After completing the pre-treatment preparation for aluminum electroplating, the next step is the electroplating process itself.

Regardless of which pre-treatment method is used, the first step after pre-treatment is copper flash plating.

(1) **Copper Flash Plating**

The plating solution most commonly used for copper flash plating is the cyanide copper plating process. After completing the copper flash plating, it must be thoroughly cleaned and activated. Activation is done with a 1% to 3% sulfuric acid solution. If the subsequent electroplating is acidic copper plating or nickel plating, the workpiece can directly enter the plating tank after activation without rinsing. However, if the subsequent plating uses other alkaline solutions, particularly cyanide-based solutions, two rinse steps must be performed after activation before entering the plating tank.

(2) **Intermediate Plating Layer**

After the copper flash plating, an intermediate plating layer is applied according to the product design or process requirements. The intermediate plating layer can be considered as a base layer. Copper flash plating is a technical layer used to ensure dispersion ability and adhesion strength. To meet the product's coating requirements, the intermediate plating layer must be selected according to the final surface coating.

For example, acid copper plating, dark nickel plating, or other coatings suitable as intermediate or base layers can be used. If the surface coating is silver, the copper flash plating must be thickened appropriately, such as by using acidic bright copper plating. Afterward, the workpiece must undergo a silver flash plating (or electroless silver plating) before applying the final surface coating. In the general processes discussed in this chapter, copper, nickel, and other plating methods can be used as intermediate layers for aluminum electroplating.

(3) **Surface Coating**

The surface coating is the target coating required for aluminum electroplating. It can be either decorative or functional. For electronic electroplating, aluminum electroplating is mostly functional, with only a few exterior parts serving both decorative and functional purposes. Purely decorative coatings are limited to exterior parts like handles, knobs, and nameplates.