An induction furnace for operations up to 3400  C using well oriented graphite

An induction furnace is described for operating in inert atmospheres at temperatures up to 3400°C. The anisotropy of physical properties of oriented graphite has been applied in the construction of crucible susceptors that can resist rapid temperature changes up to 1000 degC sec -1 . One type of pyrolytic graphite crucible with volume more than 200 cm 3 can be evenly heated to 3400° C, without external insulation or shielding, using only 15 kw of power. Another type of orientation is utilized in crucibles made from compacted crystallites of natural graphite which are easy to fabricate. A jig for rotational and translational movement of the susceptor facilitates various operations. Thus, by directing a jet of methane on to a rotating heated substrate, specimens of pyrolytic graphite can be grown of large thickness in the c axis direction.