Abstract
(1) By melting or casting copper, Si contents in Cu change especially the crucible for melting is important. In nitrogen atmosphere or vacuum Si in the graphite crucible mixes into Cu as impurity, for instance Si 0.037∼0.063%, and by the double melting or more Si increases to 0.098∼0.185%, but the lining of graphite crucible decreases Si contents, Al2O3, MgO or Filit (trade mark) were used. Oxygen in the air affects Si in copper as SiO2 and Si as impurity in copper decreases to 0.001%. (2) The scaling off of cuprous oxide film were studied by Si contents in copper. Over 0.02% Si increases the scaling off of oxide films. (3) The characteristics of rectification on cuprous oxide rectifiers in which copper contain Si 0.006%∼0.165% have been obtained. The forward resistance increases by Si contents, but the reverse negligibly.
