Specimen 3 demonstrates the deoxidation of copper.
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The second specimen, shown in the three frames on this page,
is as-cast tough pitch copper. The photomicrograph at left, taken
at 200X, shows copper dendrites in a matrix of copper/copper oxide
eutectic. Note the differently oriented copper grains, each one
containing a distinct dendritic pattern. |
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This copper-copper oxide phase diagram says that liquid
copper can dissolve a great deal of oxygen (as copper oxide) but that
the solubility of the oxide in solid copper is much less. |
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The second photomicrograph
of this specimen, taken at 500X,
illustrates a divorced eutectic. Copper continued to precipitate
on existing copper dendrites during the solidification of this
specimen. There is no distinct eutectic microconstituent, only
small islands of oxide. Specimen 3 demonstrates the deoxidation of copper. |