Effect Of Plasma Treatment On The Properties Of Epoxy Resin Coatings

Epoxy resin coatings are widely used in the field of corrosion due to the excellent mechanical properties,low shrinkage after curing,good corrosion resistance and good heat resistance.However,the application of epoxy coating is seriously limited by the poor bonding strength between epoxy coating and substrate,the easy falling off of epoxy coating under external force or special environment,and the poor anti-aging performance of the coating.Therefore,the epoxy coating was prepared by low temperature plasma spraying.The surface of epoxy resin and the surface of epoxy resin were modified by the highly active groups in plasma to improve the bonding strength between the coating and the substrate,and to further improve the other properties of the coating.The modification mechanism was studied by modern analytical methods such as XRD,AFM and infrared spectroscopy.The thickness,hardness,porosity,wear resistance and corrosion resistance of the coating were analyzed,and the changes of coating properties were studied in ultraviolet and hygrothermal aging environment,which provid the basis for the preparation of high strength epoxy resin coatings.The results show that the use of air,N2 and O2 plasma treatment on steel substrate promote the oxidation of Fe2O3 and Fe3O4 oxides on substrate surface,oxygen content on substrate surface treated by O2 was higher than air and N2.The oxide increases the surface roughness of the substrate,roughness of substrate surface treated by 02 was 72.80 nm,3 times than the surface without any treatment.The polarity surface energy and dispersive surface energy of the substrate surface were improved.The maximum surface energy after O2 plasma treatment was 66.77×10-3N/m,which was 61.1%higher than that of untreated surface.After plasma treatment,some groups such as-OOH were successfully introduced on the surface of steel substrate,and the functional groups such as C=O,C-O,and-OH were obviously increased after plasma treatment of epoxy resin powder.Based on the change of the properties of the steel substrate and epoxy powder,the bonding strength between the epoxy coating prepared by plasma spraying and the steel substrate has been greatly improved.The binding strength was 4.25Mpa,6.64Mpa,and 7.51Mpa treated with air,N2 and O2 for 2 min,which was increased by 2.5,3.9,and 4.5 times than that of untreated 2min.Under the same powder content and the same preparation conditions,the thickness,density,wear resistance and corrosion resistance of the coating prepared by plasma were improved,and the properties of the coating after O2 plasma treatment were higher than those of air and N2 plasma treatment.The results of ultraviolet and hygrothermal aging for two months showed that the bonding strength between the coating and the substrate could be improved by plasma treatment.The bonding strength of 2min treated with O2 plasma was increased to 4.30Mpa and 2.57 MPa,respectively,and the effect was the best.