Leadless hard gold plating technology is a technique that does not require additional leads to complete the gold plating process. It is typically used in the manufacturing of high-density, high-precision electronic products, particularly in miniaturized designs, where it offers significant advantages.

Key Features:

   1. Leadless design: Traditional electroplating processes typically require leads to connect to the electroplating area to ensure proper plating. However, in leadless gold plating technology, the entire copper layer on the board acts as a conductor, allowing current to flow smoothly during the electroplating process. The unnecessary portions are then etched away.

   2. Gold plating first, then etching: Unlike conventional electroplating, this process involves applying gold plating on the entire copper surface before circuit etching. This means the gold layer covers all copper areas, and the excess material is removed through etching, leaving only the required circuits and pads. This method simplifies the plating process and is particularly suitable for leadless components and high-density PCB designs.

   3. Electrochemical corrosion risk (Galvanic effect): Since leadless gold plating covers the entire copper surface, during circuit etching, the bottom of the pads may be exposed to etching solutions, leading to a potential difference between the gold and copper. This can cause a galvanic effect (electrochemical corrosion). Special measures must be taken during design and manufacturing to mitigate this effect and prevent pad corrosion.