A method for stripping the nickel-phosphorus coating on the surface of a workpiece

Abstract

The invention discloses a method for deplating a nickel-phosphorus coating on the workpiece surface, characterized by preparing a deplating liquid and putting the workpiece in the deplating liquid to deplate. According to the invention, the method guarantees that after deplating nickel-phosphorus coatings in various proportions on copper alloy or aluminium alloy base materials, the surface of the base material is slightly etched and the fineness is not influenced, and the method is suitable for all copper alloy and aluminium alloy and solves the problems of low quality and low efficiency of deplating high-phosphorus nickel-phosphorus coatings on copper alloy or aluminium alloy, and corrosion to the base materials in the prior art; in addition, compared with common nickel-phosphorus coatings, the method disclosed herein can achieve a total amount of deplated coatings which is more than 10 times that obtained by traditional method, thus the efficiency is greatly raised.

Description

technical field [0001] The invention relates to a deplating process, in particular to a method for deplating a nickel-phosphorus coating on the surface of a workpiece. Background technique [0002] Nickel-phosphorus alloy plating on copper alloys has been widely used in the surface coating of electronic connector shells, the gold-plated bottom layer of the inner and outer conductors of electronic connectors, and the high-temperature nickel bottom layer of tin-plated soldering terminals of electronic connectors. Copper alloys are plated with high-phosphorus nickel, which can be used in seawater for a long time, with a service life of more than 50 years; high-phosphorus nickel is used as the gold-plated bottom layer of electronic connectors, which can greatly improve the product’s resistance to nitric acid vapor and corrosive mixed gases; high-temperature nickel (ie Nickel-phosphorus alloy with low phosphorus ratio) is used as the bottom layer of tin plating, which can greatly...

AI Technical Summary

Problems solved by technology

Common acidic electrolytic nickel stripping solutions are only suitable for low-phosphorus nickel coatings on copper alloys, but cannot be removed at all for high-phosphorus nickel; acidic chemical nickel stripping solutions generally only remove phosphorus-free nickel on copper alloys; The nickel stripping solution can remove the medium and low phosphorus nickel on the copper alloy. Some commercial stripping solutions that claim to be used for high phosphorus nickel have been verified to have very low stripping efficiency, and cannot guarantee that the surface of the workpiece substrate will not be corroded; nitric acid can strip In addition to high, medium and low phosphorus nickel coatings on aluminum alloys, it is very suitable for industrial pure aluminum, but it is easy to cause over-corrosion to duralumin (aluminum-copper alloy), and the substrate lattice is completely exposed after the coating is removed.

After the substrate has faded and corroded due to the coating, it is often required to be mechanically processed again, and the construction period is often very long. Some materials are specially made, and the production cycle is even more difficult to guarantee.