Hard Gold Plating

Plating in hard gold requires non-noble metal elements to be alloyed into the deposit – typically cobalt, nickel or iron. This hardens the deposit and makes it far more resistant to sliding wear and contact switching.

A nickel underplate also helps bear the contact load of a hard gold deposit, reducing the risk of cracking and improving surface finish. This can be especially important if the application will encounter a high normal force of contact.

High Corrosion Resistance

Gold is one of the most corrosion-resistant metals, able to resist acids and exposure to other elements. It is also immune to tarnish and will not degrade under normal conditions. However, this property can be negated by abrasion.

Plating with hard gold is typically less resistant to abrasion than soft gold because it is actually an alloy of gold and other metals. The alloying process makes it harder than pure hard gold gold, making it more appropriate for areas that are exposed to force and friction.

It is important to consider the end-use of a product when deciding whether hard or soft gold electroplating is best. For example, an item that will be used in the mouth may be better served with soft gold since it is more durable against acid and other contaminants.

Another factor in the resistance of hard gold is the level of porosity. When a gold finish is porous, pollutants can enter the base metal of the substrate and cause corrosion. This can be improved by coating the gold with a barrier layer such as nickel. This will prevent the oxidation of the nickel underplate and help to maintain the durability of the gold finish. A layer of copper is also often added to a hard gold deposit because it creates an additional diffusion barrier and reduces the amount of pores present.

High Wear Resistance

Hard gold plating is the best option when you require a high degree of wear resistance. It offers a finer grain size which is capable of resisting sliding wear more effectively than soft gold deposits. It also lacks non-noble elements such as nickel and cobalt that oxidize at soldering temperatures and can compromise the strength of the resulting solder joint. Soft gold, on the other hand, has more metal impurities which enhance its corrosion resistance but also decreases its ability to be used for soldering applications like ultrasonic wire bonding and thermosonic bonding.

We have conducted a number of tests to determine the relative performance of hard and soft gold. These tests evaluated the corrosion and abrasive wear resistance of a plated sample in real world conditions. The test sample was placed into three different solutions that mimicked typical corrosive environments: artificial sweat (35 g NaCl), salt water, and dilute sulphuric acid. The results showed a steady mass loss over time that is consistent with real life use.

Electrolytic nickel electroplated hard gold performs well under normal contact force. This finish is typically used for edge connectors and keypads on PCBs. This is due to the fact that it consists of an electrolytic gold coating over a barrier layer of nickel. This combination of high contact resistance and wear-through performance allows for a larger number of cycles than would be possible with soft gold alone.

Low Contact Resistance

Unlike copper, which interacts with oxygen to create hard oxides that have insulation properties, gold does not react with oxygen and instead has a very low resistance. This makes it ideal for projects that require regular sliding wear, and it is able to power through many actuation cycles without breaking down.

Because of this, it is able to provide significant cost savings through its longevity and durability. It also reduces the need for replacements, repairs, and downtime. This can have a positive impact on a company’s reputation with customers and minimize costs related to lost production.

In addition, it is superior to nickel plating for medical applications that require biocompatibility. It is also an excellent choice for electronic connectors that are used in vibration environments where serious fretting disturbances can occur at the contact interface.

To make sure that a PCB has an optimal lifespan, it is important to choose a manufacturer with experience and expertise. This will ensure that the board is plated with an adequate thickness and will not wear down prematurely. In addition, the company should have a quality assurance process to ensure that all parts are up to standards. It is also a good idea to select a manufacturer that offers excellent customer service and communication. This will help ensure that the manufacturer can meet all of your project’s requirements and deliver a quality product on time.

Excellent Surface Finish

The incredibly fine-grained surface finish of hard gold gives it tough resistance to friction. This makes it the ideal surface finish for high wear areas such as the gold/edge fingers on PCBs, which typically experience thousands of mating cycles each day. It also offers excellent resistance to scratching.

In contrast, soft gold Hard Gold PCB Supplier has a less fine-grained surface finish and is therefore more susceptible to scratches and abrasions. This may lead to decreased reliability and signal integrity.

Another important consideration is the type of underplate used with each plating process. The metal under the gold can add significant functional benefits to soldering and bonding, or it could compromise these qualities. For example, unbright electrolytic sulfamate nickel or bright medium phosphorous electroless nickel underplates for hard gold deposits can result in an extremely glossy appearance that is cosmetically desirable, but they can cause oxidation and compound formation with copper at elevated temperatures.

This can weaken the bond between copper and gold, resulting in poor solderability and possible failures of the joint. A high-quality ENEPIG finish (gold over nickel) on the other hand, provides good corrosion resistance and excellent tarnishing/tarnish resistance, while maintaining a smooth, flat surface that’s ideal for SMT and BGAs. Moreover, ENEPIG is a low-cost solution that’s become popular in recent years due to accountability for RoHS regulations.