Electrolytic preparation method for composite phosphating film

Abstract

The invention discloses an electrolytic preparation method for a composite phosphating film. A composite phosphating film treating fluid mainly consists of phosphoric acid, nitric acid, zinc oxide, nickel sulfate, sodium phytate, sodium hexafluorophosphate, succinic acid, ammonium phosphomolybdate, hydroxylamine sulphate, cerium nitrate, hydrogen peroxide and water, and can be used for cold machining and machine manufacturing. According to the preparation for the composite phosphating film disclosed by the invention, an inert material is taken as a working electrode, and a special current applying method is adopted to treat to form an organic phosphating-inorganic phosphating composite protective layer which is excellent in performance and is doped with rare-earth elements on the surface of a workpiece substrate. During operation and use, the electrolytic preparation method has the characteristics of a medium-low temperature, short treatment time and high film-forming efficiency; and atreated workpiece has excellent stretching ductility and excellent extruding property, and can be popularized to various precise forming pre-treatment processes.

Description

technical field

[0001] The invention relates to a metal surface treatment technology, in particular to an electrolytic preparation method of a composite phosphating film. technical background

[0002] The traditional chemical phosphating process has been widely used in the cold forming processing and manufacturing industries of steel and other metals. Due to the fact that most of the process requires heating at medium and high temperatures during production, and there are many phosphating residues, it is easy to adhere to the surface of the workpiece and cause damage during the cold forming process. The accuracy decreases and the loss of equipment increases, resulting in high production costs. Electrolytic phosphating technology is favored by cold forming processing because of its short phosphating time, low phosphating temperature, and less or even no phosphating slag. Generally, during electrolytic phosphating, oxygen is evolved on the surface of the anode (inert material...

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