The Gold Plating PCB Process
Gold is a precious metal that has many beneficial properties. It is an excellent conductor of both heat and electricity. It is also resistant to corrosion from various substances.
It is highly durable and can be alloyed with cobalt and nickel to improve its hardness and wear resistance. This surface finish is typically used on edge connectors and keypads.
Resistance to Corrosion
Gold is a good conductor of electricity, and this makes it an ideal choice for printed circuit boards. It’s also resistant to corrosion and oxidation. In fact, it can handle high temperatures without being damaged. This is why many electronic components are plated with gold. The gold used for PCBs is usually plated by electroplating, a process that involves applying an electrical current to the surface that’s being plated. The electrical current causes negatively charged atoms on the surface to bond with positively charged gold ions. This creates a layer of gold less than 0.0000015 inches thick on the surface that’s being plated.
The plating process is very precise and requires strict standards to be met. The traces must be of a specific width and spacing, and the copper must be smooth. It’s also important to keep in mind that the surface finish of a PCB must be smooth and even. There are several different types of surface finishes on a PCB, including ENIG, hard gold, and soft gold.
Hard gold plating uses nickel as an underlayer to protect the copper and improve the rust resistance of the gold layer. It is also a good option for recurrent contact applications because it handles friction well. It’s easy to solder and has good oxidation resistance. It’s not as ductile as soft gold, though, and is harder to use in applications that require a lot of force.
Resistance to Friction
The gold plating pcb process has a number of meticulous steps to ensure that each circuit board that rolls off the production line is perfectly equipped to conduct signals free of error. During the process, each finger of the gold plate is carefully placed to match up with the corresponding slot on a motherboard. This is to ensure that the two fit hand-in-glove, allowing them to transfer data with minimal resistance. The process also includes rigorous inspections and defect tests, which are essential to the smooth operation of a PCB.
Gold is highly resistant to friction, making it a great choice for use in areas where force and friction are present. It is also less prone to fretting degradation, a condition where small oscillatory movements between two contacting surfaces result in material deterioration.
To enhance the durability of hard gold, it is often gold plating pcb coated with a nickel underplate. This layer helps bear the contact load of the gold deposit, reducing the likelihood of cracking. It also improves overall wear resistance.
The presence of non-noble elements in hard gold electrodeposits like cobalt and nickel can make it challenging to solder. These metals oxidize at soldering temperatures, which reduces the strength of the bond. In addition, nickel is sensitive to thermal shock. Consequently, it can become contaminated with nickel corrosion and black pad (Nickel blackening). To minimize these issues, a nickel underplate is required for hard gold plated components.
Resistance to Wear
Gold is a very durable material, so it’s ideal for PCBs that need to withstand repeated use. Its ductility and malleability also make it easy to shape into wires that can be easily soldered onto contact pads. This allows for a larger surface area, which can improve connectivity and increase reliability.
A gold-plated PCB can also resist abrasion and mechanical stress. Its thick coating also increases conductivity and resists corrosion and oxidation. This makes it the ideal choice for high-stakes applications like aerospace, military equipment and medical devices.
The most common process used to plate gold on a circuit board is electroless nickel immersion gold (ENIG). It uses an electrolytic solution to deposit a thin layer of nickel on the copper base. This layer is then covered with electroplated hard gold to protect the base from corrosion and provide superior adhesion.
The hard gold that is applied to the PCB is typically plated at a thickness Gold Plating PCB Supplier of 30 microns. It’s often used for the PCB’s edge connectors, which are also known as “gold fingers.” Because the contacts on a gold-plated PCB will be repeatedly installed and removed, it’s important to have a robust connection. This is especially true when working with high-speed signals, which can cause a lot of movement. Fretting degradation is a common concern with some types of metals, but gold is not susceptible to it.
Durability
Gold is completely immune to corrosion, so the contacts on a gold-plated circuit board won’t wear down quickly. It also doesn’t react with chemicals, rust or other metals. This durability makes it a good choice for metal-to-metal connections on a PCB, but it’s not ideal for solderable areas. For these applications, you should use electroplated hard gold (ENIG) instead. This finish is more robust than pure gold and won’t oxidize easily, making it better for high-wear areas on a PCB.
You can find hard-gold PCBs in a variety of devices and equipment, including computerized industrial machines. They’re used to send signals from peripheral devices to motherboard cards, which then communicate with other machines. They’re also common in telecommunication systems.
This type of PCB has excellent conductive properties and can withstand harsh conditions like humidity, temperature, and chemical exposure. It’s often used in military hardware, as it’s capable of resisting corrosion and oxidation better than traditional copper boards.
The gold plating process on a PCB involves a few steps: activation, pickling, cleaning, microetching, auto-catalytic nickel plating, and electroless gold plating. The final step involves beveling the connector edges. The gold is usually enhanced with cobalt for boosted surface resistance. The process allows for a thinner layer of gold than conventional nickel. This reduces the risk of short circuiting and increases the strength of the contact points.