Preparation and Evaluation of Phosphating Solution for Room Temperature Applications

摘要

The preparation of Zn-Mn-Ni phosphating solution (for room temperature applications) which uses nitric acid- sodium nitrate-sodium fluoride as the accelerant was described in this article. The film weight and corrosion resistance properties were investigated. The influences of fluorine, nickel and the manganese on the phosphating process were investigated and the corrosion resistances of the phosphating film were evaluated. The new system overcomes some disadvantages of phosphating at medium or high temperature such as high energy-consumption, high cost and low efficiency. Using the proposed solution and process, the phosphation is stable in film formation. The resultant film is uniform in thickness, little sediment and excellent corrosion resistance.