The Benefits of Gold Plating on Connectors

By Contributed Article | February 04, 2025

Gold plating offers unparalleled durability and corrosion resistance to interconnects. Learn how gold — or a cost-effective alternative — can impact connector selection.

Gold plating has a long history of utility in the connector industry due to its highly effective combination of durability, corrosion resistance, ductility, and electrical conductivity. The material offers stability under a wide range of temperatures and provides atomically clean surfaces, making gold-plated connectors an ideal selection for aerospace, military, telecommunications, industrial, and other applications that require high reliability performance under harsh conditions, including corrosive environments where high humidity, moisture, or chemicals are present. Plating conveys the benefits of gold without the expense of solid contacts.

Gold plating on PCB connectors provides durability and corrosion resistance, ensuring reduced maintenance needs and extends a connector’s lifespan, especially in harsh environments.

Gold’s corrosion resistance makes it an essential factor in the design of harsh environments electronics Gold is one of the least reactive metals and does not react with oxygen or moisture, making it highly resistant to oxidation under environmental stressors. This ensures that it won’t corrode in extreme environments.

Corrosion reduces the electrical reliability of connectors. Rust, base metal bleed-through, or tarnish form an oxide layer that impairs connector reliability. A tarnished connector may be perceived as unreliable or damaged, leading to concerns about its performance.

Conductivity under stress

Gold is the third most electrically conductive element, following copper and silver, due to its electron configuration, but gold plating is often preferred over copper and silver because of its durability and corrosion-resistant properties. For connectors, it is superior for long-term use in high-stress environments, such as military and aerospace applications. Gold plating provides superior electrical and mechanical performance in applications that are frequently under stress, including applications that require frequent mating cycles, such as testing and instrumentation. Gold’s durability and longevity make the material ideal for connectors that endure repeated mating cycles.

SV Microwave offers gold plating on RF connectors including blind-mate connectors and those with center contacts. Any connector featuring a socket is also gold-plated, since its base (typically heat-treated beryllium copper) is prone to corrosion if unprotected.

Specifying gold plating

The thickness and hardness of the gold layer on connectors can affect performance and durability. Different gold thicknesses and hardness levels depend on the specific application’s connector requirements. Thick gold plating, typically 1.27 microns or above, provides superior corrosion resistance. This method is favored in applications that face environmental stressors or high mating cycles. Thin gold plating, around 0.25-0.76 microns, is sufficient for connectors used in low-stress environments. While a cost-effective application of gold material, thin plating can be porous, which may increase the chances of corrosion. Nickel underplating adds an extra layer of protection while using less gold material.

Gold hardness, which varies based on purity levels, affects how well the gold performs under different conditions. With purity levels typically ranging from 99% to 99.9%, hard gold —containing more impurities — is particularly suited for connectors that must withstand sliding contact or high mating cycles, as its toughness helps prevent degradation over time.

Another issue that can compromise performance is gold embrittlement during the solder cycle. Excess gold in a solder joint can create a gold-tin compound known as AuSn3. Under a microscope, this element displays as gold striations. Too many of these striations and the solder join become brittle and can even break under mechanical stress like shock and vibration.

SV Microwave offers a line of Pre-Tinned Connectors designed to remove gold from solderable areas, preventing embrittlement. SV also provides degolding services for cable ferrules, tailored to specific applications.

Alternatives to gold

Several alternatives to gold plating exist, including nickel, silver, and passivated stainless steel. These materials offer cost-effective solutions while providing varying degrees of corrosion resistance.

Passivated stainless steel

The passivation process involves treating steel with nitric or citric acid to remove free iron from the surface. This treatment eliminates impurities that cause rust and forms a protective oxide layer, making the stainless steel more corrosion-resistant. This process is often utilized for threaded connectors because of their stainless-steel bodies.

Passivated stainless steel is commonly used for SV’s threaded connectors and offers an excellent alternative to gold plating.

Silver

Silver is more conductive than gold and is a suitable gold alternative for some applications. However, gold offers superior corrosion resistance, which makes it the preferred choice for harsh environment applications.

Nickel

Nickel plating offers a more cost-effective solution than gold. While it provides a degree of corrosion resistance, it does not match gold’s long-term conductivity.

While these alternatives provide certain advantages, none can match the reliability, durability, and corrosion resistance of gold plating on connectors, making it the best option for critical applications. Understanding the role of plating materials is critical when designing for high-stress applications or seeking a cost-effective yet reliable solution.

Visit SV Microwave to find the best solution for your application or contact an SV engineer to learn more at [email protected].