Zinc-cadmium alloy composite coating of aerospace electric appliance accessory and preparation method of zinc-cadmium alloy composite coating

Abstract

The invention provides a zinc-cadmium alloy composite coating of an aerospace electric appliance accessory and a preparation method of the zinc-cadmium alloy composite coating, and relates to the technical field of protective materials. The zinc-cadmium alloy composite coating provided by the invention comprises a chemical zinc deposition layer, a nickel coating, a zinc-cadmium alloy coating, a silane chromate-free passivation layer and a graphene sealing layer which are sequentially arranged on the surface of an aluminum alloy matrix. The chemical zinc deposition layer and the nickel coating are arranged on the surface of the aluminum alloy matrix, so that the bonding strength of the zinc-cadmium alloy coating and the aluminum alloy matrix is improved; the zinc-cadmium alloy coating has excellent corrosion resistance, replaces a cadmium plating layer of a traditional aerospace part, and can greatly reduce pollution of cadmium to the environment; according to the zinc-cadmium alloy composite coating of the aerospace electric appliance accessory and the preparation method of the zinc-cadmium alloy composite coating, the silane chromium-free passivation layer is adopted to replace a high-toxicity hexavalent chromium passivation layer, so that the pollution of hexavalent chromium to the environment can be avoided; and the graphene sealing layer is arranged on the surface of the silane chromium-free passivation layer, so that the technical defect of poor weather resistance of the silane chromium-free passivation layer can be overcome.

Description

technical field [0001] The invention relates to the technical field of protective materials, in particular to a zinc-cadmium alloy composite coating for aerospace electrical accessories and a preparation method thereof. Background technique [0002] Aerospace electrical accessories are usually made of aluminum alloys, which require cadmium plating and hexavalent chromium passivation to prepare a highly corrosion-resistant protective layer. The use of trivalent chromium passivation in civilian galvanized and zinc-nickel alloys has made great progress, but the trivalent chromium passivation layer does not have self-healing properties and cannot meet the technical requirements of military products. Therefore, cadmium plating and other coatings of aerospace products have been passivated by hexavalent chromium, but there is a high pollution problem in hexavalent chromium passivation, which has a great destructive effect on human health and the natural environment. [0003] The p...

AI Technical Summary

Problems solved by technology

The use of trivalent chromium passivation in civilian galvanized and zinc-nickel alloys has made great progress, but the trivalent chromium passivation layer does not have self-healing properties and cannot meet the technical requirements of military products

Therefore, cadmium plating and other coatings of aerospace products have been passivated by hexavalent chromium, but there is a high pollution problem in hexavalent chromium passivation, which has a great destructive effect on human health and the natural environment.

[0003] The passivation layer prepared by solvent-based silane chromium-free passivation agent has self-healing properties (see Lai Huanwen, Guo Chongwu, "High Performance Chromium-free Passivation Technology", Electroplating and Environmental Protection, Issue 6, 2012: 35-37) , but this passivation layer has the disadvantage of poor weather resistance. White powder will appear on the surface after one year in the natural environment, resulting in a decline in corrosion resistance. Therefore, the use of this passivation agent to prepare protective layers for aerospace products is still Does not meet the requirements of the aerospace industry

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