Method for preparing chromate-free passivation film capable of improving oxidative resistance of chemical plating Ni-P layer

Abstract

The invention discloses a method for preparing a chromate-free passivation film capable of improving oxidative resistance of a chemical plating Ni-P layer. The method comprises the following steps: S1, under normal temperature, dissolving salt containing VO3<-> in deionized water, and adjusting the molar concentration and pH of the VO3<-> solution to 0.01-0.1 mol / L and 1.0-1.5 to prepare passivation solution; S2, adopting deionized water to wash the chemical plating Ni-P layer prepared on the surface of a part; S3, under normal temperature, dipping the part in the S2 in the passivation solution prepared in the S1, and standing for 10-120 minutes; and S4, taking the part out of the passivation solution, washing the part with deionized water, and preparing the chromate-free passivation filmwith high oxidative resistance on the chemical plating Ni-P layer on the surface of the part. The method is suitable for popularization and application in improvement operation of the oxidative resistance of the chemical plating Ni-P layer in a large-scale and commercialized manner and is broad in market prospect.

Description

technical field [0001] The invention relates to surface treatment technology, in particular to a method for preparing a chromium-free passivation film for improving the oxidation resistance of an electroless Ni-P layer. Background technique [0002] In surface treatment technology, electroless plating technology has the characteristics of simple equipment and low energy consumption compared with electroplating technology, and can form a coating with uniform thickness on the surface of complex substrates. Therefore, electroless plating technology is widely used in surface treatment of parts in various fields in technology. [0003] Among all chemical plating layers including Au plating layer, Ag plating layer, Cu plating layer, Sn plating layer, Ni-B plating layer and Ni-P plating layer, the chemical plating Ni-P layer not only has Good corrosion resistance, and it can also adjust the ratio of Ni element to P element or perform pre / post treatment, so that the hardness, wear ...

AI Technical Summary

Problems solved by technology

In the prior art, the chemical passivation of the electroless Ni-P layer is mainly a chromium salt passivation process and a cadmium-free passivation process; wherein, the chromium salt passivation process has serious environmental pollution problems and has been almost eliminated; none Cadmium passivation process is divided into molybdenum salt passivation process, manganese salt passivation process, manganese / silicon compound salt passivation process, tungstate passivation process and vanadium salt passivation process, molybdenum salt passivation process, manganese salt passivation process, etc. The salt passivation process, the manganese / silicon compound salt passivation process and the tungstate passivation process all have the technical problems of relatively high implementation temperature and high energy consumption, while the vanadium salt passivation process can be carried out at room temperature with low energy consumption. (For example, "an alkaline chromium-free passivation solution and its method for passivating the electroless Ni-P layer at room temperature" disclosed in Chinese patent literature, publication number CN105525282, publication date April 27, 2016)

However, the vanadium salt passivation solution of the existing vanadium salt passivation process contains organic reagents such as triethanolamine, citrate and acetate, which will increase the technical difficulty and cost of the environmental protection treatment of the vanadium salt passivation waste solution , It is not conducive to the popularization and application of vanadium salt passivation process in the large-scale, commercial electroless Ni-P layer oxidation resistance improvement operation, which directly affects the vanadium salt passivation process in the electroless Ni-P layer oxidation resistance improvement operation process of industrialization

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