Connectors

Contact (Terminal) - Connector Trivia vol.4 -

# Trivia

An overview of metal contacts (or terminals) and their materials.

What is a Contact and its Materials?

Contacts are metal parts that allow connectors to have contact and energizing functions.
A metal plate is pressed using a mold, and then sheared and bent to form a shape. The parts are then plated to complete the contact.

It is like cutting out the dough of a stretched cookie and pour chocolate over it.

Types of Metal Used in Contacts

Copper alloy with low electrical resistivity are used as the metal material in contacts.
Despite its good electrical characteristics, copper has mechanical weaknesses, such as very low tensile strength and softness, so we use a copper alloy with excellent spring characteristics for contacts where contact stability is important.
Use the following materials according to the specifications required for the connector.

Metal Material	Description
Phosphor bronze	A copper alloy made by blending copper (Cu) with phosphorus (P) and tin (Sn), which has excellent mechanical characteristics and is a standard material. It is also easy to handle.
Brass	A copper alloy containing copper (Cu) and zinc (Zn). It is a cheap material that is widely used in consumer and automotive applications.
Corson copper	A copper alloy made of copper (Cu) blended with nickel (Ni) and silicon (Si), which is widely used in the automotive market as a high-conductivity, high-heat-resistant material.
Beryllium copper	Used as a high-strength copper alloy material that contains several percent of beryllium (Be) in copper (Cu), but the use of beryllium is restricted in some cases due to its toxicity.

Types of Plating Used for Contacts

The contact area is plated to prevent oxidation and corrosion of the contact area, to retain electrical characteristics, and to make it easier for customers to solder the connection area.

Keywords

What is plating?
The application of a thin film of metal to the surface of a metal or non-metal material.

plating

Use the following materials according to the specifications required for the connector.

Plating material	Surface / Undercoat	Description
Tin (Sn)	Surface	Electrical characteristics are inferior to those of gold or silver, but still good. Less corrosion-resistant but relatively inexpensive.
Gold (Au)		Excellent electrical characteristics and corrosion resistance but is expensive.
Silver (Ag)		Excellent electrical properties but poor corrosion resistance. Expensive compared to tin but inexpensive compared to gold.
Palladium (Pd)	Surface and undercoat	Hard and excellent corrosion resistance. It is used to reduce the amount of gold used.
Nickel (Ni)	Undercoat	Hard and good adhision.
Copper (Cu)	Undercoat	Excellent adhesion. Nickel is now the mainstream.

Click Here for Inquiries

Comprehension Test

Q. Complete the following paragraph by filling in (a) to (f) using the keywords below.

　　(1) Gold 　(2) Silver 　(3) Tin 　(4) Nickel 　(5) Adhesion 　(6) Corrosion resistance

Tin (Sn): Electrical characteristics are inferior to those of gold or ( a ) but good. Less corrosion-resistant but relatively inexpensive.
Gold (Au): Excellent electrical characteristics and corrosion resistance but is expensive.
Silver (Ag): Excellent electrical characteristics but poor corrosion resistance. Expensive compared to ( b ), but inexpensive compared to gold.
Palladium (Pd): Hard and has excellent ( c ) characteristics. Used to reduce the amount of ( d ).
Nickel (Ni): Hard and excellent in ( e ) characteristics.
Copper (Cu): Excellent adhesion. Today, ( f ) is the mainstream.

Answer (Click to Check)