| 摘要 |
PURPOSE:To provide an oxygen-free copper having low softening temp. and reduced in the electric resistance under very low temp., by subjecting a molten oxygen-free copper in which P content is specified to deoxidation by vacuum treatment. CONSTITUTION:A molten oxgen-free copper containing <=3ppm P is subjected, prior to pouring into a mold, to deoxidation by means of vacuum treatment. By this treatment, the softening temp. is reduced and the electric resistance under very low temp. is also reduced. This high-purity oxygen-free copper is applicable to copper foil for flexible printed circuit board, stabilizing material for superconducting use, etc.
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