Copper "Trees" on Iron
This is an example of copper trees growing on a small
particle of iron in a large transformer retro-filled with
a natural ester oil.
Transmitted Crossed Circular Polarized Light and Darkfield Reflected Light Illumination
Definition/Function:
Copper trees will grow on a small fragment of iron in transformer oil when copper is
taken into solution in the oil.
Copper will plate the iron if only very low levels of copper are present.
Significance in the Environment:
This indicates that the oil is corrosive to copper and that some of the copper compounds
formed are soluble in the oil.
Characteristic Features:
The reddish color of the copper stands out in sharp contrast to the light gray of the
iron. Even in low concentrations the copper plating out
on the iron will be easily visible.
Associated Particles:
References:
