Research Study On Performance Of Low Temperature Sintered Chemically Reactive Enamel Coating

Corrosion of steel bars is an important factor which affects the durability of concrete.Chemically reactive enamel(CRE)coating as an inorganic coating can effectively reduce corrosion of steel bars,but its high sintering temperature lower the mechanical properties of steel.As a result,a new type of low-temperature sintered chemically reactive enamel(LTE)coating have emerged,which changes the raw materials and process of CRE coating.The microstructure,corrosion resistance and adhesion properties of LTE coating are analyzed by various test methods.And the influence of different spray-sintering times on micro structure and corrosion resistance is also considered.The main test methods and conclusions of this paper are as follows:(1)The microstructure and material composistion of LTE coating were analyzed by scanning electron microscopy(SEM),energy dispersive spectrometer(EDS)and X-ray diffraction(XRD).It was found that,the coating thickness is increased,the pores are reduced,the structure is more compact with the increase of spraying times.There is no interface which caused by several spray-sintering times.formed in coating.The boundary layer between the coating and steel appears,which can increase the bonding performance,it is the evidence of chemical reaction of LTE coating and steel.(2)The corrosion resistance and mechanism of uncoated/LTE coated steel bar with different spraying times were investigated and compared by salt spray test and peeling test.It was found that corrosion resistance increased with the increase of spraying times,corrosion resistance of 3 spraying times LTE coating is much better than 1 or 2 spraying times coating.Corrosion products just appears in corrosion pit because of the self-healing ability of LTE coating.(3)The corrosion resistance and mechanism of uncoated/LTE coated steel bar with different spraying times were quantitatively analyzed by open circuit potential(OCP),electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization.From these three electrochemical test,the corrosion resistance of LTE coated steel is 30 times larger than uncoated steel,and multiple spraying times can significantly improve the corrosion resistance of LTE coated steel.(4)The bonding performance between LTE coated steel and concrete were tested by pull-out test.The results show that,bonding performance of LTE coated steel is 1.77 times larger than uncoated steel because of reaction between coating and concrete in cement hardening process.