Features and Typical Application of Relay Contact Material

- Dec 25, 2019-

Features and Typical Application of Relay Contact Material

 

For the same relay, different contact materials are suitable for different load types or ranges, as shown in the table below:


Material

Features

Typical application

AgNi+ Au

-The gold coating has good corrosion resistance in   air;

-Compared with other materials, it has smaller   contact resistance and better consistency under small load;

-Good conductivity and thermal conductivity;

-Small load: there is almost no corrosion on the gold   coating, from 10mW (5V, 2mA) to 1.5W (24V, 62.5mA) (resistive load)

-Medium load: after several actions, the gold coating   is eroded and the matrix Agni plays a major role, from 2.4W (24V, 100mA) to   60W (30V, 2A) (resistive load)

Note: when switching off the low load, the typical   value is 1mW (0.1v-1mA) (for example, in the test instrument), it is   recommended to use two pairs of parallel contacts.

AgPd

-It has good corrosion resistance and vulcanization   resistance at room temperature;

-The contact resistance is small and the consistency   is good;

-It's expensive.

Ditto

AgNi

-Standard material for most relay contacts

-Good conductivity and thermal conductivity;

-High ablation resistance

-Medium resistance to welding

-Sulfide film is easy to form in sulfide environment

-Resistive load and less inductive load

-General rated current less than 12a

-General surge current is less than 25A

AgCdO

High AC load

-Good conductivity and thermal conductivity;

-High ablation resistance

-Good adhesion resistance

-Sulfide film is easy to form in sulfide environment

-Resistive load, motor load and inductive load

-General rated current less than 30A

-General surge current is less than 50A

AgSnO2

-Excellent adhesion resistance

-Less material transfer under DC load than above

-Sulfide film is easy to form in sulfide environment

-Lamp load, inductive load and capacitive load

-Very large surge current (up to 120A) load

AgSnO2 contains other oxides

Ditto

-Lamp load, inductive load and capacitive load

-Very large surge current (up to 120a) load

-With different oxides, the applicable load will be   different

Note:

1.  The maximum current value specified in the   manual must be considered for each relay.

2.  When general conditions permit, it is better   to conduct test confirmation in actual use.

3.  The gold coating of contact has better   performance for medium and small load. However, in the case of large load, it   is usually only used to maintain the initial contact performance of the   contacts before the relay is used.