Plating on Copper Base Materials

Plating onto Copper

Copper is a soft, ductile metal that's used in numerous industrial processes and applications. Copper's excellent thermal properties and high electrical conductivity make it a top choice for manufacturing products such as wire and cable, integrated circuits and circuit boards, conductors, electric motors, building materials, piping and many other items.

Copper is available in abundant quantities, and it's also one of the few metals found in a usable form — it does not need to be extracted from ores. These characteristics make the use of copper in manufacturing a highly cost-effective process.

Alloying Copper With Other Metals

Pure copper (UNS C11000 — 99.9% Cu purity) is often used for electronic manufacturing applications. However, producing copper alloys by combining it with other metals is a common practice in other industries. Creating an alloy with one or more metals will enhance the performance of the copper — as well as the other materials — and make it better suited for a wide variety of industrial processes. It is also easier to produce alloys with copper than most metal materials. Examples of the hundreds of copper alloys include:

• Brass: Combining copper with zinc produces brass, a yellowish material known for its resemblance to gold. While brass is often used for decorative purposes, altering the amount of copper and zinc will introduce valuable manufacturing properties such as hardness, electrical and thermal conductivity and corrosion resistance.
• Copper-nickel: Adding nickel to copper increases its strength and enhances its resistance to corrosion. Common industrial applications include marine and biofouling.
• Beryllium-copper: Beryllium increases the hardness of copper. A beryllium-copper alloy exhibits mechanical properties similar to high-strength steels. Beryllium also does not form oxides until reaching extremely high temperatures.
• Bronze: Bronze consists of a combination of copper and other metals such as tin, aluminum and silicon. Phosphor bronze is a copper-tin alloy known for its strength, good protection against wear and excellent corrosion resistance.
• Cupronickel: Cupronickel is a copper-nickel alloy that also contains metals such as manganese and iron for additional strength. Cupronickel provides superior resistance to corrosion caused by seawater, making it a popular choice for marine applications.

Plating on Copper Alloys

While alloying copper with other metals provides many beneficial properties for manufacturing purposes, it is sometimes necessary to enhance these characteristics and/or introduce new properties. There are several time-tested metal finishing techniques that can achieve these objectives:

• Electroplating: Electroplating deposits an additional coating onto the surface of the copper alloy substrate. The workpiece is immersed in an electrolyte solution containing dissolved ions of another metal. The introduction of a DC current stimulates a reaction that coats the substrate with the metal via electrodeposition.
• Electroless plating: Electroless plating also coats the copper alloy with another metal material. However, this technique does not require an electrical current. Instead, deposition occurs via an autocatalytic react that occurs between the workpiece and the liquid plating solution.

Processes for Plating Onto Copper and Copper Alloys

Electroplating copper and copper alloys is a common practice when manufacturing parts for industries such as aerospace, automotive, defense and electronics. Typical metals used for copper plating include:

• Tin: A coating of tin will increase the operating temperature of a copper substrate and improve its solderability. Tin is also less expensive than many other metals, making it a suitable copper electroplating process for cost-conscious companies. Tin plating should only be used on base materials that are not exposed to high-temp processing after the application of the coating.
• Silver: The silver plating of copper will increase the operating temperature of copper alloy conductors. Silver also provides superior solderability and excellent electrical conductivity. When used for plating a copper conductor, silver will enhance the high-frequency transmission capabilities of the wire.
• Nickel: An electroplated nickel coating will increase the copper substrate's corrosion resistance and operating temperature. However, because of nickel's hardness, nickel-plated conductors tend to exhibit greater crimp termination variability than other metal materials.
• Multiple coating layers: Some copper electroplating processes entail a sequential deposition of multiple metals onto the substrate. This will reduce the reaction between the base metal and the surface while still maintaining the beneficial properties of the surface plating.
• Electroless nickel: Electroless nickel is often applied to copper electronic components as a final step in the manufacturing process. This involves the application of electroless nickel with immersion gold to copper traces.

SPC Offers an Array of Copper Electroplating Services

No matter what type of copper alloy you use in your manufacturing processes, SPC can implement a high-quality copper plating process that will improve the performance, durability and appearance of your workpieces. With more than 90 years of metal finishing experience, you can count on us to recommend the right process for your applications. Contact us for a free copper plating quote!

Additional Resources:

• Copper Plating Troubleshooting Tips
• Electroplating Electronic Components Surface Preparation