Phosphating soln. contg. boron fluoride - for phosphating ferrous and non-ferrous surfaces, e.g. steel, zinc and aluminium

摘要

Ferrous and non-ferrous metal surface are provided with a phosphate coating by treating the surface with a soln. contg. B fluoride in addn. to Zn- and Mn phosphate and oxidation agent. The soln., which contains Mn 5-50 wt.%, is used at 43 degrees C. Pref. the soln. contains 2-8 g/l Zn, 0.1-1.8 g/l Mn, 5-22 g/l PO4, 0.3-4 g/l BF4, pref. 1-9 g/l NO3, 0-8 g/l tartaric acid or tartrate, 0-0.5 g/l Ni and 0-0.75 g/l nitrite and/or chlorate. The use of B fluoride improves the quality of the phosphate coating and the soln. which does not requires a high temp., will give a phosphate coating on steel and non-ferrous metals such as Zn, and Al and Al alloys.