The main differences are the application process, layer thickness, and performance characteristics. Gold plating is an electrochemical process that creates a thicker, harder, and more durable layer, ideal for high-reliability applications, while immersion gold uses a chemical process to create a thinner, more uniform layer that is flatter and more cost-effective for standard use, such as for fine-pitch components.

What is gold plating?

Gold plating is the entire board. It generally refers to electroplating, electroplated nickel-gold[^1], electrolytic gold, electroplated gold, and electroplated nickel-gold. There are soft gold and hard gold (commonly used for gold fingers). The principle is to dissolve nickel and gold (commonly known as gold salts) in a chemical solution. The circuit board is immersed in an electroplating tank and an electric current is passed through it to form a nickel-gold coating on the copper foil surface of the circuit board. Electroplated nickel-gold is widely used in electronic products due to its high hardness, wear resistance, and resistance to oxidation.

What is immersion gold?

This coating is formed through a chemical redox reaction. It is generally thick and is a type of chemical nickel-gold deposition[^2] method. It can achieve a thick gold layer and is commonly called immersion gold.

Differences between immersion gold and gold-plated PCBs

1. The crystal structures formed by immersion gold and gold plating are different. immersion gold allows for much thicker gold than gold plating, resulting in a more golden yellow color and greater customer satisfaction.

2. The crystal structures formed by immersion gold and gold plating are different. immersion gold is easier to solder than gold plating, preventing soldering defects[^3] and customer complaints. immersion gold PCBs have easier stress control, making them more convenient for bonding products. Also, because immersion gold is softer than gold plating, immersion gold PCBs are less wear-resistant for gold fingers.

3. immersion gold PCBs only have nickel-gold on the pads. The skin effect prevents signal transmission through the copper layer, preventing signal degradation.

4. immersion gold has a denser crystal structure than gold plating, making it less susceptible to oxidation.

5. With increasingly dense wiring, line widths and spacings have reached 3-4 mils. Gold plating is more susceptible to gold wire shorts. Immersion gold (Immersion Gold) boards only have nickel-gold on the pads, preventing gold shorts.

6. Immersion gold boards only have nickel-gold on the pads, ensuring a stronger bond between the solder mask and the copper layer. Compensation during construction will not affect spacing.

7. Immersion gold is generally used for boards with relatively high requirements for flatness. It generally avoids the black pad phenomenon[^4] after assembly. Immersion gold boards offer the same flatness and longevity as gold-plated boards.

[^1]: Discover the importance of electroplated nickel-gold in electronics and its role in durability and performance.
[^2]: Understand the process of chemical nickel-gold deposition and its applications in creating reliable electronic components.
[^3]: Gain insights into soldering defects and learn strategies to prevent them for better PCB assembly.
[^4]: Explore the black pad phenomenon to understand its impact on PCB reliability and how to mitigate it.