Electronickelling chromate-free passivator and preparation method thereof

Abstract

The invention provides an electronickelling chromate-free passivator and a preparation method thereof. The electronickelling chromate-free passivator comprises the following components of, by weight,12-20 parts of acetic acid, 2-8 parts of sodium citrate, 3-10 parts of cobalt nitrate, 6-15 parts of sodium phosphate, 4-12 parts of phosphoric acid, 1-6 parts of potassium ferricyanide, 4-9 parts ofsodium molybdate, 5-15 parts of water soluble persulfate and 300-1000 parts of water. The electronickelling chromate-free passivator provided by the invention is simple and environmentally friendly incomponent, hexavalent chromium and other toxic substances are not contained, volatile gas and smell are avoided during passivation, environmental friendliness is achieved, passivation speed is high,passivation time is only 5-10 s, a passivated electronickelling product has good corrosion resistance and inoxidizability, and the surface is smooth and glossy.

Description

technical field [0001] The invention relates to the technical field of chromium-free passivating agents, in particular to a chromium-free passivating agent for electroplating nickel and a preparation method thereof. Background technique [0002] Because electroless nickel plating and electroplating nickel have excellent comprehensive properties such as hardness, wear resistance, corrosion resistance, electrical conductivity and special magnetic properties, they are widely used in important industries such as automobiles, petroleum, aerospace, mechanical equipment, computers and electronic communications. field. However, in the atmospheric or corrosive environment, nickel oxides or sulfides are easily formed on the surface of nickel plating. This layer of oxides will cause the surface of the coating to lose its metallic luster, turn yellow and darken, or appear spots, which seriously affect the appearance of the coating. For the PCB field, this layer of oxide not only increa...

AI Technical Summary

Problems solved by technology

However, the passivation effect of hexavalent chromium-type passivators varies greatly with the content of hexavalent chromium, and the passivation effect is not stable at the same time, and the corrosion resistance is poor, which cannot effectively protect the surface of the nickel layer.

At the same time, because hexavalent chromium compounds are easily absorbed by the human body, they can invade the human body through the digestive system, respiratory tract, skin and mucous membranes, so they are more harmful to the environment and human body