King Pin | Bead Electronics Blog

Plating for Electronic Connector Pins and Contacts

Posted by bead electronics on Nov 20, 2020 11:41:43 AM


plating-for-pins-feature

Choosing the right material for contact plating is critical for ensuring durability, conductivity, and resistance to corrosion to meet your connector needs. We have created an overview of common plating options for electronic connector pins and contacts. Read below to learn about various coating metals and their various applications. 


 

GOLD

Most noble metal and is very resistant to corrosion. Excellent for low voltage and current applications. The coefficient of friction is low allowing for low insertion and withdrawal forces. Because of low wear, mating cycles can be high. High reliability and excellent wear properties allow for a long life in harsh environments.

Typical plating thickness: 10-50 u"

Common Applications:

gold-plating-icon
  • Military/Aerospace
  • Automotive/Transportation
  • Healthcare/Medical
  • Communications
  • Connectors
  • Instrumentation/Sensors

 

SILVER

Is also a noble metal and has the highest electrical and thermal conductivity of all metals. It also has very low contact resistance. Silver does tarnish, but it is mitigated when contacts are mated and unmated. It is used mainly for high-current contacts.

Typical plating thickness: 100-300 u”

Common Applications:

silver-plating-icon
  • Military/Aerospace
  • Automotive/Transportation
  • Healthcare/Medical
  • Communications
  • Lighting
  • Connectors
  • Instrumentation/Sensors

 

PALLADIUM

Is also a noble metal and has the highest electrical and thermal conductivity of all metals. It also has very low contact resistance. Silver does tarnish, but it is mitigated when contacts are mated and unmated. It is used mainly for high-current contacts.

Typical plating thickness: 10-30 u”

Common Applications:

palladium-plating-icon
  • Military/Aerospace
  • Automotive/Transportation
  • Healthcare/Medical
  • Communications
  • Connectors
  • Instrumentation/Sensors

 

PALLADIUM NICKEL   

The alloy has all of the advantages of palladium without the “fretting” issues or “brown powder” effect. Compared to palladium, palladium-nickel is less prone to cracking, is more resistant to heat and galvanic corrosion as well as allowing for reduced porosity and excellent solderability. PdNi followed by a gold flash offers more advantages, including acting as a solid lubricant, better corrosion protection and a higher number of mating cycles. 

Typical plating thickness: 10-30 u”

Common Applications:

palladium-plating-iconnickel-plating-icon
  • Military/Aerospace
  • Automotive/Transportation
  • Healthcare/Medical
  • Communications
  • Connectors
  • Instrumentation/Sensors

 

RHODIUM 

This plating has a high hardness (800 to 1000 Hv) and superior corrosion resistance. It is ideal for parts that require long-term stable contact resistance. It is used for switch contacts, test probe parts and some connectors. Heat resistance is very good, and it does not oxidize in air at 500 degrees C or lower.

Typical plating thickness: 20 u”

Common Applications:

rhodium-plating-icon
  • Military/Aerospace
  • Connectors
  • Instrumentation/Sensors

 

TIN

Unlike the above metals, tin is not in the noble category. It quickly develops an oxide layer when exposed to air. A contact system plated with tin requires greater forces and a longer wipe area to break through the oxide film. The higher coefficient of friction causes higher insertion and withdrawal forces and more wear, which limits mating cycles to less than 50. Whisker growth is a concern with close contact spacing. Tin offers excellent solderability and low cost. It is a very good finish for press-fit contacts.

Typical plating thickness: 100-300 u”

Common Applications:

tin-plating-icon
  • Common - many applications

 

TIN LEAD      

This finish has many similar properties as tin, without the whisker-growth. Its melting point is altered by lead content, but overall it is relatively low. Contact resistance and corrosion resistance are similar to tin, but solderability is improved. The finish provides lubricity, excellent conductivity and good shelf-life. Color ranges from matte gray to a bright, almost chrome-like appearance.

Typical plating thickness: 100-300 u”

Common Applications:

tin-plating-iconlead-plating-icon
  • Military/Aerospace
  • Automotive/Transportation
  • Connectors

 

WHITE BRONZE     

An alloy of copper, tin and zinc, this finish has gained popularity with RF connectors for a number of reasons. Because white bronze is non-magnetic, intermodulation concerns are diminished. Porosity is low as well as RF losses. Corrosion resistance is high and there is no discoloration, like silver. Compared to nickel, a common finish for connectors, health safety is improved.

Typical plating thickness: 50-200 u”

Common Applications:

copper-plating-icontin-plating-iconzinc-plating-icon

  • Military/Aerospace
  • Healthcare/Medical
  • Connectors

 

NICKEL   

Nickel plating is widely used in electronic components, such as connectors, contacts and integrated circuits. It is in the passive metal group and is often used for corrosion protection. It is very hard, durable and has high electrical conductivity. Nickel does form a hard oxide, but it is stable and does not grow continuously at the expense of the coating layer. For most battery contact applications voltages are high and current is driven through the oxide film. Nickel is commonly used as a diffusion barrier, preventing the migration of base material atoms to the top coating which is often gold. Because it is magnetic, it is not suitable for some RF type connectors.

Typical plating thickness: flash – 300 u”

Common Applications:

nickel-plating-icon
  • Common - many applications

 

ELECTROLESS NICKEL

This nickel alloy coating is deposited by chemical reduction, meaning without electrical current as with nickel electroplating. Most electroless nickel deposits are alloyed with phosphorus in the range of 2-14%. The higher the phosphorus content the greater the corrosion resistance, but the hardness decreases. Compared to electrolytic nickel, electroless provides a more uniform thickness over the substrate, even in holes and ID’s. It is also less prone to porosity.

Typical plating thickness: 50-300 u”

Common Applications:

nickel-plating-iconcopper-plating-icon
  • Military/Aerospace
  • Automotive/Transportation
  • Healthcare/Medical
  • Communications
  • Connectors
  • Instrumentation/Sensors

 

COPPER

Copper is a very electrically conductive metal, second only to silver. Unfortunately, it is prone to corrosion, which would impact conductivity. Using a protective layer could help avoid corrosion and most electronic connectors have nickel, tin or one of the noble metals applied after copper. Additionally, copper has excellent leveling and uniform deposition properties, which can help build up undersized parts.

Typical plating thickness: flash – 200 u”

Common Applications:

copper-plating-icon
  • Primarily an underplate

 

About Bead Electronics

Bead Electronics, is a global manufacturer of electronic connector pins and has been manufacturing in Connecticut for over 100 years. The award-winning company carries over 500 patents and is best known for inventing its manufacturing process called swaging. This process is a high-speed, virtually scrap-less, cold-forming process capable of producing a wide size range of metal electronic components that are consistent and cost-effective. The family-owned business is led by its fifth generation. Click here to speak to a connector pin specialist today.

You may also be interested in:New call-to-action

Topics: Electronic Pins, Contact Pins, Custom Contact Pins, Custom Connectors, Bead Electronics