Desiliconization of a Molten Ni-Base Superalloy Using Refining Agents

Abstract Effects of oxide agents, CoO, Cr 2 O 3 , and CaO on desiliconization during vacuum induction melting of Ni-base superalloys were compared. Elemental analyses revealed that all desiliconization agents decreased the Si concentration in the alloy, with CoO exhibiting the highest desiliconization efficiency. Meanwhile, element mapping results suggest that, desiliconization is attributed to redox reactions for CoO and Cr 2 O 3 , whereas the formation of calcium aluminates likely contributed to the desiliconization of the alloy for CaO.