Cyanide-free alkaline copper electroplating solution and electroplating process

Abstract

The invention discloses a cyanide-free alkaline copper electroplating solution and an electroplating process thereof. The cyanide-free alkaline copper electroplating solution comprises 3-50 g / L of cuprous compound, 0-20 g / L of pH regulator, 10-150 g / L of cyanide-free main complexing agent and 1-30 g / L of brightening agent, wherein molecules of the cyanide-free main complexing agent at least comprise two double bonds, and atomic energy of the at least two double bonds participate in complexing of the same cuprous ion. The cyanide-free alkaline copper electroplating solution provided by the invention does not contain pollutants such as cyanides and phosphorus, wastewater treatment is simple, the environmental requirements are met, and the system of the cyanide-free alkaline copper electroplating solution contains cuprous ions. During electroplating, only one electron needs to be consumed for forming one copper atom, and energy consumption is small. Moreover, the atomic energy of the at least two double bonds of the molecules of the complexing agent can participate in complexing of the same copper ion, the complexing capability is high, and an obtained plating is good in brightness and smoothness and excellent in dispersing capacity.

Description

technical field [0001] The invention relates to the technical field of electroplating, in particular to a cyanide-free alkaline copper plating electroplating solution and an electroplating process. Background technique [0002] In the electroplating industry, cyanide copper plating is currently mainly used for the primer coating when electroplating materials such as steel, aluminum alloy, zinc and zinc alloy, and also for the electroplating of copper alloys. It has the advantages of good bonding force of the coating, simple process components, convenient maintenance, and no corrosion of the substrate by the plating solution. However, cyanide is a highly toxic substance. The lethal dose of oral sodium cyanide and potassium cyanide is 1 to 2 mg / kg. The water mist containing cyanide produced when the plating solution is heated during the production process is poisonous to the operator, and the electroplating wastewater It will also cause harm to the ecological environment. Ho...

AI Technical Summary

Problems solved by technology

In the above-mentioned complexing agent molecules of these monovalent cyanide-free copper plating solutions, there is only one atom on the double bond that can participate in the complexation of the same copper ion, so in the chelate formed by these complexing agents and monovalent copper ions, only A d-π* feedback π bond is formed, so that the electrons on the copper ion cannot be fully dispersed into the ligand, the electron cloud density is larger, the energy is higher, and the stability of the complex is not as good as that formed by two or more coordination atoms Complexes with double bonds, the complexing ability of the ligand is relatively limited, and the complexing constant is relatively small

According to the Nernst equation, it can be seen that the negative shift of the electrode potential is insufficient, the overpotential during the electroplating process is relatively insufficient, and the crystal nucleus generation rate is relatively slow, which in turn leads to relatively large crystal grains, which ultimately leads to relatively insufficient brightness and flatness of the coating, and relative dispersion ability. limited

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