Preparation Of Zn-Al Layered Double Hydroxides And The Study Of Anti-corrosion Property

Layered double hydroxides（LDHs）was a new anti-corrosive material with unique layered structure.In this paper,LDHs was taken as the research object to improve the anti-corrosion performance of materials from two aspects of reducing the aggregation of LDHs and ICPs.Zn Al-LDHs was compounded with PANI,PPy,GO and RGO.The electrical conductivity was improved on the basis of keeping the anticorrosive property of the composite materials.（1）LDHs and LDO were prepared by coprecipitation method,hydrothermal method,urea hydrolysis method and calcination reconstruction method.The electrochemical properties of LDHs films on 304 stainless steel were studied by sol-deposition and electrochemical deposition method.The results show that the corrosion properties of LDHs films prepared by different methods was different.By coprecipitation method in combination with sol deposition method,LDHs film,the concrete preparation conditions of zinc nitrate and aluminum nitrate of amount of substance ratio of 2:1,p H of 10,65℃water bath aged 24 h.FT-IR showed that the structure of LDHs powders contained a large amount of-OH,CO₃^2-and M-O,M-O-M and O-M-O.XRD showed that LDHs crystal structure was relatively simple with few impurities.TG showed that LDHs material contained about 5wt%crystal water.SEM shows that the microstructure of LDHs was hexagonal.（2）GN-LDHs were prepared by coprecipitation method with GN.GN-LDHs films were prepared on 304 stainless steel by sol-deposition method.The results show that when the mass ratio of GO,RGO and LDHs as 1:5 and 1:30,the films anti-corrosive performance were optimal.The film of GO-LDHs impedance of2.888×10⁴Ω,anti-corrosion performance was better than the LDHs and LDO films.SEM showed that lamellar LDHs adhere to in the GN layer.（3）Introduced by in situ polymerization,chemical conductive polymer made ICPs-LDHs,ICPs-LDHs films were prepared on 304 stainless steel by sol-deposition method.When the monomer of ICPs and LDHs mass ratio as 1:5,the film anti-corrosive performance were optimal,PANI-LDHs film impedance as 6.816×10⁴Ω,anti-corrosion performance was better than the LDHs and LDO films.SEM showed that the ICPs coated the lamellar of LDHs.（4）With An,Py and GN-LDHs prepared by coprecipitation as raw material,adopted chemical in-situ polymerization of ICPs-GN-LDHs.ICPs-GN-LDHs films were prepared on 304 stainless steel by sol-deposition method.When the monomer of ICPs and GN-LDHs mass ratio as 1:5,the films anticorrosive performance were optimal,PANI-GO-LDHs film impedance of 8.502×10⁴Ω,anti-corrosion performance better than the GN-LDHs and ICPs-LDHs composite material.SEM showed that the ICPs coated the lamellar of GN-LDHs.