Influence Of Adulterating Vanadium, Molybdenum And Yttrium On Resistive Corrosion Of Zn-Fe Alloy Coating

The direct electrodeposition was used to produce Zinc-iron alloy coating on the surface of A3 steel substrate, which indicates that the best technical parameters of electroplating through many experiments are the following: the temperature of electroplating solution is 30°C;the time of electroplating is 30 minutes; the pH of electroplating is 3.0±0.5; the current density is 20 mA/cm²; the best content of FeSO₄·7H₂O is 8g/L.The influence of vanadium salt,molybdenum salt and yttrium salt on the microstruc-ture and appearance of Zinc-iron alloy coating was studied by SEM and XRD,and the corrosion behavior of the Zinc-iron alloy coating was also studied by the galvanostatle method,electrochemical impendence chat and cyclic voltammetry in the sulfuric solution at 30°C on the condition of adulterating vanadium salt,molybdenum salt and yttrium salt.The results indicate that the crystallization cell size of Zinc-iron alloy coatings becomes small,uniform and close together.The Zinc-iron alloy coatings orientation texture coefficient has changed, and the i_pp and i_p of Zinc-iron alloy coating decrease obviously. Rp increases.The corrosion resistance of the Zinc-iron alloy deposit is strengthened markedly in 0.5mol/L H₂SO₄ solusion when some weights of vanadium salt have been added in electrolytes.The spread around capability of the electroplating solusion is improved,the crystallization cell size of Zinc-iron alloy coatings becomes small,uniform and close together.The Zinc-iron alloy coatings orientation texture coefficient has been changed, and the i_pp and i_p of Zinc-iron alloy coating decrease obviously. Rp increases.The corrosion resistance of the Zinc-iron alloy deposit is strengthened markedly in 0.2mol/L H2SO4 solusion when some weights of molybdenum salt added in electrolytes. When some weights of yttrium salt have been added in electrolytes, the surface tensility of the electroplating solusion decrease.The crystallization cell size of Zinc-iron alloy coatings becomes small because yttrium offers the heterogeneity crystalloid for the crystallizing of Zinc-iron alloy coating.The Zinc-iron alloy coatings orientation texture coefficient decreases partially, and the i_pp and i_p of Zinc-iron alloy coating decrease obviously.Rp increases.The corrosion resistance of the Zinc-iron alloy deposit is strengthened markedly in 0.2mol/L H₂SO₄ solusion.