Preparation Of 06Cr19Ni10 Stainless Steel Corrosion Inhibitors In Sodium Chloride Medium

It is widely proved that stainless steel is the optimum material in water industry during the preparation,storage,transportation,purification,recycle,and seawater desalination.However,stainless steel are prone to have pitting corrosion in the solution contained Cl^-,so adding corrosion inhibitor to the solution is the most economical and convenient method.In order to protect the environment and save resources,this paper uses electrochemical method,measures the parameters of pitting corrosion potentials and protection potentials of 06Cr19Ni10 stainless steel in the 3.5%sodium chloride solution,and selects out several environment-friendly corrosion inhibitors,which have excellent inhibitory effects to the pitting corrosion in the sodium chloride solution(T=25℃).This paper selects sodium tungstate,sodium borate,glucose,and some amine compounds(FW) as the research objects.By using technical research methods of electrochemical polarization curves and electrochemical impedance,we study the corrosion inhibiting effect of stainless steel in the 3.5%sodium chloride solution,and analyze the mechanisms of it.The results show that:sodium tungstate,sodium borate, FW are anodic-type corrosion inhibitor,and glucose is a mixed prohibition inhibitor. The corrosion inhibiting effect of sodium tungstate is because the surface of stainless steel generates oxide film;the corrosion inhibiting effect of sodium borate is because the surface of stainless steel generates precipitation film;the corrosion inhibiting effect of glucose and FW is because the surface of stainless steel generates monolayer adsorption film.They all accord with Langmuir isothermal equation.The corrosion inhibition rate of each one-component corrosion inhibitor can not meet with the practical uses,so we remix these corrosion inhibitors and get a compound corrosion inhibitor(DWS) which have excellent corrosion inhibition effect. Then we evaluate all kinds of inhibition performances of this compound corrosion inhibitor.Under the conditions of different density of DWS,we use cyclic polarization curves and linear polarization technique,and measure all kinds of corrosion parameters of stainless steel in the sodium chloride solution;using electrochemical impedance spectroscopy,we measure the Nyquist plot of stainless steel in the sodium chloride solution which contain or not contain 100mg/L DWS. The results show that compound corrosion inhibitor DWS is a anodic-type corrosion inhibitor.When the density of it reaches to 100mg/L,the pitting corrosion potentials, protection potentials,and polarisation resistance of stainless steel increase tremendously,and the efficiency of corrosion inhibition reaches to 96.2%.The inhibition performance is because the surface of stainless steel generates monolayer absorption film,and the WO₄^2- and B₄O₇^2- in the film can absorb on the weak place of adsorption film in order to increase the compactness of absorption film which blocks the absorption of Cl^- on the surface of stainless steel.All of these increase the pitting corrosion resistance of stainless steel.