| Corrosion oxidation is one of the most important forms for the steel material failure.Therefore,the study of metal corrosion and protection is a great significance.The steel surface of hot-dip alloy layer can effectively improve the corrosion resistance of steel materials.So it has been widely applied to the production and life.Hot-dip alloy layer has been exposed under the natural environment for a long time.You need to take other processes to further corrosion.So the passivation process is coming into being.In this paper,This research is focused on the development of hot-dip galvanized aluminum-nickel rare earth alloy solution and the new chrome-free passivation solution on steel substrate.It aims to develop a new type of hot dip galvanized aluminum-nickel rare earth alloy solution for plating,which can reduce the coating defects and improve the surface quality of the coating.Which is on the basis of passivation treatment,it is further improving the corrosion resistance of the coating's surface.This paper is improving the corrosion resistance of steel materials by two main steps.First,it is the method of hot-dip alloy.The main process is as follows: Formulating a range of different levels of fluxing agent,fluxing performed under the same conditions,to eliminate the influence of other factors on the hot-dip process results.Through the analysis of the surface quality of the coating,the corrosion rate of the salt spray is compared with each other,the electrochemical polarization curves of each coating and the size of the corrosion current and the polarization resistance are analyzed to determine the coating with high corrosion resistance.The final results is in the best ratio of fluxing agent solutions of each component.The experimental results show that: 80g/500 ml ZnCl2+45g/500 ml NH4Cl+30g/500 ml SnCl2+0.3g/500 ml Urotropine+130g/500 ml absolute ethanol+350g/500 ml tetradecyl dimethyl benzyl ammonium chloride+200g/500 ml Alkylphenol polyoxyethylene ether is the best proportion of additive plating agent.Secondly,the effects of the content of cerium nitrate on the corrosion resistance of modified silane passivation film were studied.The concentration of cerium nitrate was taken as the variable.The modified silane passivation solution should been made of the adding amount of cerium nitrate about 0.0005mol/L,0.0007mol/L,0.001mol/L,0.003mol/L and 0.005mol/L which based on a variable with Cerium nitrate.The microstructural analysis of the passivation film was carried out.The following conclusions were obtained by the experiment of lead acetate and the electrochemical corrosion test.The best adding amount of the Cerium nitrate is about 0.001mol/L.When the content of cerium nitrate is less than 0.001mol/L,The corrosion resistance of the passivation film is increasing with the increase of the cerium nitrate content.When the content of cerium nitrate is higher than 0.001mol/L,the corrosion resistance of the passivation film is gradually deteriorating with the increase of cerium nitrate content. |
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