For decades, manufacturers of electronics products have used gold plating to protect the connectors that are essential for joining electrical circuits together. Gold is the preferred material because of its good electrical conductivity, ability to resist corrosion and wear and excellent heat-shielding properties. Determining the appropriate gold plating thickness is a vital decision to maximize the durability and life cycle of the connector.
The Process of Gold Plating Connectors
Gold plating involves the application of a layer of gold via electrodeposition onto a workpiece to enhance the surface of the finished product. When plating electrical connectors with gold, it’s advisable to apply an undercoating of another metal, typically nickel, to prevent the degradation of the top layer of gold. Nickel plating provides the following benefits:
- Inhibiting corrosion: Nickel works in conjunction with the gold layer to prevent porosity that can lead to corrosion. Electroless nickel plating, which applies the coating via an autocatalytic reaction instead of electrodeposition, is typically the best method for sealing the base material.
- Forming a diffusion barrier: Electrical connectors often consist of copper or a copper alloy, which can diffuse into the gold coating and cause it to weaken. A nickel underplate forms a protective barrier that will prevent diffusion from occurring.
- Acting as a leveling agent: Applying a nickel base coat will produce a smoother surface finish that reduces friction. Consequently, the gold-plated connector will feature increased wear resistance and last longer.
- Strengthening the foundation: A layer of nickel will harden the surface of the substrate and the gold deposit. The finished product will be less susceptible to cracking, chipping and other issues that can shorten its life span.
Determining the Appropriate Gold Electroplating Thickness
The thickness of gold plating can vary significantly. It’s possible to apply a gold coating ranging from very thin (5uin to 100uin) to extremely thick (500uin to 1000uin). While a thicker layer will decrease the workpiece’s porosity and enhance corrosion protection, an excessively thick layer can cause embrittlement in a solder joint, resulting in a loss of ductility. On the other hand, a coating that’s too thin may not provide sufficient corrosion and wear resistance.
Cost is another factor when considering the ideal gold plating thickness. As a precious metal, gold can be one of the most expensive plating materials, which may result in a higher project cost. As a rule of thumb, start with a thickness level that’s as low as possible for your application, then increase it if necessary.
Gold Plating Thickness Guidelines
Use the following gold electroplating thickness breakdown to help you determine the best level for your manufacturing applications:
- Thin: A thin gold coating in the 4uin to 0uin range will work well for low-contact applications or when you require excellent solderability. Consider this level when using connectors in a controlled environment where wear resistance is not an issue. Examples of workpieces that will benefit from a thinner gold finish include solder pads, studs and grounding nuts.
- Moderate: Consider a moderately thick gold coating between 30uin and 50uin for workpieces that face exposure to ordinary amounts of environmental corrosion or wear cycles, as well as when soldering connectors. While this level will not prevent porosity entirely, it will provide sufficient barrier protection where repeated condensation cycles are not present or the risk of chemical attack is low. Typical applications include gold-plated contact springs, sockets and beryllium copper flex contacts.
- High: Apply a thicker gold layer between 50uin and 100uin for workpieces exposed to aggressive environments where corrosion and chemical attack pose a substantial risk. This level will also increase wear resistance in moderate to high-cycle settings. Examples include mil-spec applications in the oil and gas industry, as well as thermal and switching cycles.
- Extreme: A gold layer of 100uin or more creates an entirely pore-free layer that provides maximum corrosion protection for applications of 10,000 cycles or higher. It will also increase the workpiece’s durability in high-wear applications. Avoid this thickness level when soldering due to the increased risk of embrittlement.
SPC: Your Headquarters for Gold Electroplating
SPC is a family-owned and operated company that’s been delivering expert metal finishing solutions for electronics and other industries for more than 90 years. We’ve developed an industry-best gold electroplating method we can customize to your industry and applications. We have extensive experience with gold plating connectors — trust us to determine the most functional and cost-effective gold electroplating thickness for your design and manufacturing processes.
Contact us to learn more about the benefits of gold plating connectors and request a no-obligation project quote today.