The cylinder method with axial heat flow can be
used for thermal conductivity measurements of metals
with thermal conductivities up to 500 W m−1 K−1
in a temperature range between about 4 K and 1000 K.
Comparing the principle of operation and the mathematical
model, the cylinder method and the guarded hot
plate method fully agree. The most important difference
is the sample geometry, which is a flat plate or disk for
the guarded hot plate method and a long cylinder or rod
for the cylinder method. This is due to the fact that the
main difficulty for measurements of materials with high
thermal conductivity (e.g. metals) is the determination
of the temperature difference. In this case the contact resistances
between the sample and the heater and between
the sample and the cold plate must be considered. The
minimization and determination of the resulting temperature
drop across these thermal contact resistances is the
most important criterion for the optimization of this type
of instrument.
Therefore, guarded hot plate and cylinder method
are realizations of the same measurement principle optimized
for different ranges of thermal conductivity.
Part C 8.1
Springer Handbook of Materials Measurement Methods