CASTING OF HIGH PURITY OXYGEN FREE COPPER.

摘要

A method and apparatus are provided for making high purity and preferably oxygen free substantially void free and inclusion free copper castings, useful to make sputtering targets. The method comprises melting high purity copper in a covered crucible (17) provided with a reducing gas and insulation, using a coil induction fournace (11). The furnace and crucible, which is disposed between the coil of the furnace and contains molten copper, are positioned above a cooling jacket (23) and the crucible passed continuously downwardly through the opening (27) in the cooling jacket cooling the lower portion of the crucible. A reduced heat is maintained in the furnace to heat the upper poriton of the crucible within the coil and maintain a layer of molten copper over the copper solidifying in the lower portion.