Figure 9.6.1: Clay graphite crucibles available from Morgan Molten Metal Systems
Clay graphite crucibles perform better than graphite crucibles for melting copper, due to their lower cost, better oxidation resistance and lower electrical conductivity. The lower conductivity of the clay graphite material reduces the absorption of the induction field by the crucible, allowing more of the current be induced directly into the copper, thereby speeding the melting of the copper.