The Study On Graphene-based Anti-corrosion Coating For Steel

With the rapid development of China's economy and the implementation of the "one belt and one way" strategy,large-scale infrastructure has been in the process of brewing,construction and operation.Ensuring the safety of the engineering structure will become an important topic affecting the healthy and rapid development of the national economy.Steel structure and reinforced concrete structure are important structural forms in the field of civil engineering,which account for a large proportion.Corrosion is one of the main causes of durability damage of structural materials.At the same time,it causes huge economic losses and casualties.Therefore,it is particularly urgent to study corrosion-resistant steel anticorrosive coatings.Graphene is a new two-dimensional planar material developed in recent years.It has strong penetration and barrier ability,and can isolate oxygen,water molecules and smaller potential corrosion media.Based on this,the graphene-based anti-corrosion coatings for steel sheets and rebars which are prone to corrosion are studied.The graphene-based anti-corrosion coatings system is established to solve the problem of interface bonding.On this basis,a new graphene-based process coatings are obtained.Composite corrosion resistant coatings were prepared on steel surface using underwater cured epoxy resin,silane coupling agent,water-borne graphene and oil-borne graphene as materials.By means of polarization curve,scanning electron microscopy,salt spray test and scratch test,the corrosion rate,micro-morphology,salt spray resistance and bonding strength with steel surface were measured.It was found that the composite coating resisted salt spray corrosion for more than 10 hours,the coverage of carbon elements on the coating surface was over 90%,and the evaluation grade of coating scratch was 5B.It is found that the corrosion resistance of the coating can be increased by increasing the overall thickness of the composite coating.In addition,the corrosion resistance of the coating can be further increased by coating the steel plate treated with NaOH or KOH and other strong alkaline solutions on the surface.Silane coupling agent and water-borne graphene were used as raw materials to prepare silane coupling agent-water-borne graphene composite corrosion resistant coatings on steel bars.It is proved that in the corrosive medium containing chloride ions,the surface coating of the reinforced concrete members coated with the composite coating is not damaged.At the same time,through the central pull-out test of the reinforced concrete members,it is found that the influence of the composite coating on the bond performance between the reinforcement bars is relatively small,and the bond strength of the reinforced concrete members coated with the composite coating is reduced by less than 10%.