Electrochemical tests on zincating solution with zinc sulfate and zinc oxide
(1.黑龙江省哈尔滨市哈尔滨工业大学应用化学系2.Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001, China)
Abstract: In order to find out a multi-metal zincate solution to get good micromorphology and fine adhesion of coatings, sulfate zincate and zinc oxide zincate with different chelating agents combinations, of which there are 8 solutions are designed. CHI630 electrochemical test system is applied to measure the φ—t curves of zincate process and Tafle curves of zincated plates in 3.5% NaCl medium. The analyzed results show that when molar ratio of sodium hydroxide to zinc ions is constant, the better chelating agents combination for multi-metal zincation solution is the combination of sodium potassium tartrate and sodium citrate in zinc oxide solution, from which zinc alloy is high in potential and perfect in corrosion resistance. After the second zincate immersion for 60s, the immersion potential is -1.606V(vs SCE). The corrosion current density is 6.612, J_ corr/(A·cm-2); and the corrosion potential is -1.381, φcorr(I=0)/V.
Key words: high silicon aluminum alloy； multi-metal zincating solution； dipping time； dipping active potential； Tafle curve