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. |