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WCAg switch contacts for medium and low voltage.

Our tungsten carbide-silver (WCAg) switch contacts are perfect for your power needs. They reliably switch short-circuit current in vacuum contactors in the 7.2 - 24 kV range, for instance, and have a life of more than a million switching cycles.

We manufacture WCAg compliant with the international standard ASTM B 663-94.

  • high arc erosion resistance
  • excellent electrical conductivity
  • outstanding contact welding resistance
  • very low chopping current
WCAg switching contacts

Our tungsten carbide-silver contact materials have a silver content between 25 and 60 wt.-%. We would be happy to advise you on the correct choice of material.

Typical properties of our WCAg contact materials:

WC [wt.-%] 6040
Ag [wt.-%]4060
O2 [ppm]8580
N2 [ppm]6070
Density [g/cm3]12.711.6
Hardness [HV30]170130
Electrical conductivity [m/Ωmm2]2235
WCAg switching contact

We use powder metallurgical techniques to manufacture our composite materials so that we can offer you the ideal combination of different material properties. The most important steps: We mix the input materials and then press and sinter the resulting material. This is the most cost-efficient way of giving our WCAg contact materials the required electrical and mechanical properties. Our manufacturing process allows us to achieve an extremely high material density in excess of 97 %.

Microstructure WCAg
Microstructure of WCAg40 at different magnifications
Microstructure WCAg

Comparison of different contact materials.

Chopping current for different contact materials

The chart shows the chopping current for different contact materials during testing in a 20kA/24 kV vacuum contactor at a maximum current of 630 A.
(Source: F. Heitzinger et al., 15th ISDEIV, Darmstadt, 1992)

Additional typical properties of different contact materials:

Material properties
Density [g/cm3]12.512.711.68.1515.2
Vickers hardness33017013080200
Electrical conductivity [m/Ωmm2]2022353218

More products for power engineering.

Are you also interested in our contact materials for high and medium voltages? You can find out more about tungsten-copper and copper-chromium here.