| Coating protection is one of the most simple and effective methods to deal with metal corrosion.At present,epoxy resin?EP?has become one of the most widely used coating substrates due to its excellent properties,but it also has some disadvantages such as high brittleness,poor toughness and short anticorrosion time,so it can be modified by adding nano fillers.Graphene oxide?GO?,a two-dimensional lamellar material with a large number of active functional groups on its surface,has good mechanical properties and chemical stability,and has attracted much attention in the field of composite materials.However,the huge specific surface area and van der Waals forces between molecules reduce the dispersion of GO,affecting its further application.In order to solve the above problems,this paper uses two methods,covalent grafting and hydrothermal synthesis are used to modify GO and prepare GO-Ti and RGO-Ti O2 nanocomposites.Finally,the composites are added to EP to prepare GO-Ti/EP and RGO-Ti O2/EP composite coatings.The structure of the composite and the properties of the composite coating are studied,and the conclusions are as follows:?1?The test results show that the two modification methods for GO are successful.Ti and Ti O2 nanoparticles are successfully and evenly loaded on the GO sheet,which changes the structure of GO.Compared with GO 0.81nm lamellar spacing,GO-Ti lamellar spacing increased to 1.02 nm,RGO-Ti O2 composite lamellar size decreases,the state is more dispersed.It shows that the loading of nanoparticles changes the multi-layered close-packed structure of graphene oxide into a thin layer loose structure;?2?The sedimentation experiment shows that when the sedimentation experiment is carried out to the 7th day,GO/EP completely sedimented,while GO-Ti/EP and RGO-Ti O2/EP are still uniformly dispersed when the experiment was carried out for 70 days.Combining the results of the fracture surface scanning,it can be concluded that GO-Ti and RGO-Ti O2 exhibit excellent dispersibility and compatibility in epoxy resins.?3?The results of electrochemical experiments show that after immersion for 192h,GO-Ti/EP reaches the middle stage of corrosion,and the impedance modulus in the low-frequency region is an order of magnitude higher than GO/EP,showing excellent corrosion resistance.After 168 h salt spray experiment,the corrosion spread of GO-Ti/EP and RGO-Ti O2/EP composite coating at the cross is only 1 mm,which is better than that of GO/EP coating.This shows that GO-Ti and RGO-Ti O2 have good compatibility with epoxy resin,which can form a"labyrinth effect"to prevent the penetration of corrosive media,extend the path of the corrosive media,and reduce the corrosion rate.?4?The mechanical property research shows that GO-Ti/EP and RGO-Ti O2/EP composite coating can withstand 30 kg/cm impact;compared to pure EP,the adhesion of GO-Ti/EP and RGO-Ti O2/EP composite coating is improved by 4 levels after being boiled;the average friction coefficient of GO-Ti/EP is reduced by 0.34;the wear value of RGO-Ti O2/EP is reduced by 0.034 g.The modified GO composites effectively improve the mechanical properties of the coating.This shows that GO-Ti and RGO-Ti O2 can play a supporting,lubricating and thermal conduction role on the surface of the coating,and they can play the matrix yielding effect,pinning-crack effect and two-phase interface effect inside the coating,which improves the strength,toughness and wear resistance of the coating. |
PDF Full Text Request