Patent ID: 6168674
Filing Date: 2001-01-02
Classification: C23C

Abstract:
A process of phosphatizing metal surfaces comprising contacting a metal surface comprising iron or steel with an aqueous acid phosphatizing solution comprising: 0.4 to 2.0 g/l Zn 7 to 25 g/l P.sub.2 O.sub.5 0.005 to 0.5 g/l peroxide wherein the peroxide is calculated as H.sub.2 O.sub.2 0.01 to 10 g/l formate wherein the formate is calculated as format ion, said phosphatizing solution being free from chlorate and added nitrite, the weight ratio of free P.sub.2 O.sub.5 to total P.sub.2 O.sub.5 is from 0.03 to 0.20, and the free acid points have been adjusted to a value in the range from 0.5 to 2.5; and rerinsing the phosphatized metal surfaces with water which has been adjusted with mineral acid to a pH of from 3.6 to 5.0.