Heat treatment type conductive film forming method on passivation light metal

Abstract

The present invention provides a method for forming a heat-treated conductive film on a passivation-forming light metal, which is to form a conductive film such as silver, copper, tin, etc. on a passivation-forming light metal selected from aluminum, magnesium, and titanium through a base film. A coating method, the base coating is a nickel-phosphorus coating, the base coating is formed by using a nickel-phosphorus electroplating bath containing a prescribed soluble nickel salt, a phosphorus-containing compound, a complexing agent, a surfactant, a buffer, and a brightener, And heat-treating the base coating, or the base coating and the conductive coating under conditions including a low temperature range of 30°C or higher, can strengthen the adhesion of the base coating to the passivation light metal compared to a method without heat treatment. A conductive film is formed on the passivation-forming light metal more firmly.

Description

technical field [0001] The present invention relates to a method for forming a conductive film on specific light metals such as aluminum and magnesium that are prone to form passive states. According to the present invention, there is provided a method of forming a conductive film of copper, silver, tin, etc. with strong adhesion on the above-mentioned light metal that is difficult to form a plated film by applying heat treatment. Background technique [0002] Specific light metals such as aluminum, magnesium, and titanium tend to form a strong oxide film in the atmosphere and become passive. Therefore, even if it is desired to form a conductive film such as copper, silver, and tin on the surface of these light metals, it is difficult to pass it through plating. for surface treatment. In addition, even if a plated film can be formed, it is difficult to ensure good adhesion with the above-mentioned light metal. [0003] Therefore, conventionally, the above-mentioned light m...

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Problems solved by technology

However, especially in the above-mentioned secondary zinc dipping method utilizing the substitution reaction of zinc and aluminum, there is a problem that since the particles of the zinc film formed initially are large, it is necessary to peel them off and then form a film from the zinc particles again, which is not only cumbersome to process. The productivity is not good, and the treated surface is relatively rough, making it difficult to form a smooth film in subsequent electroplating

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