ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
contamination, and changes have been made in
the design of the capillary tips.
The four measurements listed in Table 2.3.3
were obtained on the same batch of material.
Although the melt was repurified, in place, after
each determination, the formation of plugs in-
dicated contamination during measurement. Further-
more, the batch was kept at high temperatures for
several weeks. When the reactor was opened, it
was observed that some ZrF, had sublimed out
of the solution. These factors indicate that the
values given in Table 2.3.3 must be considered
to be only of a very preliminary nature. It is
encouraging, however, to note that values of the
same order of magnitude were obtained with
capillary tubes of different wall thicknesses.
This behavior seems to indicate contact angles
of less than 90 des. Consequently, the inside
radius of the capillary controls the bubble size,
and no particular uncertainty exists as to whether
the value of the inside or of the outside radius
should be used in the calculations.
118
PROFILE OF A SESSILE DROP
Additional measurements will be made on a
fresh batch of similar composition. When more
reliable values are obtained, the measurements
will be extended to other mixtures of interest.
SURFACE TENSIONS OF MOLTEN SALTS
S. Longer
The sessi le-drop technique for measuring surface
tension, briefly discussed in the previous report,' '
was applied to a number of samples of an NaF-ZrF,
(53-47 mole %) mixture to establish the importance
of a number of experimental variables. Since it
has been demonstrated that NaF-ZrF, mixtures
of this general composition do not wet C-18
graphite, all the experiments described here were
conducted with this material as the supporting
plaque.
A schematic drawing of the sessile-drop apparatus
is shown in Fig. 2.3.8. The sample on its
"S. Longer, ANP Quat. Prog. Rep. Match 10. 1956.
ORNL-2061, P 105.
OPERATED SAMPLE-MANIPULATING RODS
COOLING-WATER JACKET
THERMOCOUPLE WELL
SESSILE DROP
SAMPLE HOLDER
CONSTANT-TEM
UNCLASSIFIED
ORNL-LR-DWG (4642
L SOLENOID-OPERATED
WINDOW SHIELD
Fig. 2.3.8. Diagram of Sessile-Drop Apparatus for Measuring Surface Tensions of Molten Salts.