The passivation of zinc alloy coating was achieved through the utilization both silicate and trivalent chromium systems, employing a specific process formula consisting Co(NO3)2 at concentration 2.5 g/L, C76H52O46 3 mL/L, Na2SiO3 25 C6H5Na3O7 15 an appropriate amount organic accelerator. composite tannic acid found to be more effective than film, as it successfully eliminated dendrite structure...