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Glass melting electrode product range

Molybdenum glass melting electrodes

Molybdenum glass melting electrodes for electrically heated glass tanks must be able to withstand extreme thermal loads and aggressive glass melts. Our molybdenum is ideal for these difficult conditions.

Thanks to a special forging process, the glass melting electrodes we manufacture possess a particularly smooth surface. In addition, our forming processes result in a particularly coarse-grained, creep-resistant material structure coupled with optimum straightness. This ensures that our glass melting electrodes do not deform, are less prone to wear, and last longer.

Your advantages at a glance:

  • Highest purity for bubble-free application (min.
    99.97%)

  • Best electrical and thermal properties

  • Excellent creep
    resistance

  • Excellent
    corrosion resistance

  • Optimum protection against oxidation via a Sibor® coating

  • Customer-
    specific solutions as well as standard products from stock

Download our product specifications:

Mo glass melting electrode specification

Low corrosion ensures a long service life for the electrodes

Molybdenum exhibits excellent corrosion resistance with regards to most glass melts. Low material removal rates are the deciding factor for a long service life of the glass melting electrode and also have a major influence on the final quality of the glass.

  • Molybdenum corrosion data sheet

Molybdenum-zirconium dioxide glass melting electrodes

We offer glass melting electrodes made of MoZrO2 for glass production in particularly aggressive glass melts. Small quantities of zirconium dioxide (ZrO2) added to molybdenum enhance the properties of the pure material. MoZrO2 offers a particularly high level of corrosion resistance to glass melts as well as better creep resistance than pure molybdenum.

Oftentimes aggressive refining agents such as antimony oxide and arsenic oxide are used in glass melts. They harm the grain structure of pure molybdenum and lead to the rapid abrasion and breakage of the electrodes. MoZrO2 is able to withstand this aggressive environment. Even in brown and green container glass, the addition of zirconium dioxide is able to considerably reduce electrode corrosion.

Sibor® – our oxidation protection for molybdenum

Molybdenum begins to oxidize at over 400°C. Sibor® protects molybdenum from oxidation up to 1700°C (3092°F). The very hard, dense coating creates a diffusion barrier along the base material and forms an SiO2 seal against the air. Depending on the operating temperature, the material is protected against oxidation by the Sibor® layer for up to 5000 h. Using Sibor®, you can mount the electrodes right before heating the glass tank. This does away with the time-consuming and dangerous installation in the tank already filled with glass melt.

Sibor® layer structure shown on REM BE microsections:

Sibor® layer structure microsection

  

Highest quality from a single source

We manufacture our molybdenum glass melting electrodes from the raw material to the finished product in-house. We only use the purest raw materials as the source material. This is how we guarantee that our glass melting electrodes meet the highest requirements with a purity of at least 99.97%. This eliminates discolorations and bubble formation.

 
Plansee
Standard
Major and minor
components
Minimum content
[%]
ASTM B387 (361)
Mo 99.97% a Remainder
Impurities Maximum values [µg/g] Minimum values
[µg/g]
Guaranteed
Al 10 -
Cr 20 -
Cu 20 -
Fe 20 100
K 20 -
Ni 10 50
Si 20 100
W 300 -
C 30 100
H 10 -
N 10 20
O 40 70
Cd 5 -
Hg 1 -
Pb 5 -

a) metallic purity without W

Production according to your specific requirements

We have standard sizes in stock. But would you like a special dimension, mechanical machining, coating, a special thread, or cooling ducts? We would be happy to meet your specific requirements.

Plansee standard dimensions and threads

Diameter
[mm (inch)]
Diameter
tolerance [mm]
Surface
quality
Straightness
in mm
related
to 1 m
length
Recommended
cylindrical
thread
Recommended
taper thread
31.75
(1.25")
+/- 0.3 Fine forged < 2.0 M18, M22,
⅞ - 14 UNF
1 - 8 UN 3" TPF
48 +/- 0.3 Fine forged < 1.5 M22, M24,
⅞ - 14 UNF
-
50.8
(2")
+/- 0.0 / -0.8 Fine forged < 1.0 M24, M27,
1 ¼ - 12 UNF
1 5⁄₁₆ - 8 UN 3" TPF
54 +/- 0.4 Fine forged < 1.0 M27, M36,
1 ¼ - 12 UNF
-
60 +/- 0.4 Fine forged < 1.0 M27, M36,
1 ¼ - 12 UNF
-
63.5
(2.5")
+/- 0.4 Fine forged < 1.0 M36
1 ¼ - 12 UNF
1 ¹⁵⁄₁₆ - 8 UN 3" TPF
66 +/- 0.4 Fine forged < 1.0 M36
1 ¼ - 12 UNF
-
70 +/- 0.4 Fine forged < 2.5 M42,
1 ½ - 12 UNF
-
76.2
(3")
+/- 1.0 Fine forged < 2.5 M42,
1 ½ - 12 UNF
2 ⅜ - 6 UN 3" TPF
80 +/- 1.0 Fine forged < 2.5 M42,
1 ½ - 12 UNF
-
90 +/- 1.0 Fine forged < 2.5 M58,
2 ¼ - 8 UN
-
101.2
(4")
+/- 1.0 Fine forged < 2.5 M58,
2 ¼ - 8 UN
3 - 6 UN 3" TPF