Surface Condition of W/Mo Crucibles Has a Great Influence on Sapphire Growth

Saphhire

Do you know that the surface condition of molybdenum and tungsten crucible has a great influence on sapphire growth? Let us see the details in the following:

If the surface of the crucible is too rough, the sapphire cannot be released or can only be partially released from the wall of the crucible, which results in cracks and faults in the crystal. Not only that: The crucible itself is also damaged in the process and has to be reworked or replaced earlier than planned.

Our pressed-sintered crucibles made of tungsten or molybdenum has a surface roughness of less than 0.8 µm. The sapphire can be extracted from the crucible without difficulty and without damaging the surface of the crucible. For the sapphire producers, this results in fewer complexes and expensive reworking of the surface of the crucible. The cycles run smoothly and deliver high-quality ingots. And there's another advantage: The smooth surface is less susceptible to corrosion caused by the aggressive melted sapphire. This increases the service life of the reusable tungsten/molybdenum crucibles.

Crucible with Smooth Surface

Do you use molybdenum melting crucibles? We are glad to deliver these crucibles with ultra-smooth surface too. Talk to us!

Tungsten and Molybdenum Crucible Applied in Sapphire Production

Molybdenum Crucible

During sapphire production, Al2O3 - the compound that is to become the future single crystal - is melted in molybdenum crucible and tungsten crucibles. It is in the Kyropoulos process that our pressed-sintered crucibles show their strengths to best effect. They are repeatedly heated to more than 2 000 °C (3632 °F) and then cooled down again. This process, which would cause fissures and distortions in other materials, is not a problem for our tungsten and molybdenum products.

With our many years of experience in the field of powder metallurgy, we produce crucibles of a particularly high density and purity. By correctly filling the mold used for the crucible and carefully controlling the temperature distribution during sintering, we achieve uniform wall and base thicknesses - an important prerequisite in achieving the high level of creep resistance that characterizes our crucibles.

If you are interested in such a crucible, please feel free to contact us.