Preparation On The General Volatile Corrosion Inhibition Film And Research Of Corrosion Inhibition Mechanism

In this paper, Preparation of general volatile corrosion inhibition film for the corrosion of metals in the atmosphere is presented, corrosion inhibition mechanism of volatile corrosion inhibition in liquid membrane is studied. First, electrochemical tests on volatile corrosion inhibition compound is carried out by the electrochemical workstation(Tafel polarization curve) and impedance spectroscopy (EIS).Corrosion inhibition rate of Q235 steel and brass in sodium chloride solution is studied,the best compound ratio of volatile corrosion inhibition is obtained. Secondly, volatile corrosion inhibition film is made by the best compound ratio of volatile corrosion inhibition through coating, and heat and humidity tests are carried out in a constant temperature and humidity chamber with high temperature and humidity. The corrosion mechanism of volatile corrosion inhibition and effect of temperature and Cl concentration on volatile corrosion inhibition is studied.The electrochemical experiments results show that 3.5% NaCl solution containing ammonium molybdate, triethanolamine, sodium benzoate and zinc sulfate corrosion inhibition can decrease the corrosion rate of Q235 steel and brass apparently when the concentration ratio of quanternary compound ratio volatile corrosion inhibition is 2g/L:8g/L:10g/L:4g/L,and the corrosion inhibition rate to Q235 steel is 90.78 %, to brass is 87.65%,it has well corrosion inhibition effect.The heat and humidity test results show that the corrosion inhibition rate of quanternary compound ratio volatile corrosion inhibition to Q235 steel is 87.34 %, and to brass is 86.56%,it has well corrosion inhibition effect consistent with the electrochemical experimental results. There is a synergistic effect between the various components of quantemary compound volatile corrosion inhibition, corrosion inhibition effect has improved significantly compare with single component.The metal characterization results show that compound volatile corrosion inhibition is a mixed corrosion inhibitor for Q235 steel, it inhibits the electrochemical reaction of the anode and cathode of carbon steel.The lone pair electrons of N and O atoms of volatile corrosion inhibition and d orbital of Fe are bonding with coordination bond , and it forms adsorption film on the surface of Q235 steel, volatile corrosion inhibition prevents formation of ferric oxide and other corrosion products on surface of Q235 steel from EDX, and adsorption film is hydrophobic, and corrosion inhibition rate increases slightly with the increase of temperature and the decrease of Cl- concentration. The compound volatile corrosion inhibition film mainly inhibited the anodic corrosion reaction for brass. On the surface of brass, N atoms of volatile corrosion inhibition interacts with Cu molecules to form a thin protective film, volatile corrosion inhibition prevents formation of Cu(1),Cu2O and other corrosion products on surface of brass from EDX, and the protective film is hydrophobic. corrosion inhibition rate reaches the maximum when the temperature is the range from 50 ～ 60 ℃ ,and corrosion inhibition rate increases with the decrease of Cl- concentration.