M00016645
New product
ISO DIS 22007-6 2013 Edition, April 8, 2013 PLASTICS - DETERMINATION OF THERMAL CONDUCTIVITY AND THERMAL DIFFUSIVITY - PART 6: COMPARATIVE METHOD FOR LOW THERMAL CONDUCTIVITIES USING A TEMPERATURE-MODULATION TECHNIQUE
In stock
Warning: Last items in stock!
Availability date: 07/14/2021
Description / Abstract:
The thermal conductivity of materials that are poor conductors
of heat is usually determined by measuring the larger temperature
gradients in the sample produced by a steady flow of heat in
one-dimensional geometry. In order to reduce the errors of
radiation and convection, it often requires large, precisely shaped
samples and extreme care to be used successfully.
This international standard specifies a modulated temperature
method realizing the measurement of thermal conductivity. An input
of temperature deviation is less than 1 K, and a double lock-in
method is applied to amplify the small temperature modulation.
The ISO22007-3 specifies one of the modulated temperature
methods where the phase shift is measured in the thermally thick
condition kd >>1
(k=(ω/2α)
1/2, ω: angular frequency of
temperature wave, thermal diffusivity, d: thickness of the
specimen). In this condition, the backing material does not affect
on the phase shift results on the sensor, on which temperature wave
decays exponentially.
On the other hand, if kd << 1, the decay of
temperature modulation is influenced by the backing materials.
Based on this principle, this standard specifies the method to
determine the thermal conductivity of the sample (as a backing
material), comparing the decay of temperature wave detected on both
surfaces of the probe material.
Thermal conductivity is determined from the correlation between
the thermal impedance and the decay ratio of amplitude using two
reference materials measured at the same frequency and temperature.
For instance, if water and air are chosen for reference materials,
thermal conductivity is determined in the range from 0,026 W/mK to
0,6 W/mK.
The covering range is adjusted with the reference materials and
the probe materials.