final corrosion products of 45#carbon steel are FeO(OH),Fe6(OH)12CO3,Fe3O4,and the corrosion products of OCr18Ni9Ti stainless steel are iron oxides,chrornium compounds and sulfides.The formulation of the waterborne heavy anti-corrosion protection system coating was optimized by using graphene to modify the aqueous heavy-duty anti-corrosion coating.After the immersion experiment in simulated water,the performance of the coating was analyzed by means of electrochemical workstation and scanning electron microscope.It shown that when the content of zinc-rich zinc-based primer zinc powder was 40 wt%,the content of graphene was from 0 wt%increased to 0.6 wt%,and the corrosion rate first decreased and then increased.When the graphene content reached 0.6 wt%,the corrosion current reached a minimum of 4.58×10-8?A·cm2.When the content of cloud iron powder in the epoxy cloud iron intennediate paint is 15 wt%,the corrosion rate decreases first and then increases with the graphene content from wt 0%to 0.6 wt%.When the graphene content reaches 0.2%,the corrosion occurs.The current reaches a minimum of 2.3060×10-7?A·cm-2.As the graphene content increases,the adhesion of the coating increases.As the graphene content increases,the hardness of the epoxy zinc-rich coating decreases,while the hardness of the epoxy cloud iron coating increases.In the investigation of the influence of temperature on the waterborne heavy-duty anti-corrosion coating.And it can be seen from the salt spray test that adding a proper amount of graphene can replace some of the metal filler in the coating,and does not affect the corrosion resistance of the coating within 1000 hours.