Gold and silver are the two most commonly used precious metals for connectors and contacts in various industries. There are advantages to each, but there are also disadvantages and differences between these two popular finishes. Below are some of the key differences between gold and silver electroplating.
1. Cost - Disadvantages of Gold Plating
Global industrial demand, political and economic uncertainty, and currency devaluation are all pushing gold prices higher. Many countries and people turn to gold during times of economic instability because of its globally recognized value as a substitute for money. However, the development of the Internet of Things is the reason why gold is now being sought more industrially than just as an investment or decorative jewelry: gold is indeed an essential metal in the production of modern electrical and electronic equipment.
Rising gold prices can significantly impact the manufacture of gold-plated components, especially for applications using heavy gold deposits. While no other material can match all the properties of gold, silver has many similar properties at a significantly lower price. Silver can be plated heavier and less expensive, and the deposits produce many similar properties. However, the formation of sulfide, or silver tarnish, is one of the limiting factors for silver in applications that are very sensitive to increased contact resistance.
2. Silver rust - the disadvantage of silver plating
Silver does not form oxides or compounds with oxygen under normal conditions; however, silver plating does form various sulfur compounds, such as silver sulfide. Although silver sulfide compounds are relatively conductive, they do increase the contact resistance of the silver coating over the contact resistance of pure silver alone. In many switch applications, any silver rust is effectively wiped away from surfaces within the sliding contact area. However, in static applications, silver sulfide or tarnish can increase contact resistance enough to alter the signal path for very low voltage applications.
There are various anti-tarnish inhibitors, such as Enthone's Evabrite product, or Technic's Tarniban product; however, all of these anti-tarnish compounds add an organic or metallic film to the surface that alters the properties of the silver electrodeposit, making it Unlike sterling silver.
In contrast to silver, gold does not form sulfides or tarnish under any normal conditions. This makes gold a more viable option for low-voltage signaling applications where small changes in contact resistance can affect product performance. Critical applications such as life safety sensors or autonomous vehicle applications require extremely reliable real-time signal transmission, which only gold plating can provide.
3. Electrical conductivity - silver and gold electroplating
Silver is more conductive than gold. However, gold's ability to not form any resistive compounds makes it ideal for milliamp data applications. It is also a good choice for low pressure applications and corrosive conditions. Silver, on the other hand, has excellent thermal and electrical conductivity and can be cost-effectively plated to higher thicknesses, making it the material of choice or for high voltage and high current power transmission applications.
