| This paper adopts the method of the preparation of Electrode posited Zn-Fe alloy coating on the substrate of Q235, studied the effect of surface morphology of electrode position process parameters on Zn-Fe alloy coating, on the deposition parameters were optimized by orthogonal test method, the conclusion that Zn-Fe alloy coating properties of ideal. Using SEM, EDS and XRD methods for the analysis of Zn coating, Zn-Fe alloy plating and Zn-Fe-SiC composite coating surface morphology, surface composition and the phase composition of the coating, corrosion resistance and electrochemical analysis method by neutral salt spray test comparison of coating, and the corrosion resistance of epoxy coating coated respectively after the comparison in the Zn-Fe alloy plating and Zn-Fe-SiC composite coating. The results are as follows:The process parameters were optimized by orthogonal test method, obtains the influence of process parameters on Zn-Fe alloy coating appearance size is as follows: the cathodic current density, temperature PH value. Preparation of Zn-Fe coating process parameters for the performance of the ideal: the cathodic current density 2A/ dm2, bath temperature of 30 DEG C, PH value is 4.5.Using S3400 scanning electron microscope electron microscopic structures were observed Zn coating, Zn-Fe alloy plating and Zn-Fe-SiC composite coating: observing the microstructure of the coating under scanning electron microscope, at the same magnification,crystalline Zn-Fe alloy coating is obviously higher than the crystallization of pure Zn coatings with fine, surface is smoother, more uniform grain distribution. Zn-Fe-SiC composite coating with SiC elements and SiC nanoparticle clusters, therefore, Zn-Fe-SiC composite coating has better corrosion resistance.Observed the texture coefficient of Zn coating and Zn-Fe alloy coating by means of Xray diffraction, Zn-Fe alloy coating crystal growth surface is mainly(002) crystal plane,(002)crystal surface texture coefficient of 60%. While the pure Zn coating crystal growth is the main surface(100),(101) and(102) crystal surface, texture coefficient were 89%, 4% and 7%.(002) surfaces for low index surfaces, the atomic binding ability is strong, and not susceptible to corrosion. Zn-Fe-SiC composite coating crystal growth surface is mainly(110) crystal plane,(110) surfaces for non close packed plane, Zn-Fe-SiC composite coating is more compact. Visible, adding SiC nanoparticles changed the preferred orientation of crystals,increases the corrosion resistance of the coating.The matrix of Q235 steel, Q235+Zn-Fe alloy coating samples and Q235+Zn-Fe alloy plating layer + epoxy coating specimens in 5%NaCl solution after soaking for 504 h, the weight loss is respectively 0.0866 g, 0.0512 g and 0.0229 g, the corrosion rate respectively is0.0680mm/a, 0.0400mm/a of the 0.0180mm/a. Coating epoxy coating at least makes theanti-corrosion performance of Zn-Fe alloy alloy coating is increased about 2 times, Prolong the service life of Q235 substrate. And coated with epoxy coating on Zn-Fe-SiC composite coating on the corrosion resistance, was significantly higher than that of Zn-Fe alloy coating. |
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