Plating Metals On Refractory Metals in Electrical Connectors

Electroplating Precious Metals Onto Refractory Metals in Electrical Connectors

There are many uses of electroplating in electrical connectors, from improving corrosion resistance and electrical conductivity¹ to increasing strength and longevity. Electroplating processes allow for a more conducive and reliable surface metal²to be added to a substrate and enable manufacturers to benefit from the plating metals’ advantages without the cost³ of creating electrical connectors entirely from precious metals.

The consumer electrics market alone generated a revenue of $987 billion⁴ in 2022, and maintaining the quality of electrical connectors and other components is essential in manufacturing these products. As people become more reliant on their technology every day, they expect quality and longevity in items such as cell phones, computers and smartwatches. Manufacturers must balance growing consumer needs for quality with the cost of mass-producing electrical components, and electroplating precious metals onto refractory metals — those resistant to heat and wear⁵ — provides the perfect balance between resilience and quality.

Electroplating is one of the most critical processes in manufacturing electronic components. However, the process can be delicate due to the size and complexity of the parts. Working with an electroplating expert⁶ is the best way to find suitable precious metals for your application and ensure efficient production.

Why Do We Plate Connectors in Electrical Components?

Electrical contact plating is critical in keeping device components functioning correctly over time. Electrical components rely on stable contact materials⁷, like precious metals, to provide reliability and longevity in performance. Precious metals like gold⁸ are commonly used in electrical connector applications due to their tarnish resistance and stability in the unique circumstances required by electrical components.

There are several choices regarding the appropriate plating for electrical components. Other noble metals such as silver, palladium and rhodium all have electrical component applications. They are corrosion-resistant and improve conductability⁹. Factors like environmental humidity, electricity transfer, and wear and tear influence the choice of plating metal¹⁰. In some cases, multilayer systems can reduce precious metal usage¹¹.

Regardless, the cost of these materials can be prohibitive. Using refractory metals such as tungsten¹²provides a cost-effective base, and electroplating is a popular method for applying precious metal contact finishes in high-volume manufacturing.

In short, plating connectors is essential in manufacturing electrical components, enhancing their performance, reliability and durability in electronic systems. Reliable components lead to satisfied customers and enhanced reputation, which is vital to maintaining a competitive edge in the digital age. Many manufacturers constantly seek the highest quality and most reliable electroplating options to improve their products.

The Benefits of Electroplating for Electronic Contacts and Connectors

Electroplating adds a step — and additional costs — to the manufacturing process. However, the benefits outweigh the costs and labor. Some of the many benefits of electroplating for contacts and connectors include the following:

Improved Corrosion Resistance

Electroplating a layer of metal with strong oxidation resistance onto a base metal can improve contact corrosion resistance¹³ when exposed to moisture or harsh environments. In applications where rust prevention is vital, noble metals and some passive metals like nickel are plated to enhance the longevity of electrical components.

For example, copper is highly conductive but prone to corrosion¹⁴. Using iron or iron alloy as an underplate and plating it with corrosion-resistant options like gold or nickel prevents corrosion without impacting conductivity.

Enhanced Electrical Conductivity

Surface oxides can form on a contact¹⁵ or connector, inhibiting its ability to conduct electricity. Contact plating with metals containing anti-oxidation properties can prevent this surface formation¹⁶. Many precious metals also offer a smooth finish¹⁷ in plating, enabling a solid connection with the mated surface and limiting signal interruptions in electrical components.

Many base metals are strong and resilient for electrical components, as they resist wear and tear. Plating with highly conductive metals shields the base metals from the atmosphere and reduces electrical resistance¹⁸, leading to better conductivity and improved performance in electrical components.

Low Contact Resistance

Contact resistance is the resistance at electrical connection points¹⁹ that opposes the flow of an electric current. Surface irregularities, such as tiny scratches or rough spots, can form in these connection points due to repeated mating and unmating cycles. Over time, this wear and tear create greater contact resistance, impeding the electric signals.

Electroplating electric contacts and connectors creates a smooth surface finish, significantly reducing contact resistance. The electric signals encounter fewer obstacles as they travel through the components. Again, noble metals with anti-oxidation properties help keep contact surfaces smoother for longer, increasing the longevity of electrical components.

Improved Solderability

Electroplating can enhance solderability in electric components. Metals bond better when easily wetted²⁰ during manufacturing, providing more reliable circuits. Precious metals are often more suited for soldering and welding than base metals, improving manufacturing and producing a more robust end product.

Increased Protection From Wear and Tear

Some electrical components need to perform in harsh environments or mate frequently. Any external forces, such as temperature, humidity, friction and overuse, can impact the performance of electric items²¹. Electroplating with a metal resistant to such wear and tear²² protects the metal conductor, improves the durability of components, and prolongs the contact life span.

If electrical components are frequently exposed to high temperatures, the heat can damage the contacts²³ without the additional protection provided by electroplating. Precious metals such as gold and silver can protect contacts²⁴from high temperatures.

Enhanced Electroplating Adhesion

Adhesion — the ability of metals to bond²⁵ with one another — is essential in creating reliable and functional electrical components. Electroplating promotes adhesion by enhancing or altering the properties²⁶ of metal parts by placing the substrate in an electrolyte solution. This process improves adhesion, reducing flaking in the plating and protecting the base metal beneath.

Optimized Compatibility

Galvanic corrosion can occur when two metals come into contact²⁷ due to different electrochemical potentials. This corrosion can degrade electrical components and ultimately lead to equipment failure.

Compatability is particularly important in complex electrical systems with multiple moving parts. Electroplating with a compatible noble metal like gold or silver optimizes the compatibility of connectors²⁸ with the surrounding components, limiting galvanic corrosion, providing more reliable electrical connections and prolonging the life span of the parts.

Improved Coating Application

Successful electroplating relies on applying a very thin metal coat onto electrical contacts. If a coating is too thick, it can impede contact performance. Precious metals like gold are highly malleable²⁹, making applying the required thin coating more straightforward. In addition, applying the thinnest layer possible is more cost-effective³⁰, as you use less metal.

Types of Contact Plating for Connectors

There are several different types of contact plating³¹. Certain metals may be more suitable for specific components and environments depending on the application. Some of the most common types of contact plating include the following:

Nickel Plating

Nickel is a passive metal commonly used in electroplating as it’s suitable for many applications³². It’s hard, durable and corrosion-resistant³³ and withstands significant wear and tear. Extreme heat treatment and diamond composites can fortify³⁴ the metal further.

This metal is a perfect option for high-use components³⁵, as it can withstand additional pressure and resist damage from the elements. Its high electrical conductivity and ability to achieve an even coating make it a popular choice. It’s also an economical option³⁶ for improved corrosion resistance.

Gold Plating

Gold is a precious metal and one of the most sought-after choices for electric plating³⁷. It’s incredibly conductive even at low voltages³⁸and highly resistant to oxidation and corrosion, making it suitable for humid environments and frequent thermal cycling. Gold is tarnish-resistant³⁹, easy to bond and solder, and has low and stable contact resistance⁴⁰.

It is suitable for many applications and specifically helpful in creating springs and flexible connections⁴¹ in electrical components. It’s also non-magnetic, making it ideal for medical applications like magnetic resonance imaging⁴² (MRI) scanners. Gold is a premium choice⁴³, so one of the drawbacks of using it is the cost. It is expensive compared to other options, but being highly malleable allows users to reduce the amount used in plating.

Silver Plating

Silver offers another highly conductive plating option⁴⁴without the additional cost of gold, making this precious metal perfect for larger components. It’s slightly harder than gold and performs well in high-power electricity applications⁴⁵. Silver is a metallic lubricant ideal for threaded⁴⁶or sliding contacts.

This ductile and malleable metal also has antimicrobial properties⁴⁷, making it suitable for many medical applications. Silver is an excellent plating option for many uses but provides relatively poor corrosion protection⁴⁸.

Tin Plating

Tin is a cost-effective plating option⁴⁹ with some corrosion resistance, although it can be re-flowed for increased corrosion protection⁵⁰. This metal is best for applications with relatively low mating cycles and is unsuited for continuous service at high temperatures.

Tin is an environmental choice, as it is Restriction of Hazardous Substances⁵¹ (RoHS) compliant. It has low contact resistance and good solderability, making it an excellent low-cost option⁵².

Palladium Plating

Palladium is a noble metal⁵³, highly resistant to corrosion. It’s harder than gold or silver, making it extremely durable⁵⁴ in high-stress environments. It’s common practice to build deposit thickness with palladium and flash a small layer of gold⁵⁵ for contacts and connectors.

This precious metal is commonly used⁵⁶ for catalytic converters because it absorbs hydrogen. It has low surface contact resistance and is better suited to applications without acid exposure, as it’s susceptible to certain acids⁵⁷. It’s also best for applications with relatively low heat, as it has a low melting point⁵⁸ and limited heat resistance.

Palladium Nickel Plating

This alloy originated as a cost-effective alternative to gold. It’s a robust plating alternative⁵⁹ suited for applications that require durability and lightweight components⁶⁰. It’s less sensitive to fluctuations in the plating process and often flashes with gold to add lubricating properties and better corrosion resistance, and it provides a lightweight coating that resists corrosion and cracking.

Palladium nickel has low contact resistance and good solderability. It’s highly durable, withstands many mating cycles and performs well in high-heat environments. However, palladium nickel is better suited to applications where components don’t move against each other, as it has a higher friction coefficient⁶¹ than other metals, which can result in fretting — wear at the asperities of contact surfaces.

Rhodium Plating

Rhodium is an extremely hardy plating option⁶² suitable for applications that require acid resistance. It’s stronger than palladium and has high electrical conductivity⁶³ and impressive corrosion resistance. It also has low and stable contact resistance and is chemically inert⁶⁴, so it doesn’t react with other metals during electroplating.

This metal is a highly durable option with significant benefits, but its price is subject to considerable fluctuations⁶⁵, making it expensive to use. At times, rhodium can be more costly than gold or silver.

Copper Plating

Copper has one of the highest electrical conductivity⁶⁶ rates of any metal. It is highly cost-effective⁶⁷, malleable and has excellent adhesion properties, making it a perfect electroplating option. However, copper has some properties that result in certain limitations. It’s an active metal prone to corrosion⁶⁸, so it works best as an underplate or in dry, stable environments.

Platinum Plating

Platinum is a precious metal that offers durability and longevity⁶⁹. It’s conductive and corrosion-resistant and does not tarnish⁷⁰, making it an excellent choice for applications that require protection from the elements or extreme heat. It’s highly durable and wear-resistant — you can increase the thickness to add longevity and bulk components. It’s also used as an intermediary layer⁷¹ in some applications to allow for better adhesion.

Ruthenium Plating

Ruthenium is commonly used to manufacture data storage products⁷², such as microchips and read elements for semiconductors. It’s often alloyed with precious metals such as platinum and palladium to harden them for use⁷³ in wear-resistant electrical contacts, as the process enables a thinner coating.

It’s a highly heat-resistant and durable option with a chemically inert surface⁷⁴. Its long-lasting nature makes ruthenium a popular choice for surface coatings, as it doesn’t wear off or tarnish quickly.

Electroplate Connectors in Electrical Components With SPC

Electroplating is a critical part of manufacturing electrical components. With many plating options for your contacts and connectors, the best choice of materials depends entirely on your budget and manufacturing needs. Improving the quality of your manufacturing processes is essential to ensure you elevate your competitive position in the marketplace.

You can rely on SPC to walk you through⁷⁵ which electroplating materials and processes best suit your unique requirements. Since 1925, we have developed decades of metal finishing experience. We have a proven track record of plating for electronics and serve organizations across many industries. We’ve also served as consultants for other plating companies. Whether you need to consult on a specific project or overhaul your manufacturing processes, we’re here to help.

We have refined our electroplating processes over the years to improve the quality of your manufacturing processes and help ensure you can pass on that quality to customers. Request a no-obligation quote today⁷⁶, or contact us for more information on how SPC can help you. You can also subscribe to our free e-newsletter and stay ahead of the latest electronic plating and metal finishing trends.

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SPC Contact Information:

P.O. Box 157 3315 Connelly Rd. Emigsville, PA 17318

Phone: 717.767.6702

Plating Precious Metals On Refractory Metals in Electrical Connectors

Why Do We Plate Connectors in Electrical Components?

The Benefits of Electroplating for Electronic Contacts and Connectors

Improved Corrosion Resistance

Enhanced Electrical Conductivity

Low Contact Resistance

Improved Solderability

Increased Protection From Wear and Tear

Enhanced Electroplating Adhesion

Optimized Compatibility

Improved Coating Application

Types of Contact Plating for Connectors

Nickel Plating

Gold Plating

Silver Plating

Tin Plating

Palladium Plating

Palladium Nickel Plating

Rhodium Plating

Copper Plating

Platinum Plating

Ruthenium Plating

Electroplate Connectors in Electrical Components With SPC

Make SPC your source for all of your industrial plating and metal finishing needs

SPC Contact Information: