Glassy carbon

Overview of glassy carbon crucibles

Glassy carbon is high-temperature resistant in inert gas or vacuum environments up to 3,000 °C. Unlike all other ceramic and metallic high-temperature materials, glassy carbon increases in strength with a rise in temperature up to 2,400 °C. Glassy carbon is thus twice as strong at 2,400 °C as it is at room temperature.

The material does not become fragile at high temperatures and has a high degree of resistance to thermal shocks. Repeated high-level heating and cooling are not problematic.

Principal characteristics of glassy carbon crucible

• Low heating and smelting times, as the metal melts faster and more homogeneously. Glassy carbon crucibles have a longer life-span than those made of ceramics or ordinary graphite.

• Glassy carbon crucibles are not porous.

• Its high degree of purity, the low specific surface area and the isotropic structure of a carbon crucible give rise to a slight oxidation which produces protective gas above the smelted metal helping to prevent the formation of oxide on the molten metal.

• Uniform casting is possible without wetting the surfaces of the crucible. This property remains intact throughout the life-span of the product.

• With their high resistance to thermal shocks, crucibles made of glassy carbon will not crack even when placed on cold surfaces when still hot.

• Glassy carbon crucibles can be used in induction heating.

• Glassy carbon crucibles are ideally suited for smelting palladium alloys and other alloys containing a percentage of noble metals. Glassy carbon crucibles are also used with rare metals and titanium alloys.

• Glassy carbon crucibles are not to be used for the smelting of steel or ferrous alloys.

Available standard products of glassy carbon crucibles

• Cylindrical crucible
• Conical crucible (high angle)
• Conical crucible (low angle)
• Lid
• Crystal growth crucible
• Crucible with dispensing spout
• Boat, incinerating dish

Other types of glassy carbon crucibles are also available

• Bars, 1 to 10 mm diameter
• Plates, 0.5 to 6 mm thickness
• Films, 60 to 180 μm thickness
• Tubes upon request
• Powders

Technical data of glassy carbon crucibles