What is gold plating

Electroplating

By energizing the product to be gold-plated, an electric current is generated in the plating solution and an electric field is formed to release electrons, which combine with gold ions and are finally deposited on the surface of the plated product to form a gold-plated layer. Compared with other electroplating processes, gold plating not only improves the electrical properties of parts, but also increases their wear and corrosion resistance.

Chemical Gold Plating

Chemical reaction is used for gold plating without the need of electric current. The commonly used chemical plating liquid contains gold ions, reducing agents and complexing agents, and the gold layer is deposited on the substrate through chemical reduction reaction. The advantage of chemical gold plating is that the plating layer is uniform and is not affected by the current distribution, which is suitable for workpieces with complex shapes.

Plating process steps

Pre-treatment: includes cleaning and degreasing to remove oil, oxides or other contaminants that may exist on the surface of the workpiece. Commonly used cleaning methods include acid washing, alkaline washing, etc.

Activation: Activate the surface of the workpiece through chemical solutions to ensure that the surface can effectively adsorb gold ions. Commonly used activation methods include acid or alkaline activation solution treatment.

Electroplating or chemical plating: The process of electroplating or chemical plating in a gold plating solution. This step determines the quality and thickness of the gold plated layer by controlling parameters such as current density, electrolyte concentration, temperature and time.

Post-treatment: This includes cleaning and drying. It removes excess metal salts and impurities from the gold plating process and ensures the uniformity and luster of the gold plated layer.

Advantages of gold plating

Good electrical conductivity: gold has excellent electrical conductivity, electroplated gold layer can reduce the contact resistance, to ensure good electrical contact of electrical components.

Strong corrosion resistance: gold has excellent chemical stability, which can effectively prevent the oxidation and corrosion of the contact components, especially in high humidity and corrosive environments.

Abrasion resistance: Although the hardness of gold is low, its surface is smooth and has good friction resistance, especially suitable for frequent contact components.

Good mechanical properties: The thin film of the gold layer enhances the scratch resistance of the component surface and reduces wear and tear.

Aesthetics: The electroplated gold layer has a glossy feeling, which can make the product more beautiful and high-grade.

Quality control of gold plating

Thickness control of gold layer: The thickness of gold layer of electroplating needs to be precisely controlled, and the common thickness of electroplating is 0.1-2 microns. Too thin a thickness will easily affect the corrosion resistance, while too thick may lead to increased costs or affect the performance.

Adhesion test: electroplated gold layer must have good adhesion, commonly used test methods are shear force test, peeling force test.

Appearance test: the uniformity, gloss and surface quality of the gold layer is an important part of quality control, usually using microscope observation, gloss meter, etc. for testing.

Electrical performance test: through the measurement of contact resistance, electrical conductivity and other indicators to ensure that the gold layer can meet the expected electrical performance requirements.

Roll and rack plating