PortHole™ Electrochemical Sample Masks
9
PortHole
™
Electrochemical Sample Masks
PortHole Electrochemical Sample Masks define a specified area
of a flat metal sample for electrochemical testing with the PTC1.
PortHole masks are available in areas of 1, 3, or 10 cm
2
to
accommodate any specimen. PortHole masks are fabricated
from vinyl
3M™ Electroplating Tape 470
.
Before applying the PortHole mask, degrease the surface
using a suitable solvent. Remove the backing from the
PortHole mask and place it carefully on the metal sample.
Roll the PortHole mask over the metal sample to make
sure that the tape does not crimp around the perimeter of
the hole.
Carefully press down on the entire surface of the
PortHole mask. Pay special attention to the perimeter of
the hole: it is important to get good adhesion on the
perimeter to minimize the possibility of crevice corrosion.
Use a spatula or a round implement to press the edge of
the tape firmly against the metal sample.
Place the cell body and O-ring of the PTC1 on the PortHole mask so that the exposed area of the sample is
enclosed. Clamp the cell body firmly as described in Cell Setup, and proceed normally.
When the experiment is complete, remove the PortHole mask and discard. If the sample-electrolyte system
tends to undergo crevice corrosion, visually examine the periphery of the hole with a magnifier. If any crevice
corrosion is detected, discard the data for that sample.
If crevicing is particularly prevalent with any sample, consider the following approach. Place the sample in a
benign electrolyte and apply +0.75 volts for 60 seconds to form an oxide film. Remove the sample from the
electrolyte and dry it. Place a PortHole mask in position on the sample. Manually remove the oxide film from
the area exposed by the PortHole mask using a fine emery cloth or a pencil eraser. Perform the electrochemical
experiment.
PortHole™ masks.