Benefits of Gold Plating on PCBs
Gold-plated PCBs are immune to corrosion from chemicals and rust. They are also resistant to mechanical wear and tear.
Nickel is plated first, followed by 1-2 microns of hard gold. This gold is usually alloyed with cobalt for boosted surface resistance. The connector edges are beveled at precise angles for easier insertion into their corresponding holes.
Durability
Gold is an excellent material for PCBs due to its strength and durability. It also offers a number of other benefits, including resistance to corrosion and oxidation, good solderability, and improved signal performance. These features make it a cost-effective solution in the long run, allowing manufacturers to minimize replacements and repairs.
Hard gold plating is usually applied to high-wear areas on a PCB, such as the edge connector fingers (also known as golden fingers). This type of plating is more durable than soft gold and requires less maintenance over time. It can also be alloyed with nickel or cobalt to increase its wear resistance.
Another benefit of hard gold is that it resists fretting degradation. Fretting is a phenomenon that occurs when two metals contact and rub together over a long period of time. This can damage the contact area and lead to failure of the device. However, gold is not susceptible to this condition because it is harder than copper.
The process of applying hard gold to a PCB begins with a nickel layer, which is then electroplated with a thin coating of gold. The nickel protects the gold from oxidation and reduces the likelihood of discoloration. In addition, nickel has a lower electrical resistance than copper, which improves conductivity. Lastly, the resulting layer of hard gold is much stronger than a soft gold surface and can withstand more abrasions.
High-Temperature Resistance
Gold plating is a popular option for PCBs gold plating pcb because it offers excellent conductivity and corrosion resistance. It also prevents oxidation and has high-temperature resistance. This makes it a great choice for applications that need to operate in harsh environments, like aerospace and military equipment. In addition, it reduces the noise between traces and improves signal quality.
PCBs plated with hard gold have a consistent surface finish and are very resistant to wear. This is especially useful along the connector edges that are often plugged in, unplugged, and reinserted. It also increases the lifespan of the Printed Circuit Board by preventing fretting corrosion.
The plating process involves using an electrolyte to deposit a layer of gold on the copper surface of the circuit board. The electrolyte consists of a weak organic acid and its resultant salts, along with metallic brighteners in chelated or complexed form. It can also include range extenders, depolarizing agents, and surfactants. The final product is a smooth, even coating that can be etched or printed with ease.
If you’re looking for a more durable gold finish, opt for ENIG instead of flash gold. ENIG is more cost-effective than gold plating, and it’s also much harder to oxidize. However, be sure to place plated holes (PTH), SMDs, and silk screens far enough away from the gold fingers to avoid short-circuiting.
Low-Porosity
The conductive nature of gold makes it a desirable material for PCBs. It has many benefits, including low porosity, high wear resistance and corrosion resistance. It is also a cost-effective alternative to silver and copper. Unlike copper, gold is able to handle stress and friction. This is why it is often used for contact surfaces, such as those found on membrane switches.
It is important to use a nickel underplate before PCB hard gold plating. This step is necessary to improve the hard gold’s durability. Popular underplates include bright electrolytic nickel, high purity sulfamate nickel and electroless nickel. These underplates prevent the diffusion of copper and other alloying metals into the deposited gold. In addition, they can also reduce the risk of pore corrosion in harsh environments.
The nickel layer also helps to protect the underlying copper from corrosion. Plating directly on copper will cause the gold to diffuse Gold Plating PCB Supplier into the substrate. This will eventually lead to a loss of contact with the base material and can cause the nickel layer to migrate to the surface of the copper.
The cyanide-free immersion gold plating bath has a longer bath life of 12 metal turnovers (MTO). This is a significant improvement over existing cyanide-free baths that have only 5 MTO. In addition, the bath is stable in heat idling tests and shows no thermal decomposition.
High-Conductivity
Gold is a metal with exceptional conductivity, so it’s no surprise that it’s used as a coating for PCBs. It’s also known for its durability and oxidation resistance. It’s a great choice for printed circuit boards that need to survive harsh environments.
When plated above an underlying material, like nickel or copper, gold is durable and resistant to corrosion. However, if it’s plated directly on copper, it’ll quickly wear away due to high-pressure sliding insertion/removal applications. This is why it’s typically plated above an underlying copper layer in the PCB fabrication process.
The thickness of the gold layer is an important factor in the durability of a PCB’s touch and slide contacts. Hard gold is capable of handling up to 1,000 cycles without wearing down. It’s also less prone to fretting degradation, which can occur when two contacting surfaces are subjected to oscillatory movements or rubbing over an extended period of time.
However, hard gold is more expensive than ENIG. It may be worth the added expense for manufacturers who face a lot of complaints about poor soldering quality or for those who want to save time in their assembly line. The extra convenience of using hard gold for touch and sliding contacts can be worth the price for many producers. However, for some, the disadvantage of having to apply more heat in order to solder a board with hard gold may outweigh its benefits.