Molybdenum crucible

tungstenfor high-temperature applications

Overview
Crucibles for high-temperature single-crystal production and material processing, available as formed (drawn/rolled) or pressed‑sintered parts in molybdenum (Mo) and tungsten (W). Designed primarily for sapphire (Al2O3) melting and solidification in HEM and Kyropoulos processes, they are also suitable for evaporation and melting of other refractory materials.

Formed crucibles
Formed crucibles (Mo, W) feature thin, uniform walls with high creep resistance and controlled geometry. They are optimized for HEM (Heat Exchanger Method) use where consistent wall thickness, high density and material purity are required to minimise contamination and ensure stable crystal growth.

Pressed-sintered crucibles
Pressed‑sintered tungsten crucibles are engineered for Kyropoulos processes and other cyclic high-temperature applications (>2,000 °C). Low surface roughness (typ. < 0.8 µm for pressed‑sintered W) improves release of sapphire from the crucible wall, reduces crystal cracking and limits rework or premature crucible replacement. Molybdenum versions with ultra-smooth surfaces are also available.

Performance & manufacturing
Produced using powder metallurgy with controlled mould filling and precise sintering temperature profiles to deliver high density, homogeneous wall and base thicknesses and elevated purity. Source materials are produced in-house (hot-rolling mill for refractory metal sheets) enabling large-format production and consistent quality control.

Applications

• Sapphire single-crystal growth (Al2O3 melts)
• HEM (Heat Exchanger Method) and Kyropoulos processes
• Evaporation and melting of high-temperature materials
• High-temperature furnace components and cyclic thermal processes

Key benefits

• High material purity to prevent crystal contamination
• Low surface roughness for clean crystal release and reduced defects
• Optimised wall/base thickness for high creep resistance
• High corrosion resistance against aggressive melts
• Large available formats and repeatable manufacturing quality

Technical specifications

• Materials: molybdenum (Mo) and tungsten (W); other refractory metals on request
• Typical processes: HEM (formed crucibles), Kyropoulos (pressed‑sintered crucibles)
• Surface roughness (pressed‑sintered W): typ. < 0.8 µm
• Temperature resistance: suitable for repeated cycles > 2,000 °C
• Formed crucibles: diameters approx. 10 mm up to 600 mm; heights up to approx. 800 mm (larger diameters possible with reduced sidewall height)
• Pressed‑sintered crucibles: diameters up to approx. 1,000 mm; heights up to approx. 900 mm
• Production: powder metallurgy — pressing and sintering with controlled mould filling
• Benefits: consistent wall/base thickness, high density and purity, lower crystal defects and reduced crucible rework