Zinc Nickel Codeposition in Ammonium Sulfate Combined Effect of Cadmium And Boric Acid

摘要

Zinc-nickel electrodeposited alloys are of great interest since these alloys show higher corrosion protection, better mechanical properties and thermal stability compared to bare zinc and other zinc alloys coatings. Zinc-nickel alloys were obtained from ammonium sulfate baths in the presence of boric acid and boric acid-cadmium. It has been shown that anomalous codeposition can be minimized by using both boric acid and cadmium. Boric acid decreases current density which minimizes anomalous deposition, in the other hand cadmium decreases strongly zinc deposition. The combination of boric acid and cadmium increases the percentage of nickel in the deposit. In a way the combination of boric acid and cadmium allows to obtain a ternary coating Zn-Ni-Cd which has higher nickel content compared to that in Zn-Ni obtained from ordinary Zn-Ni baths .