Cyanogen-free plating method of zinc alloy die casting

Abstract

The invention discloses a cyanogen-free plating method of a zinc alloy die casting. The method is a plating method in which cyanogen-free copper-zinc alloy, copper-stannum alloy or ormolu is subjected to barrel plating or rack plating in a cyanogen-free copper-zinc alloy solution, copper-stannum alloy solution or ormolu solution as grounding layers so as to provide a pre-plating layer with good bonding force for subsequent plating or chemical plating. The method comprises the following steps: (1) carrying out ultrasonic wax removal or tumbling wax removal on a zinc alloy die casting blank; (2) washing; (3) chemically removing oil; (4) washing; (5) activating with 0.5% sulfuric acid; (6) washing; (7) carrying out barrel plating or rack plating on the alloys in the cyanogen-free copper-zinc alloy solution, copper-stannum alloy solution or ormolu solution; (8) washing; and (9) carrying out the subsequent plating or chemical plating. By using the method provided by the invention, cyanogen-free barrel plating or rack plating alloy is carried out on the zinc alloy die casting so that the obtained plating layer is semi-bright and has good bonding force.

Description

technical field [0001] The invention belongs to the field of electrochemical surface science and engineering, and in particular relates to a cyanide-free electroplating method for zinc alloy die castings. Background technique [0002] Cyanide copper plating has long been used as a base copper plating process for zinc alloy die castings, but cyanide is highly toxic and poses a serious threat to operators and the environment, making cyanide copper plating contrary to clean production. Therefore, cyanide-free electroplating is the future direction of development. Cyanide-free alkaline copper plating is the product of the national clean production development requirements, which largely eliminates the hazards of cyanide copper plating to operators and the environment. A lot of hard work has been done, and great progress has been made. [0003] However, compared with other substrates, the electroplating process of zinc alloy die castings is complicated, especially the cyanide-f...

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Problems solved by technology

(3) Zinc alloy cyanide-free electroplating is very difficult, especially copper plating, which often cannot meet the requirements of bonding force

(4) According to some literature reports, it needs to be charged into the tank during single metal plating, which brings inconvenience to the operation

[0004] In addition, cyanide-free barrel plating of zinc alloy die castings has not been applied in production so far. The outstanding problems are weak bonding force of the coating, unsightly coating, unsatisfactory dissolution of the anode during electroplating, friction and corrosion of the coating during the barrel plating process, etc.

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