Types of Hard gold PCB

A Hard Gold PCB (Printed Circuit Board) refers to a circuit board that has a layer of gold plated over its surface. Gold is used as a coating material for specific areas of the PCB, usually on the contact points or pads, where electrical connections are made. There are two main types of gold finishes used in PCBs: soft gold and hard gold.

Hard Gold vs. Soft Gold:

1. Hard Gold:

  - Composition: Hard gold is composed of a higher percentage of gold alloyed with other metals like cobalt or nickel. This alloy provides increased durability and wear resistance.

  - Use: Hard gold is commonly used in applications where the contacts will be frequently mated and de-mated, such as connectors and switches. It is ideal for situations where there is a need for repeated cycles of connection and disconnection.

  - Thickness: The thickness of hard gold coatings is generally greater than that of soft gold.

2. Soft Gold:

  - Composition: Soft gold has a higher percentage of pure gold with little or no alloying. It is softer and more malleable than hard gold.

  - Use: Soft gold is often used in applications where the contacts are less frequently mated and de-mated. It is suitable for situations where the gold coating needs to be thinner.

  - Thickness: Soft gold coatings are typically thinner than hard gold coatings.

Advantages of Hard Gold PCBs:

1. Durability: Hard gold provides better durability and wear resistance compared to soft gold. This makes it suitable for applications with high mating cycles.

2. Wear Resistance: The alloying elements in hard gold contribute to its wear resistance, making it less prone to damage during repeated connections.

3. High Cycle Life: Hard gold is well-suited for applications that require a high number of mating cycles, such as connectors in frequently plugged and unplugged devices

Applications:

Hard gold PCBs are commonly used in various applications, including:

1. Connectors: Hard gold is frequently used in connector pins and sockets for applications such as USB connectors, HDMI ports, and other interface connections.

2. Switches: Hard gold-coated contacts are suitable for switches where repeated actuation occurs.

3. Test Points: In PCBs used for testing and debugging electronic circuits, hard gold is applied to test points for better conductivity and longevity.

When designing a PCB with hard gold finishes, it's important to consider the specific requirements of the application, the number of mating cycles expected, and the overall durability needed for reliable performance over time.