Cladding and electroplating are two processes for bonding dissimilar metals that have their origins in the 1800s. For this discussion, we will focus on precious metals as they relate to the electronics industry. Gold is most prominently used for electronic components thanks to its desirable qualities including corrosion resistance and excellent electrical conductivity. Due to the cost of gold, many electronic contacts and connectors have gold only where it's needed. This is achieved using selective deposit processes, primarily cladding and electroplating.
Both approaches involve applying the gold to flat strip stock that is usually a copper-based alloy. These materials typically include phosphor bronze, beryllium copper, or nickel silver. The metal can then be blanked, formed, stamped, or deep drawn.
Cladding can be done with one of two processes: inlay cladding and overlay cladding. Inlay cladding is the process usually used for electronic components because of its selectivity. For connector parts, a strip of gold is bonded to a strip of nickel which acts as a diffusion layer between the gold and base metal. The selective area of the base metal is then grooved where the gold/nickel material will be roll bonded. This process may be preferred to electroplating when thicker gold layers are required, as much as one-third of the base material thickness. Cladding also allows for the bonding of alloys not available with electroplating.
Electroplating is a viable alternative for depositing gold layers less than 100 micro-inches. Though the process is more complex and requires a selective plating cell, gold plate solution, power source and line. The desired properties of the gold deposit are the same and most selective plating shops can easily set up for processing. In general, electroplating is considered a more cost-effective option.
Both cladding and electroplating can meet most of the requirements for electronic components, but some needs are unique and require careful consideration. All factors must be carefully weighed when choosing the right process suited for the job.
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