Preparation method of HEDP copper-plated non-porous thin layer

Abstract

The invention belongs to the technical field of cyanide-free copper plating technology, and particularly relates to a preparation method of an HEDP copper-plated non-porous thin layer. The preparation method comprises the steps that abrasive paper is used for polishing to remove floating rust at first, then, chemical degreasing and activation are carried out, and finally deionized water is used for cleaning; a plating solution is prepared; plating is carried out, particularly, an electrolysis copper plate is used as an anode, an oxidation film on the surface of the copper plate is removed, activation treatment is carried out for 5-10 s through a 10%-20% dilute hydrochloric acid solution, a base plate which is treated is used as a cathode to be placed in the plating solution, the temperature is 50-65 DEG C, the pH value is 9-11, direct current plating is carried out, the current density is 0.5-3.5 A/dm<2>, plating is carried out under the cathode moving condition, the moving speed is 3 cm/s-5 cm/s, and the HEDP copper-plated non-porous thin layer is obtained. The HEDP alkaline plating solution is low in toxicity, environmentally friendly and quite low in corrosion to production equipment, the leveling ability, dispersing ability and deep plating ability of the HEDP alkaline plating solution can reach or even exceed those of a cyanide copper plating solution, the cathode current efficiency reaches up to 95% or above, and the plating solution is stable in performance.

Description

technical field [0001] The invention belongs to the technical field of cyanide-free electroplating copper plating technology, and in particular relates to a preparation method of HEDP copper-plating non-porous thin layer. Background technique [0002] Cyanide copper plating has become the most widely used and mature pre-plating copper technology due to its good dispersion ability of plating solution, fine crystallization, and good bonding force between coating and substrate. However, it uses toxic and harmful cyanide and HCN produced by cyanide carbonation. It is also highly toxic, has strict requirements on the safety of the operating system, and costs a lot to deal with the three wastes. The development of an environmentally friendly cyanide-free copper plating process to replace the cyanide copper plating process is the focus of research in the field of electroplating industry. [0003] Although there are many types of cyanide-free copper plating processes, such as sulfa...

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Problems solved by technology

[0003] Although there are many types of cyanide-free copper plating processes, such as sulfate copper plating, ethylenediamine copper plating, pyrophosphate copper plating, etc.; but the actual application of each plating solution system is insufficient: for example, sulfate copper plating cannot be directly applied to steel substrates. Plating on top; nickel plating after copper plating with ethylenediamine, poor binding force; pyrophosphate in pyrophosphate copper plating will be partially hydrolyzed into orthophosphate, and the accumulation of orthophosphate will cause cracking of the performance of the plating solution; in addition, In the above copper plating process, the plating layer needs to be at least 18 μm to ensure a low porosity; due to these limitations, the current cyanide-free copper plating process has not substantially replaced the cyanide copper plating process

[0005] Copper coating is a kind of cathodic protective coating, which is usually used as the bottom layer of gold, silver, nickel and other coatings. For steel-based parts, if the HEDP copper-plated non-porous thin layer has more pores, a large number of small anodes and large cathodes will be formed. Corrosion Primary batteries, in a corrosive environment, cannot protect the steel substrate to slow down corrosion, but accelerate the corrosion of steel; at present, the thickness of the non-porous thin layer of HEDP copper plating in the carburizing and nitriding process of steel-based parts is usually 30 μm~ 60μm, or even thicker, and after the coating is thickened, large and numerous copper nodules are formed on the surface. This kind of HEDP copper-plated non-porous thin layer with poor density and poor surface state is not only difficult to play a good anti-seepage Carbon, anti-nitriding effect, and to a large extent cause waste of resources and energy loss; low porosity and good compactness of copper coating are the key to prevent the diffusion and penetration of carbon and nitrogen

In order to prepare a dense, high-quality HEDP copper-plated non-porous thin layer, some scholars use pulse current electroplating after pre-impregnation of copper, and alternately conduct DC and AC electroplating on the substrate to obtain HEDP plating with a thickness of about 20 μm and low porosity. Copper non-porous thin layer, but the deposition speed is slow, the operation process is complicated, and the equipment requirements are high, so it is difficult to popularize and apply

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