Pre-penetrant composition, pre-penetrant, copper plating pretreatment method and cyanide-free copper plating method

Abstract

The invention relates to a pre-permeation agent composition, a pre-penetration agent, a copper plating pretreatment method and a cyanide-free copper plating method. The pre-permeation agent composition comprises a first complexing agent, a second complexing agent and a third complexing agent, wherein the first complexing agent is succinate, the second complexing agent is selected from at least oneof tartrate and gluconate, and the second complexing agent is selected from at least one of ethidene diamine and glycerin; and the weight volume ratio of the first complexing agent to the second complexing agent to the third complexing agent is (15-30) g:(10-35) g:(1-4.5) mL. The pre-permeation agent composition is adopted for soaking pretreatment, the complexing agents penetrate into pores and cracks in the surface of a workpiece, and therefore copper ions can be well complexed in the subsequent cyanide-free copper plating process, defects such as invisible wee bubbles, cracks and pinholes in the surface of a workpiece to be plated are covered with a copper plating layer, the problem of bubbling caused by the pores in the surface of the workpiece can be solved, and the bonding force between the cyanide-free copper plating layer and an alloy substrate is improved.

Description

technical field [0001] The invention relates to the technical field of electroplating, in particular to a pre-penetrating agent composition, a pre-penetrating agent, a copper plating pretreatment method and a cyanide-free copper plating method. Background technique [0002] Zinc alloy has good casting performance and is an excellent casting alloy, which is more advantageous when casting workpieces with complex shapes and high precision. In the traditional zinc alloy electroplating process, cyanide copper plating is used as a pre-copper plating process. From a technical point of view, it has the advantages of good bonding force, good dispersion ability, fine crystallization, low porosity, stable plating solution and simple maintenance. However, cyanide is a highly toxic chemical, and its lethal dose to humans is only 0.005g, and the cyanide copper plating solution will release highly toxic cyanide during the electroplating process, which is harmful to the health of electropla...

AI Technical Summary

Problems solved by technology

However, the cyanide-free alkaline copper plating process of the above system generally has problems such as low deposition rate and poor bonding force. It cannot completely solve the problem of coating foaming after baking in the electroplating of zinc alloy die castings, and it has not been universally replaced. Cyanide copper plating

The cyanide-free alkaline copper plating of HEDP (hydroxyethylidene diphosphoric acid) system has been proved by practice that it can obtain better bonding force on aluminum alloy parts and iron parts. In terms of zinc alloy die-casting parts, through process improvement, such as Reduce the concentration of copper in the plating solution, reduce the working temperature of the plating solution, charge the tank, and use high-current electroplating for a short period of time after the tank to solve the problem of copper replacement, so that the performance of the coating can reach the level of cyanide copper plating. However, this The process can only be applied to a small part of zinc alloy die-casting parts with good die-casting quality, and the quality of die-casting depends on the rationality of mold design, the ratio of metal components in zinc alloy, the content of impurities, and the operating conditions of the die-casting process. The quality of some zinc alloy die castings is average, especially for zinc alloy die castings mixed with a certain amount of recycled materials, the use of cyanide-free alkaline copper plating is still unable to replace cyanide copper plating

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