struers Tenupol-3 Gebrauchsanweisung Seite 22

Tenupol-3
Instruction Manual
2.9.2. "Electrolytic Blanking"
When equipped with the 2.5 mm jets the Tenupol-3 may be used for cutting
out 3 mm (2,3 mm) specimens electrolytically in the 10 mm specimen
holder. The larger specimen, which should be 0.1-0.5 mm thick, is first
degreased in alcohol. One side of the specimen is covered completely with
a special acid-resistant tape, having an acid-resistant adhesive. On the
other side are stuck 1-4 discs of tape of 3 mm (2.3 mm) diameter within a
circle of 10 mm diameter The tape is available as a kit (accessory: TENKI).
The tape must be pressed securely against the metal. The specimen is now
put into the specimen holder, so that there is a free area, which can be
polished away, around the small tape discs. When the holder has been put
into the cell the cathode on the side, where the specimen is completely
covered, is disconnected by pulling out the banana plug. The specimen is
then polished in the usual way until the exposed area has disappeared. The
3 mm (2.3 mm) metal specimens will now be present under the tape discs.
They are disengaged, washed and are ready for the final thinning.
The standard supplied jet holders have jets with an inside diameter of 1
mm. For thinning and electrolytic blanking with the 10 mm specimen holder,
however, jets with an inside diameter of 2.5 mm have to be used. When
using highly viscous electrolytes it may be necessary to use 2.5 mm jets
(TETET) also in connection with 2.3 mm and 3 mm specimen holders. It is
easy for the user to carry out the change between 1 mm and 2.5 mm jet
holders.
2.9.3. Final Thinning
This will normally consist in polishing of 3 mm (2.3 mm) diameter specimens
with the 1 mm jets. The polishing is carried on until a small hole appears
and will be stopped as soon as the IR-light breaks through the specimen.
By varying the photo sensitivity the hole size can be changed. Position 10
implies maximum sensitivity causing a small hole to be seen at once. The
process can be terminated automatically by means of the photocell which is
mounted on the polishing cell. The current is broken and a beeper is
activated.
As soon as the polishing is finished the specimen holder must be taken out
and opened in a small bath of e.g. ethanol or distilled water, kept ready
close to the cell. From this the specimen is transferred to a bath of e.g.
ethanol by means of a pair of tweezers. It may then be laid on a piece of
filter paper, where it dries in a couple of seconds and is ready for
examination or storing.
Thinned specimens may be kept under vacuum in a desiccator with
silicagel. In most cases they can also be kept in glycerol, which will protect
them against the action of the atmosphere.
20