| 摘要 |
PURPOSE:To produce the title cast target free of shrinkage cavities in good yield by adjusting the temp. of molten metal to be poured into a casting mold from a crucible to a specified crystallization temp. CONSTITUTION:A eutectic rare-earth metal-transition metal based alloy is vacuum-melted in the crucible 101, and the melt 104 is poured into a casting mold 103 through a tundish 102. The tundish 102 is made of a material having excellent heat conductivity. The melt temp. is controlled to a temp. lower than the primary crystallization temp. and higher than the secondary crystallization temp. between the crucible 101 and the casting mold 103, the melt is poured into the casting mold 103 to cast a target for sputtering. At this time, the primary crystal is agitated by the circulation of the melt and flaked, and hence closed cells are not formed in the casting mold 103. Accordingly, when the secondary crystal is solidified and shrunk by the cooling of the casting mold, the melt is rapidly supplied to the shrunk part by the dead head. Consequently, shrinkage cavities due to the solidification and shrinkage of the secondary crystal are hardly formed. |
