Gold vs. Silver Connectors or Contacts: What's the Difference?

Gold and silver are the two most commonly used precious metals for connectors and contacts across various industries. While each has advantages, these two popular finishes also have disadvantages and differences. Here are some of the key differences between Gold Plated Contacts and Silver Plated Contacts.
 

Global industrial demand, political and economic uncertainty, and currency devaluation are driving up gold prices. Many countries and people turn to gold during times of economic uncertainty because of its globally recognized value as a currency alternative. However, with the growth of the Internet of Things, gold is now sought after for more industrial reasons than simply as an investment or decorative jewelry: it is truly an essential metal in the production of modern electrical and electronic equipment.

Rising gold prices can significantly impact the manufacture of Gold Plating Contacts, especially for applications utilizing heavy gold deposits. While no other material can match all of gold's properties, silver offers many similar characteristics at a significantly lower price. Contacts Silver Plated can be plated heavier, at a lower cost, and the deposits produce many similar properties. However, the formation of sulfides, or silver tarnish, is a limiting factor for silver in applications that are particularly sensitive to increased contact resistance.

Silver does not form oxides or compounds with oxygen under normal conditions; however, Silver Plated Contacts do form various sulfur compounds, such as silver sulfide. Although silver sulfide compounds are relatively conductive, they do increase the contact resistance of the silver plating beyond that of pure silver alone. In many switching applications, any silver tarnish is effectively wiped off the surface within the sliding contact area. However, in static applications, silver sulfide or tarnish can increase contact resistance enough to alter the signal path in very low-voltage applications.

There are various anti-tarnish inhibitors, such as Enthone's Evabrite or Technic's Tarniban; however, all of these anti-tarnish compounds add an organic or metallic film to the surface, altering the properties of the silver electrodeposit from those of pure silver.

Compared to silver, Au Plated Contacts do not form sulfides or tarnish under any normal conditions. This makes gold a more viable option for low-voltage signal transmission applications, where even small changes in contact resistance can impact product performance. Critical applications, such as life-safety sensors or autonomous vehicle applications, require extremely reliable, real-time signal transmission, which only Gold Plated Contacts can provide.

Silver is more conductive than gold. However, gold's ability to form no resistive compounds makes it an ideal choice for milliamp data applications. It is also a good choice for low-voltage applications and corrosive conditions. Silver, on the other hand, offers excellent thermal and electrical conductivity and can be cost-effectively plated to higher thicknesses, making Ag Plated Contacts a preferred material for high-voltage and high-current power transmission applications.

While gold possesses many qualities that make it suitable for electronic components, there are several key properties to consider when specifying Gold Plating Contacts for connector or contact applications. When specifying Au Plated Contacts for a new application, consider the following key factors:

Gold Plating Services - Ensuring Proper Plating Thickness

When specifying Gold Plated Contacts, it is important to specify sufficient gold thickness to ensure proper functionality without excessive gold. The following table provides some basic guidelines for the appropriate Gold Plating Contacts thickness for most connectors and contacts.

As a general rule, functional gold starts at approximately 0.25 microns or 0.00001 inches and increases to 2.5 microns or 0.0001 inches per side. Using duplex gold, or two layers of soft-then-hard gold, provides more efficient gold barrier deposition per mil of thickness compared to using a single layer alone. This is critical in applications such as medical equipment, including magnetic resonance imaging (MRI) scanners.