The PCB nickel spraying process, is a surface finishing method that deposits a layer of nickel onto the copper pads of a printed circuit board to provide a durable, corrosion-resistant barrier. This process is often used as a base layer for other finishes (such as gold) or as a standalone coating in applications requiring high wear resistance and solderability.

The nickel spraying process typically begins with cleaning and preparing the PCB’s copper surface, similar to other plating processes. The nickel is deposited using techniques like electroless nickel plating or spray coating. Electroless nickel plating uses a chemical bath that autocatalytically deposits nickel onto the copper without the need for an external electric current, resulting in a uniform layer even on complex geometries. Spray coating, on the other hand, applies a nickel-containing solution via a high-pressure nozzle, which is then cured to form a solid layer. The thickness of the nickel coating ranges from 5-30 microns, depending on the application’s requirements.

Nickel provides excellent corrosion resistance, forming a passive oxide layer that protects the underlying copper from environmental factors like moisture, chemicals, and oxidation. This makes nickel-finished PCBs suitable for harsh environments, such as industrial machinery, automotive electronics, and marine equipment. Nickel also offers good wear resistance, making it ideal for connectors and contact points that undergo repeated mating and unmating.

When used as a base layer for gold plating (known as electroless nickel immersion gold, ENIG), nickel prevents diffusion between copper and gold, ensuring long-term reliability. This combination (nickel-gold) is widely used in high-reliability applications like aerospace and medical devices, where solderability and corrosion resistance are critical.

However, nickel has lower electrical conductivity compared to silver or copper, which can be a drawback in high-frequency applications. Additionally, improper plating can lead to issues like nickel whiskers, which are tiny conductive filaments that may cause short circuits. Despite these challenges, the PCB nickel spraying process is valued for its versatility and durability, making it a key technique in modern PCB manufacturing.