Stainless steel surface large area brush Pd-electroplating process

Abstract

Disclosed is a large area electric brush palladium plating technique on the surface of stainless steel, which belongs to special electroplating field. The shortcomings of electroless palladium plating are that the electroless palladium plating is unsuitable to plate in large area and unsuitable to construct and repair in the spot. The technique of the invention comprises surface preliminary treatment and electric brush plating steps, which is characterized in that plating solution comprises palladium salt Pd (NH3)4C12. The measure of the plating solution is measured by quality of Pd: 5-12g / L, NH4C1: 50-125G / l, (NH4)2PO4: 50-100g / L, polyoxyethylene sorbitol anhydride single laurate: 0-0.002ml / L, NH3,H2O: 10ml-80ml / L, the left is water, and the pH measure of the water is 7-8. Processing parameter is as follows: voltage: 5V-10V, plating pen is utilized as anode, work piece is utilized as cathode, the speed which the plating pen relates to the work piece is 8-12cm / s, and the temperature is normal temperature. The invention has the advantages of large area plating in the spot, fast speed of plating, simple operation, low cost respectively, and good environmental protection performance, and furthermore the invention can immensely improve anti-corrosion capability of the stainless steel after being plated.

Description

technical field [0001] The invention belongs to the stainless steel surface anticorrosion treatment process working in the harsh environment of high-temperature non-oxidizing medium (especially acidic medium). The brush plating technology used in the treatment process used in the invention belongs to special electroplating technology, which can implement on-site plating of equipment and fixes. Background technique [0002] Stainless steel itself has the advantages of strong corrosion resistance and beautiful surface. The surface can form a dense passivation film in oxidizing medium to prevent the infiltration of corrosive medium, so as to achieve the purpose of protecting the substrate. However, in many chemical plants in my country, some stainless steel equipment is used in the harsh environment of high-temperature non-oxidizing media (especially acidic media), and a dense passivation film cannot be formed on the surface of stainless steel, resulting in serious corrosion pr...

AI Technical Summary

Problems solved by technology

However, in many chemical plants in my country, some stainless steel equipment is used in the harsh environment of high-temperature non-oxidizing media (especially acidic media), and a dense passivation film cannot be formed on the surface of the stainless steel, resulting in serious corrosion of the equipment.

There are few protection methods available under such conditions. One method is anodic protection technology, but the operation of this technology is complicated and the applicable occasions have great limitations.

Another method is to choose stainless steel or titanium alloy with a higher corrosion resistance level, but this method involves equipment renewal, which requires huge investment and cannot protect the original equipment

[0003] The electroless palladium plating and electroplating palladium processes reported in the current literature and patents are relatively complicated. The electroless palladium plating is to deposit palladium on the surface to be plated through the self-catalytic reduction of the reducing agent. The electroless palladium plating must go through cumbersome pretreatment steps. It takes a long time for plating, and the materials are mostly limited to ceramics, glass, and porous stainless steel surfaces. The reducing agent is mostly toxic hydrazine or hydrazine derivatives, and it is rare to plate on general stainless steel surfaces.

Electroplating palladium is to deposit palladium on the surface to be plated through the reduction of electric current. The brush palladium plating process reported in the current literature and patents not only has a small plating area at one time, but also has a large ammonia concentration, and the construction environment is not good. The field is mainly limited to the surface plating of copper or copper-silver alloy commutator to maintain a small contact resistance, and there is no report on the corrosion protection of stainless steel in high-temperature non-oxidizing media, such as the Chinese patent "Used for micro-motor commutator Brush Plating Process and Materials", application number: 99116933.6, the composition of the brush plating solution is a certain concentration of PdCl 2 、NaNO 3 and NH 4 NO 3 , brush-plating on the commutator of ultra-micro motors with a plating pen to obtain a better quality coating, which can maintain low contact resistance and stabilize the performance of ultra-micro motors

The patent of electroless palladium plating on stainless steel in high temperature non-oxidizing medium is under review. The application number is: 200610113505.4. It is easy to operate, low in cost and high in efficiency. The protective performance in non-oxidizing medium (especially acidic medium), its advantage is that it is convenient to process small and medium-sized parts with complex shapes, and its disadvantage is that it is not suitable for large-area (more than 1 square meter) plating, and it is not suitable for on-site construction and repair

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