THE TEXTURES OF ZINC ELECTRODEPOSITS ON STEEL AND THEIR EFFECT ON THE CORROSION RESISTANCE

In this work, textures of Zn deposits on mild steel are correlated with the corrosion resistance of the base metal. Textures of electrodeposits chemically obtained were studied by using X-ray diffraction. Zinc deposits were made simulating industrial conditions of temperature, time and current density, using electrodeposition solutions of ZnCl2 + NH4Cl (in the presence/absence of thiourea). According to reports, Zn deposits with a basal planes high intensity (0,0,2) and low intensities in pyramidal planes ((1,0,3), (1,1,2), (2,0,1)), more resistant to corrosion. For low electrodeposition times, zinc deposits developed a (1,0,3) texture, showing in this case high corrosion current densities. On the contrary, for higher deposition times (10 minutes), deposits developed a (0,0,2) texture and the value of the corrosion current decreases markedly. The prevalence of texture (0,0,2) in the basal planes and low XRD intensity for (0,0,3) texture in the pyramidal planes are associated to deposits having high corrosion resistance.