Aqueous acid bath for zinc plating process and zinc plating process using the bath

摘要

An acid and aqueous bath for a galvanizing process comprises potassium chloride, zinc chloride, boric acid, an anionic or nonionic surfactant, methanol, acetic acid, metallic iron and copper. An acid and aqueous bath for a galvanizing process contains: (a) potassium chloride at a concentration of 275-300 g/l; (b) zinc chloride at a concentration of 120-135 g/l; (c) boric acid at a concentration of 45-50 g/l; (d) an anionic or nonionic surfactant at a concentration of 185-205 cm3/l; (e) methyl alcohol at a concentration of 5-6.5 cm3/l; (f) acetic acid at a concentration of 6.5-7.5 cm3/l; (g) metallic iron at a concentration of 135-150 ppm; and (h) copper at a concentration of 17-19 ppm. An Independent claim is also included for a galvanizing process using an aqueous acid bath as above and is put into service at a temperature of 25-28 degrees C, a pH of 4-5.5, a current density of 15.2-16.8 A/dm2, a chassis voltage of 2.35-2.85 volts and with a rotary barrel of hexagonal section at a voltage of 9.45-11.55 volts, allowing the application of a zinc coating at a speed of 17-23 microns/hour.