Preparation And Anticorrosive Performance Of Rare Earth Doped Silica Nanocontainers

Corrosion inhibitor-loaded smart nano-containers play an increasingly important role in the field of metal anti-corrosion,which can realize the loading,encapsulation and responsive release of corrosion inhibitors.In addition,rare earth metal salts have been proven to be good corrosion inhibitors and are environmentally friendly,which play an important part by reducing the cathodic oxygen reduction reaction,and their application in corrosion protection is becoming more and more extensive.In order to combine the advantages of the two,in this work,two kinds of rare earth doped silica nanocontainers were prepared by two different methods.Then the vacuum loading technology was used to load the inhibitor,and the nano valve was installed to prevent the leakage of the inhibitor.The release behavior of the corrosion inhibitor was analyzed through the release kinetic process,and finally the electrochemical method was used to study the corrosion inhibition performance of the intelligent corrosion inhibition system in the corrosive medium,and clarified the responsive release behavior of the corrosion inhibitor and the intelligent corrosion inhibition mechanism.This research has important guiding significance for the realization of the application of corrosion inhibitor-loaded smart nano-containers in the intelligent anti-corrosion of metals.First of all,method one is to prepare La-HMSN nanocontainer by hydrothermally and to to prepare Ce-MON nanocontainer by the one-step template way.Through scanning electron microscope,transmission electron microscope,nitrogen adsorption and desorption,solid nuclear magnetic resonance,Fourier infrared spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy and other characterization methods to study the microscopic morphological structure and frame composition of the two kinds of nanocontainers.The results show that La-HMSN is hollow nanosphere and Ce-MON is a nanosphere with dendritic pores.Both of them have high specific surface area and pore volume.The specific surface area of La-HMSN is 160 m²·g^-1 and the pore volume is 0.24 m³·g^-1.Ce-MON has larger specific surface area(676 m²·g^-1)and pore volume(0.60 m³·g^-1).La is doped in the framework of La-HMSN and exists in the form of La₂Si₂O₇ and La₂Si O₅.Ce in the Ce-MON exists in the way of adsorption near the O atom on[C-Si（OSi）₂OH]through coordination.Next,benzotriazole（BTA）inhibitor was loaded by vacuum loading technology to obtain intelligent nano containers（BTA/La-HMSN,BTA/CE-MON）loaded with inhibitor.The final product（BTA/La-HMSN@PDA,BTA/Ce-MON@PDA）was obtained by installing nano valve polydopamine（PDA）.The loading amount of BTA and the installation of nano valve were studied by thermogravimetric analysis,nitrogen adsorption and desorption and Fourier infrared spectroscopy.The results show that the loading capacity of BTA/La-HMSN@PDA and BTA/Ce-MON@PDA is about 19%and 35%respectively.In addition,UV-vis spectrophotometry and liquid chromatography were used to study the responsive release performance of BTA/La-HMSN@PDA and BTA/Ce-MON@PDA unde under different p H conditions.The experimental results show that the cumulative release of inhibitor increases with the decrease of p H value,and the release of corrosion inhibitors hardly occurs under neutral conditions.Finally,the intelligent corrosion inhibition performance of BTA/La-HMSN@PDA and BTA/Ce-MON@PDA on steel sheets in 3.5 wt.%Na Cl solution was studied through electrochemical impedance spectroscopy and polarization curves,and the corrosion morphology of the steel sheet was analyzed by scanning electron microscope,X-ray energy spectrum etc.The results show that when BTA/La-HMSN@PDA and BTA/Ce-MON@PDA increase to a certain concentration,the corrosion inhibition effect increases with the increase of the concentration.When the concentration is too low or exceeds the critical concentration,corrosion will be accelerated.The best concentration of BTA/La-HMSN@PDA is 0.08 g·L^-1;the best concentration of BTA/Ce-MON@PDA is 0.04 g·L^-1;the corrosion inhibition effect of the steel sheet added with BTA/La-HMSN@PDA is better than that of BTA/Ce-MON@PDA.