Modification Of Zinc Powder And Titanium Dioxide And Its Effect On Anticorrosion Performance Of Epoxy Coating

Epoxy resin has been widely used in the field of coatings due to their excellent corrosion resistance,permeability resistance and adhesion ability,but they are difficult to meet the requirements in harsh environment leading its anticorrosion effect limited to a certain extent.Various fillers are usually added to the resin to improve the anticorrosion performance of epoxy coating,but the dispersion stability and interface compatibility between inorganic fillers and epoxy resin are poor.This article uses the high temperature mechanical force to complete chemical surface modification of zinc powder and titanium dioxide,making its surface better grafting epoxy resin molecule and bonding with the epoxy resin molecular so as to solve problems of poor compatibility and dispersion in the epoxy resin and to explore how the modified zinc powder and titanium dioxide respectively affect the performance of anticorrosive epoxy coating.Zinc powder was modified at grinding speed of 2010 r/min with the grinding time at 5hours and modification temperature at room temperature,80℃,100℃,120℃and 140℃,respectively.It was found that the zinc powder modified at 120℃had better surface hydrophobicity,dispersion stability in epoxy organic solution and modification effect than other groups,so 120℃was the best modification temperature.60%of the zinc coatings were fabricated by adding the zinc powder before and after the modification into the epoxy system.It was founded that the Zn powder distribution under the120℃was the best according to the observation of the cross-section of the coating.Results showed that the modified zinc powder on the epoxy coating anticorrosion performance did not improve by adhesion test、neutral salt spray test and bibulous rate test.The reason is that the modified zinc powder changes from ball to sheet,and is disordered in the coating,which increases the interface defects of the coating,leading to its anti-corrosion performance is not as good as that of the unmodified zinc powder coating.Under the conditions of grinding speed of 2010 r/min,modification temperature of 120℃and modification time of 1 h,3 h,5 h and 7 h respectively were performed to titanium dioxide.The contact Angle,settlement,TG and FR-IR tests of the powder before and after modification were carried out.It is found that the Ti O₂ modified for 3h has the largest contact angle,best dispersion stability in epoxy and modification effect,so the optimal modification time is 3h.The Ti O₂/epoxy coatings were fabricated by adding the Ti O₂ before and after modification to the epoxy system making it containing 4%of the mass of epoxy resin.It can be concluded that the modification time for 3 h coating of titanium dioxide is better than other coating from the coating section microscopic morphology,adhesion and water absorption test results,the titanium dioxide coating with modification time of 3 h has excellent anticorrosion performance compared with other coatings based on the results of open circuit potential and the analysis of the results of electrochemical impedance test.