THERMAL MEASUREMENTS

Neotim’s philosophy also applies to service delivery: offering specific solutions tailored to your needs.

Neotim relies on its own means of measurement as well as those of the Centre RAPSODEE (Centre de Recherches d'Albi en génie des Procédés des Solides Divisés, de l'Energie et de l'Environnement, UMR CNRS 2392) of the Ecole des Mines d'Albi-Carmaux and on several devices of physico-chemical analysis or methods of thermal metrology allowing to characterize any type of materials (solids, liquids, pasty, etc.) under various atmospheres.

We also carry out in-situ measurement campaigns using existing or specifically developed sensors.

THERMOPHYSICAL CHARACTERIZATION

Measure of :

  • Thermal conductivity
  • Thermal diffusivity
  • Specific heat
  • Thermal effusivity

Les méthodes de mesure :

  • Hot-Disk
  • Hot wire
  • Flow meters
  • Flash method
  • Calorimetry

In various atmospheres :

  • Vacuum : from 10-4 mbar to 1 bar
  • Temperature : < 750°C
  • In controlled humidity
  • Under inert gases

We also produce specific sample holders adapted to high temperatures or measurements on phase-changing materials.

Measurements on all types of materials : solids, liquids, paste, aerogels, ...

The measurement methodology

Most of the thermophysical characterization methods we use are based on the use of shock probes. They make it possible to create a thermal excitation of the material, the response to this excitation being dependent on these thermal properties.

FP2C

La méthode du fil chaud permet d'estimer la conductivité thermique d'un matériau à partir de l'évolution de la température mesurée par un thermocouple placé à proximité d'un fil résistif. La sonde, constituée du fil résistif et du thermocouple dans un support isolant en kapton, est positionnée entre deux échantillons du matériau à caractériser.

Hot Wire probe

Conductivity from 0,02 to 5 W.m-1.K-1
Measuring temperature from –60 to 100 ° C and 100 to 250 ° C with a specific optional probe
Samples: at least 60x40 mm, from several millimeters thick for the insulators to a few centimeters for the more conductive

Hot Surface probe

Thermal effusivity: from 20 to 10,000 J.m-2.K-1.s-1/2
Measurement temperature: -60 to 100 ° C
Minimum sample size: 50 x 50 mm, from a few millimeters thick for an insulator to a few centimeters for a conductor

Hot Ring probe

Diffusivity from 0.1 to 4mm².s-1
Measuring temperature from –60 to 100 ° C
Samples: at least 25 x 25 mm, from a few millimeters thick for an insulator to a few centimeters for a conductor.

Needle probe

Conductivity from 0,02 to 5 W.m-1.K-1
Measuring temperature from -20 to 100 ° C
Samples: at least covering the metal part of the probe, from a few millimeters thick for an insulator to a few centimeters for a conductor.

CTMF

La méthode fluxmètrique consiste à produire un gradient de température suivant l'épaisseur de l'échantillon à caractériser et d'en mesurer le flux de chaleur qui le traverse.

  • Conductivity from 0.01 to 1 W.m-1.K-1
  • Measuring temperature from 15 to 100°C
  • Samples: 150 x 150 mm, thickness from 5mm to 20mm

Nous avons développé notre propre appareil méthode fluxmétrique que nous avons baptisé CTMF.

HOT-DISK

Le Hot Disk est un analyseur de propriétés thermophysiques développé par une société suédoise qui utilise la technique brevetée de la source plane transitoire. Une sonde constituée d'une double spirale de nickel sur un support isolant en kapton ou en mica (selon la température de mesure) est positionnée entre deux échantillons du matériau à caractériser.

Le Hot Disk mesure la conductivité et la diffusivité thermique et permet d'estimer la chaleur spécifique.

- Kapton probe
- Conductivity from 0,01 to 500 W.m-1.K-1
- Measuring temperature -30 to 750°C
- Samples: from a few millimetres thick for insulators to a few centimetres thick for conductors. Consult us for other dimensions.

FLASH METHOD

The principle of the flash method is based on the transient analysis of the temperature of the rear surface of a cylindrical sample, initially isothermal, subjected to a photothermal pulse on its front surface. This thermal disturbance is achieved by a flash. The duration of the pulse is in the millisecond range. The temperature rise is measured on the rear side using a separate contact thermocouple. A mathematical model is then used to calculate the thermal diffusivity of the sample.

- Thermal diffusivity from 0,01 to 100 mm2.s-1
- Measuring temperature from 20 to 200°C.
- Cylindrical samples with a diameter of 35mm, thickness depending on the thermophysical properties.

CALORIMETRY

In particular, calorimetric analysis makes it possible to measure the specific heat of the material. Two devices from the SETARAM range are used in the laboratory :

TG-DSC 111: The TG-DSC 111 performs the simultaneous measurement DSC (thermal flux variation) and ATG (mass variation) on the same sample. The DSC 111 sensor consists of two heat cells mounted in opposition in the middle of two tubes made of refractory material. The assembly is arranged in a heated metal block. The crucible is completely wrapped by the thermopile, which ensures a measurement of all heat exchanges. Measurements up to 800°C.

Calorimeter Calvet C80: calorimeters Calvet are differential devices. Two thermobatteries surround a measuring cell in which the sample to be studied is placed and a reference cell containing a thermally inert product. The differential analysis makes it possible to eliminate all the parasitic thermal phenomena that are not related to the reaction to be studied and thus to obtain a very high sensitivity. Available in an isothermal version or programmed between room temperature and 300°C, the C80 can detect very low power thermal phenomena.