Cyanide-free copper plating solution assistant and copper plating solution

Abstract

The invention discloses a copper plating solution assistant composed of a complexing agent and an additive. By combining the copper plating solution assistant with a main salt and a strong acid to form a unique cyanide-free copper plating solution, the cyanide-free copper plating solution can dissolve a compact passivation coating on the surface of stainless steel, so that the surface is activatedquickly to expose stainless steel crystal structures, and therefore, more deposition points are provided to copper ions. Meanwhile, the copper ions are complexed by using the complexing agent, so that potentials of the copper ions are reduced to inhibit a copper-iron replacement reaction. The bivalent copper ions are reduced at a high speed on the surface of the stainless steel to a copper coating by means of reducibility in an acidic copper plating solution, and the compact crystal copper coating with a superstrong binding force rather than a non-replacement copper layer is formed quickly before the replacement reaction, so that the copper ions are electro-deposited on the copper coating to electroplate copper quickly. The technical problem that a copper-iron replacement reaction industry in a high acid condition is solved successfully. The copper coating is superstrong in binding force which reaches the GB5270-2005 national standard. Copper can be plated on a stainless steel substrate directly and quickly.

Description

technical field [0001] The invention relates to a cyanide-free copper plating liquid additive and a copper plating liquid, belonging to the technical field of electroplating. Background technique [0002] As a special steel, stainless steel is easy to form a thin, transparent and dense passivation film with strong adhesion on its surface, and this film has a strong self-recovery ability, even if it is damaged, it can still regenerate a new passivation film. membrane. It is precisely because of the existence of the passivation film that it is very difficult to electroplate copper on stainless steel materials. After using traditional electroplating solutions and electroplating processes, the bonding force between the coating and the stainless steel substrate is extremely poor, and the electroplating quality is very low. The same problem also exists on cast iron substrates and plain carbon steel substrates. [0003] Therefore, if you want to obtain high-quality stainless stee...

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Problems solved by technology

[0005] In addition, direct copper plating on the above-mentioned steel substrates, the common copper plating environment is alkaline, such as alkaline cyanide copper plating process, because cyanide is the best complexing agent in the metal electrodeposition process, but has been It cannot be used in an acidic environment, and cyanide has no activation ability on the surface of stainless steel, so a copper plating layer with good adhesion cannot be obtained

Moreover, the high toxicity of cyanide poses a serious threat to operators and is not friendly to the environment.

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