We produce our WCAg40 switching contacts according to international standard ASTM B 663-94. They have a silver content of 40% by weight.
- WCAg40 (tungsten carbide 60% by weight, silver 40% by weight)
Contact materials for use in vacuum chambers
We offer low-gas contact materials for use in vacuum chambers. Our switching contacts made of tungsten carbide-silver (WCAg), tungsten-copper (WCu), and tungsten carbide-copper (WCCu) reliably switch high short-circuit currents in the range of 7.2 – 24 kV in vacuum contactors, closed-circuit systems, and reclosers and can withstand over a million switching cycles.
Your advantages at a glance:
High resistance to arc erosion
Excellent electrical conductivity
Excellent resistance against contact welding
Very low chopping current
The right switching contact for every application
We supply our WCu switching contacts in VFG (Vacuum Fine Grained) quality. This means that they are ultrapure and have an excellent electrical conductivity. Depending on the requirements, we have various VFG materials in our range with two different copper contents:
- VFG10 (tungsten 90% by weight, copper 10% by weight)
- VFG20 (tungsten 80% by weight, copper 20% by weight)
Our switching contact made of WCCu30 is a cost-effective alternative to WCAg and is also manufactured from low-gas raw materials for use in a vacuum.
- WCCu30 (tungsten carbide 70% by weight, copper 30% by weight)
Do you have any questions regarding choosing the right material or our switching contacts? We would be happy to advise you.
Typical material properties for our contact materials for use in a vacuum
WCAg40 |
VFG10 |
VFG20 |
WCCu30 |
|
WC (% by weight) |
60 |
0 |
0 |
0 |
Ag (% by weight) |
40 |
0 |
0 |
0 |
W (% by weight) |
0 |
90 |
80 |
0 |
Cu (% by weight) |
0 |
10 |
20 |
30 |
Density (g/cm3) |
12.6 |
16.5 |
15.2 |
12.2 |
Electrical conductivity (m/ohmmm2) |
20 |
22 |
25 |
15 |
Hardness HV30 |
170 |
220 |
210 |
230 |
In order to be able to offer you the ideal combination of different material properties, we produce our composites using powder metallurgy processes. The most important steps: we mix the base materials, then press and sinter the material. This is the most cost-effective way to ensure our contact materials have the necessary electrical and mechanical properties. Our manufacturing process enables us to achieve a very high material density of over 97%.
A comparison of various contact materials
In the graph below you can see the chopping current of various contact materials tested in a 20 kA/24 kV vacuum contactor at a maximum current of 630 amperes.
- Source: F. Heitzinger et al., 15th ISDEIV, Darmstadt, 1992
Other products for energy technology
Would you like to know more about our contact materials for medium voltage? Then please visit our product pages for switching contacts made of tungsten-copper and copper-chromium: