Alloy Formulations

• Good arc-extinguishing properties
• Low arc erosion
• Low and stable contact resistance during the lifetime of the device
• Low temperature rise
• anti-welding properties

Pure Silver (min. 99.9% of Silver) has the highest thermal and electrical conductivities among all metals, is very resistant against oxidation and has excellent formability. However, its low mechanical strength, high erosion rate, high tendency of welding and high tendency of tarnishing in contact with sulphur limits its application.

Typical uses of Pure Silver are push-buttons, relays, appliance and control switches for very low currents.

• For improving some properties of the Pure Silver, like mechanical strength and erosion resistance, other elements like Copper and Nickel are added forming Silver Alloys. However, the addition of elements in the pure silver worse the contact resistance, the anti-oxidation properties and the formability of the contact material.

• When 0.15% of Nickel is added during the melting process, very fine and dispersed nickel particles are precipitate during the solidification, decreasing the grain size of the Ag grains, producing what is called Fine Grain Silver (Ag/Ni 99.85/0.15). The main advantages of Fine Grain Silver are the improved mechanical properties, if compared with pure silver, without a significant worsening of the best properties of the pure silver, which make Fine Grain Silver a better choice than Pure Silver in most applications.

• Since Copper has a much better solubility in Silver than Nickel, adding Copper is a good alternative for increasing the mechanical properties of Pure Silver even more. The addition of Copper also improves the arc erosion resistance and anti-welding properties of the contacts, however the increase of copper content will have negative influence in other characteristics like contact resistance and resistance against oxidation.

• Typical uses of Silver Alloys are switches, relays and wire devices up to 20A.

• Our Pure Silver and Silver-Alloys contacts are normally produced in the shape of wires, strips, rivets and contact tips and the typical properties of these materials are listed in the table below:

• This table shows typical material properties. The real contact properties will depend on the shape and production route.

If you have different requirements, AE has a team of materials engineers, specialized in the development of contact materials, that will study your necessities.

Silver-Nickel is a very popular contact material and is used all around the world. As there is no significant solubility between the two elements, this material is produced by the powder metallurgy (PM) route. For Nickel contents up to 30%, the preferable PM route is extrusion of Ag/Ni into wires and strips and for Nickel content above 30%, the preferable PM route is Press-Sinter-Repress (PSR).

• Silver-Nickel contacts have good mechanical strength, good welding resistance, low and almost constant contact resistance throughout the life of contact, high arc resistance, good arc moving and extinguishing properties. In addition to that, one of the major reasons of the popularity of this contact material is the fact that it can be directly welded onto copper carriers from wire, without the necessity of adding brazing alloy, bringing significant cost advantages for automation of welding lines. However, this advantage limits the application of Silver-Nickel materials to currents up to 100A, when not paired with other contact materials as Silver-Graphite.
• Typical uses of Silver-Nickel contacts are relays, switches, wiring devices, thermostats, contactors circuit breakers, motor protective circuit breakers.
• Our Silver-Nickel contacts are normally produced in the shape of wires, strips, rivets and contact tips and the typical properties of these materials are listed in the table below:This table shows typical material properties. The real contact properties will depend on the shape and production route.

• If you have different requirements, AE has a team of materials engineers, specialized in the development of contact materials, that will study your necessities.

• Good arc-extinguishing properties
• Very low arc erosion
• Low and stable contact resistance during the lifetime of the device
• Low material transfer during DC load
• Good temperature rise
• Excellent anti-welding properties

Silver-Tin Oxide can be produced by two routes, powder metallurgy (PM) and internal oxidation (IO), which bifurcate into several other different process methods. In both cases, the use of dopants aids the electrical performance and formability of the materials. HP domains most of the process methods and the best choice will depend on the interaction between the contact material and the customer device.

Typical applications of Ag/SnO2 are switches, relays (including automotive relays), contactors.

Our Silver-Tin Oxide contacts are normally produced in the shape of wires, strips, rivets and contact tips and the typical properties of this material are listed in the table below:

• Very low arc erosion
• Low and stable contact resistance during the lifetime of the device
• Excellent anti-welding properties

Our Silver-Zinc Oxide contacts can be produced in the shape of wires, strips, rivets and contact tips. The typical composition produced by HP is Ag/ZnO 91/9.

If you have different requirements, AE has a team of materials engineers, specialized in the development of contact materials, that will study your necessities.