Study On Corrosion And Friction Resistance Of Zinc Oxide-graphene Oxide Reinforced Ceramic Coating

Due to the advantages of convenient coating process,environmental protection and low cost,inorganic bonded ceramic coating has become one of the main surface coatings to protect mechanical equipment from wear and corrosion.However,the brittleness of the inorganic bonding ceramic coating makes it poor in corrosion and wear resistance,and the carbon nano-reinforced material also has the problem of low bonding strength with the coating.Therefore,this paper uses graphene oxide（GO）as the reinforcing phase to improve the corrosion and friction properties of the coating.And by hybridizing zinc oxide-graphene oxide（ZnO-GO）nanomaterials,the bonding strength of the interface between GO and the coating is improved.The influence of ZnO-GO hybrid materials on the corrosion-friction properties of coatings was studied.Through the corrosion and friction interaction test,which provides a theoretical basis for the application and development of inorganic bonding ceramic coatings.Firstly,the ZnO-GO hybrid material was prepared by the sol method.The phase analysis and structure characterization of the ZnO-GO hybrid materials were carried out by SEM,XRD and FT-IR.The test results show that the ZnO hybridized on the GO sheet is uniformly distributed,the interlayer spacing of GO is increased,and the ZnO-GO hybrid material is successfully prepared.Secondly,the ZnO-GO hybrid material is added as a reinforcing phase to the inorganic bonding ceramic coating.It was characterized by XRD,SEM,DSC and other test methods.The results show that the ZnO-GO hybrid material is well dispersed in the coating and is firmly bonded to the coating.There are no new characteristic peaks in the coating,and ZnO-GO did not directly participate in the curing reaction.Nano-ZnO reacts with the binder to improve the bond between GO and the coating,making the coating more compact and denser.It can effectively enhance the hardness of the coating,slightly reduce the surface roughness,and slightly improve the contact angle.Next,the effect of ZnO-GO hybrid materials on the corrosion resistance of ceramic coatings was studied.The electrochemical corrosion test results show that:The corrosion current density of the coating with 0.5 wt.%ZnO-GO is one order of magnitude lower than that with 0 wt.%ZnO-GO.The frequency impedance at f_min=0.01 Hz is also improved,and the coating with 0.5 wt.%ZnO-GO is about 2.6 times higher than that of 0 wt.%ZnO-GO.The reason is that the coating has benefited from the addition of ZnO-GO hybrid materials and has obtained better surface quality.And ZnO-GO can effectively block the propagation of internal cracks and delay the penetration rate of corrosive media.Then,the influence of ZnO-GO hybrid materials on the wear resistance of ceramic coatings was analyzed.The tribological test results show that:The friction coefficient of the coating with 0.6 wt.%ZnO-GO decreased by 0.1 and the wear rate decreased by 75.3%.There are similar reasons when we consider that ZnO-GO can form a lubricating film on the surface of the wear scar and reduce the coefficient of friction.In addition,the ZnO-GO hybrid material improves the bonding strength between the coating and substrate,it also reduces the probability of the coating particles being pulled out during the grinding process.Therefore,the adverse effects of wear debris and wear rate of the coating are reduced.Finally,the influence of ZnO-GO hybrid materials on the corrosion and friction properties of ceramic coatings is discussed.Corrosion and friction interaction test results show that:The ZnO-GO hybrid material can increase the open circuit voltage of the coating in the corrosive and frictional state.The coating with the same content of ZnO-GO hybrid materials has a higher current density in the corrosive friction state than that in the static state.After the corrosion friction test,the impedance at f_min=0.01 Hz is lower than that before the test.The above shows that corrosion and friction will damage the coating.The coating without ZnO-GO hybrid material has the highest wear volume under the corrosive friction state.When 0.6 wt.%ZnO-GO is added,the total wear volume of the coating is reduced by 86%.In order to better study the synergistic effect of corrosion and wear,the loss of coating material caused by different factors was calculated.The calculation results show that the wear loss promoted by corrosion plays a leading role in the corrosion friction,and corrosion will accelerate the damage of the coating by mechanical friction.The addition of ZnO-GO hybrid material can effectively improve the corrosion resistance of the coating.This is due to the sol-gel process of the ZnO-GO hybrid material to form a network structure with GO as the core,which improves the forming quality of the coating.Therefore,the probability of failure and peeling of the coating due to corrosion friction is reduced,and the coating has the ability to resist corrosion ions.The unique sheet structure and high strength toughness of GO also make it difficult for the cracks generated by corrosion friction to spread inside the coating.Therefore,it can effectively extend the path of corrosion medium to the substrate and reduce the corrosion rate.