Study On The Corrosion Inhibition Characteristics And Application Of Metal Organic Frameworks(MOF)

Metal-organic frameworks(MOF)are novel organic-inorganic hybrid materials that rely on metal ions as the center to form coordination bonds with organic ligands.These materials are characterized by large specific surface area,high porosity and multiple active sites which have broad application prospects in the field of metal corrosion protection.In this thesis,a new type of Cu-MOF was synthesized as corrosion inhibitor for carbon steel in hydrochloric acid,and the synergistic corrosion inhibition effect between Cu-MOF,thiourea and hexamethylenetetramine was further explored.At the same time,BTA was encapsulated in MOF-5 to prepared BTA@MOF-5 composite material that can slowly release BTA corrosion inhibitor.Then,epoxy coating doped with BTA@MOF-5 was tested by comprehensive measurements to investigate the composite coating anti-corrosion performance.The main research contents are as follows:Cu-MOF was prepared by solvothermal method with Cu²⁺as the metal ion and5-methylthiophene-2-carboxylic acid as the organic ligand.The corrosion inhibition effect of Cu-MOF for carbon steel in hydrochloric acid was evaluated by weight loss experiment and electrochemical test.The experimental results showed that Cu-MOF,as a mixed-type corrosion inhibitor,could significantly inhibit the corrosion of carbon steel in HCl.When the Cu-MOF concentration was 50 mg/L,the corrosion inhibition efficiency reached82.4%.From XPS analysis,SEM and AFM morphology observation,it can be seen that Cu-MOF can form hydrophobic film on the surface of carbon steel through S atom.This film covered the metal surface to prevent corrosion by shielding the active sites of the corrosion reaction on carbon steel.The compounding study of Cu-MOF,thiourea and hexamethylenetetramine found that when the concentration of compound corrosion inhibitor was 50 mg/L,the best compounding ratio of Cu-MOF and thiourea was 4:1,and the corrosion inhibition efficiency reached 92.1%.When the compound ratio of Cu-MOF and hexamethylenetetramine was 2:3,the corresponding corrosion inhibition efficiency reached 92.9%.Between these two substances and Cu-MOF had good synergistic corrosion inhibition effects.It is derived from the fact that small molecule thiourea can fill the gaps in the protective film formed by Cu-MOF on the surface of carbon steel,and hexamethylenetetramine can cover the active sites of metal corrosion reaction.Using MOF-5 as the BTA corrosion inhibitor carrier,the BTA@MOF-5 composite material was prepared,and its micromorphology and loading characteristics were investigated by SEM,TEM,XRD,FTIR and TGA tests.In addition,UV-vis and electrochemical tests confirmed the slow release characteristics of BTA@MOF-5.The concentration of BTA in the solution gradually increased with time,and the corrosion inhibition efficiency also increased.The analysis of EIS monitoring and neutral salt spray tests indicated that the corrosion resistance of epoxy coating doped with BTA@MOF-5was improved,and the released BTA corrosion inhibitor can protect the exposed pure copper substrate,thereby effectively improving the anti-corrosion performance of epoxy coating.