| The hydraulic machinery suffers form severe erosion and corrosion damage in the course of service,which will result in a large number of destroying and failure for mechanical parts.It also makes a lot of economic losses.Therefore,the requirements of the anti-corrosion and erosion wear performance of hydraulic mechanical components are getting higher and higher.So it is very important to develop the coating with high erosion resistance and corrosion resistance,which is important to protect the consumable parts,reduce energy consumption,save material,reduce the occurrence of safety accidents in industrial production and improve industrial production efficiency.Based on the shortcomings in the study of anti-corrosion wear coating,a epoxy terminated polyurethane elastomer(ETPU)was synthesized firstly in this paper as the toughening agent,and the effect of ETPU toughening agent on the mechanical properties and erosion resistance of epoxy coating was studied.On this basis,further studying the effects of SiC surface modification and its content on the erosion resistance and corrosion resistance of EP / ETPU composite coatings;Finally the effects of modified glass fiber content on the erosion resistance and mechanical performance of EP / ETPU/modified SiC composite coatings were investigated.The main contents and results are as follows:(1)A epoxy terminated polyurethane elastomer(ETPU)was synthesized and the effect of ETPU on the mechanical properties and erosion resistance of epoxy coating was studied.It was found that the polyurethane could improve the bonding strength of EP / ETPU blends and the notched impact properties of the blends increased with the increase of ETPU content.Besides the results also show that the toughening effect of ETPU2000 is better than that of ETPU1000.In addition the DSC curve of pure EP curing in the normal temperature shows a typical exothermic peak,which exhibit that the cure reaction is not completely,but when the pure EP curing in the heating environment,the typical exothermic peak disappeared,so the coatings are cured completely.With the increase of ETPU2000 content,the glass transition temperature of composite materials moves to low temperature,and it is lower than the glass transition temperature of pure EP which cured in heating environment.ETPU2000 can significantly improve the erosion resistance performance of EP coating and the erosion weight loss achieve the minimum in the ETPU2000 content of 15%.(2)The effects of surface modification of SiC particles and the modified SiC contents on the mechanical and erosion resistance of EP / ETPU composite coating was investigated.on the mechanical properties and erosion resistance of EP / ETPU composites were investigated.Finally find that,the bonding strength of the composites was decreased after adding SiC to EP/ ETPU system.At the same time,the impact strength of EP / ETPU / modified SiC composite coating decreases with the increase of modified SiC;With the increase of modifiedSiC content,the hardness increases first and then decreases and reaching a maximum of13.5HB when the modified Si C content is 60%;The modified SiC particles can significantly improve the erosion resistance of EP / ETPU coating,and the erosion loss weight is minimized when the modified SiC content is 60%.(3)On the basis of(2)the effects of curing process,surface modification and the addition of modified SiC on the corrosion resistance of epoxy composite coatings were investigated.The impedance spectra and polarization curves of EP / ETPU / modified SiC composite coatings were tested by electrochemical method.The results show that the corrosion resistance of the composite coating is better when the coating is cured in heating environment,and the normal curing system is weak to protect the metal.The coating / metal interface is easy to peel and the acidic medium is easy to enter the metal surface.After the surface modification of SiC,the lipophilic silicone structure was introduced,and the epoxy groups on the surface can react with the curing agent,so that the shielding effect of the coating on the acid corrosion medium was enhanced.When the modified SiC content is 60%.(4)The effects of modified GF on the erosion and wear properties of EP / ETPU /modified SiC composite coatings were investigated.It was found that the bonding strength and impact strength of the composite coatings showed a slight increase with the increase of the modified GF content.Erosion wear performance and erosion wear surface SEM test showed that with the increase of modified GF,the wear weight loss of the composite coating decreases first and then increases.When the amount of modified GF is up to 8%,it can disperse the best in the composite coating,and can effectively absorb the erosion energy,prevent the crack propagation and reduce the fatigue fracture.Finally,the anti-corrosion epoxy composite coating which contains 15% ETPU2000,60% modified SiC and 8%modified GF in epoxy matrix was prepared. |
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