Pretreatment composition for phosphatising ferrous metals, and method of preparing the same.

摘要

An aqueous composition for the treatment of ferrous metal surfaces is a solution comprising: (a) titanium compound in amount from 1 to 100 parts per million by weight, measured as titanium; (b) phosphate and/or acid phosphate in amount totalling from 50 to 1500 parts per million by weight, measured as PO4; (c) pyrophosphate in amount from 10 to 300 parts per million by weight, measured as P2O7; and (d) carbonate and/or acid carbonate in amount totalling 20 to 1500 parts per million by weight, measured as CO3; the solution having a pH from 8.5 to 9.5.