| 摘要 |
Metal surfaces, particularly zinc and zinc alloy surfaces, are treated with an aqueous acidic solution containing effective amounts of A) hydrogen ions to provide a pH of about 1.5 to about 2.2, B) an oxidizing agent, C) at least one of iron, cobalt, nickel, molybdenum, manganese, aluminium, lanthanum, lanthanide mixtures or cerium ions or mixtures thereof, or instead of C) iron and cobalt ions. Other treating solutions also incorporate D) chromium ions substantially all of which are in the trivalent state, and iron ions in combination with an additional metal from C) or cerium ions, or A), B), C) and D) and F), a bath soluble and compatible silicate compound or A), B), C) and D) and G), a mixture of 1-hydroxyethylidene-1,1 diphosphonic acid and citric acid or mixtures of A), B), C) and D) with two or more of E), F) and G). The treating solution may optionally further contain halide ions and a wetting agent. ) |
