Preparation of Highly Perfect Aluminum Crystal by Cold-Crucible Induction Melting in Ultra-high Vacuum

抄録

To make a highly perfect aluminum crystal, high purity aluminum was melted in ultra-high vacuum of 2×10⁻⁷ Pa for 2 h using a cold-crucible induction furnace. The surface of as-melted ingot had a metallic luster, and heavy oxidization on the surface was not recognized. In the ingot, a large cylindrical-single crystal of diameter 60 mm and length 40 mm grew and dislocation density in the crystal was about 10⁷ m⁻². The purity of the refined aluminum was estimated to be near 99.9999% from the residual resistance ratio. The impurity elements removed with high purification efficiency had a distribution coefficient of less than unit. A large amount of highly perfect aluminum crystal of ultra-high purity was produced by melting only once under the ultra-high vacuum.