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Tungsten electrodes for discharge lamps

Tungsten electrodes for discharge lamps

The core components of discharge lamps generally consist of a cathode, an anode, and the supporting bars. Depending on the type of lamp, the electrodes are either complex molded parts or simple pins. When voltage is applied to the anode and cathode, a bright arc is produced. The tips of the electrodes must be able to withstand temperatures of 1,800 to 3,400°C during lamp operation. They transfer the waste heat to the electrode body and the supporting bars.

Your advantages at a glance:

  • High temperature stability up to 3,400°C

  • Excellent creep resistance

  • Reduced electron work function thanks to oxide doping

  • High thermal conductivity thanks to high core densities

  • Excellent workability

  • Good breaking strength

Download our product specifications:

W rod specification

Tungsten – the ideal material for your application

Tungsten electrodes

Tungsten is the only metal that satisfies the stringent physical and mechanical requirements. Tungsten has the highest melting point of all metals, a low vapor pressure, a low thermal expansion, and good thermal conductivity.
Our special manufacturing processes prepare the tungsten perfectly for use as a cathode, anode, or supporting bar. We use special alloying additions to improve high-temperature dimensional stability, electron emission capacity, and mechanical workability in order to satisfy the specific requirements for the lamp.

Tungsten cathodes

We provide tungsten doped with aluminum-potassium silicate (AKS) or lanthanum oxide for cathodes. We also provide WLZ: a tungsten material doped with lanthanum and zirconium oxide. The oxide-doped alloys are the non-radioactive alternative to thoriated materials. We also provide porous tungsten or tungsten-rhenium cathode bodies for infiltration with barium oxide, for example.

Tungsten anodes

Anodes must be able to withstand the highest thermal loads. We provide special potassium-doped tungsten materials for this purpose.

  • WVM = 30 - 70 µg/g potassium doping, Dm 2-13 mm
  • WVMW = 15 - 40 µg/g potassium doping, Dm 13 mm + larger
  • S-WVMW = 15 - 40 µg/g potassium doping, Dm 35 mm + larger

These materials have a particularly good high-temperature stability and are characterized by their excellent creep resistance and burn-off behavior.
For applications with a particularly high load, we provide special coatings that increase the emissivity and thereby improve the thermal radiation.

Tungsten supporting bars

Supporting bars are primarily responsible for supporting the cathodes and anodes. While the lamp is being transported, they are subjected to high mechanical impact loads. In order for the lamp to work, the electrical and thermal conductivity are also essential. We provide the tungsten alloys WVM and WL-S as the ideal solution for supporting bars. Both alloys are particularly break-proof following high-temperature treatment, during the production of the lamp bulb.

Short arc lamp with a tungsten electrode:

Short arc lamp with a tungsten electrode

  

Our materials for tungsten electrodes at a glance: 

Material

Dimensional stability

Electron emission

Diameter [mm]

Delivery form

Typical application

WLZ

high

high

6.0 - 25.0

Rods and electrodes ready for installation

Cathode

WL10

low

high

1.2 - 80

Wire, rods, and electrodes ready for installation

Cathode

W porous

low

high

Upon request

Blanks, ready for use for infiltration 

Cathode

WL-S

high

low

5.0 - 10.0

Wire, rods, and electrodes ready for installation

Electrodes and anodes

WVM

high

low

1.2 - 12.99

Wire, rods, and electrodes ready for installation

Electrodes and anodes

WVMW

high

high

15 - 30

Rods and electrodes ready for installation

Electrodes and anodes

S-WVMW

high

high

25 - 40

Rods and electrodes ready for installation

Electrodes and anodes

 

We'll be happy to help you select the optimum material for your application. Get in touch!