| Metal corrosion causes a lot of economic losses and waste of resources,and even endangers people’s lives.With the development of industrialization,the accumulation of solid waste fly ash has become increasingly serious.In order to improve the utilization rate of fly ash and reduce the negative impact of metal corrosion on society,fly ash was used as a coating filler in coatings in this study.Fly ash can fill up defects such as polymer chain gaps in the coating.However,untreated fly ash is difficult to provide longer-lasting anti-corrosion properties for coatings,so it is often functionalized.In this paper,three kinds of anti-corrosion functional coatings based on fly ash are designed.（1）Fly ash,graphene oxide and multi-wall carbon nanotubes are stacked on each other,and a three-dimensional network filler imitating concrete is designed,which effectively improves the corrosion resistance and wear resistance of water-based epoxy coatings.After the filler is chemically modified,a large number of epoxy groups or amino groups are grafted on the surface of the filler,and the modified group promotes the multi-dimensional crosslinking reaction of filler-filler,resin-filler,and resin-resin inside the coating.By virtue of the stable characteristics of the"imitation"concrete structure and the excellent interfacial bonding strength of the silane-modified composites,the composite coating exhibits excellent anti-corrosion and wear-resistant properties.In the electrochemical impedance spectroscopy test,the low-frequency impedance value of the target coating is stable at about 1×107Ω·cm2.The results show that the three-dimensional network filler has a good degree of bonding with the coating matrix,and the interfacial chemistry of the filler surface improves the compatibility of the functional filler with the waterborne epoxy resin.Using industrial waste fly ash as the main filler of the coating is conducive to promoting the recycling of resources.（2）A dual-function filler platform with both shielding performance and corrosion inhibition activity is designed.Fe2+/Fe3+and perfluorinated groups act as strengthening factors for this platform,endowing the coating with excellent barrier properties and strong corrosion inhibition activity.In addition,the perfluorinated groups enhance the hydrophobic properties of functional fillers and provide effective complexation inhibition for the anodic reaction region.Fe2+/Fe3+enables functional fillers to exhibit anodic protection and cathodic inhibition properties at the interface between the coating and the substrate,and promote the formation of a corrosion passivation film with a wider coverage on the metal substrate.In the electrochemical impedance spectroscopy test,after the FPF-Fe10%C sample was soaked in12%sodium chloride solution for 30 days,its|Z|0.01 Hzvalue still reached 7.91×108Ω·cm2.Moreover,the FPF-Fe10%C sample showed a lower cathodic corrosion tendency in the scanning vibrating electrode test,which indicated that Fe2+/Fe3+effectively suppressed the corrosion reaction in the cathodic region.（3）A silanized fly ash-based strong cross-linked polyurea anti-corrosion coating is designed.Fly ash filler has the shielding properties of inert fillers,but its particle size is not uniform,its shape is irregular,and its surface has no obvious organic functional groups,so it is difficult to build a better corrosion shielding layer.In this chapter,the method of acid leaching is used to optimize the composition of fly ash,increase the content of silicon-alumina oxide in fly ash,and make it show better shielding effect of filler.On this basis,it was modified with hydrophilic and hydrophobic functions,and the interfacial binding ability of different functionalized fly ash and coating matrix was studied.The results show that the hydrophilic modified fly ash is beneficial to improve the bonding force between the filler and the resin,and the unique polymerization mechanism of the silanized modified fly ash filler and the polyurea matrix is further discussed. |
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