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Determination of Thermal Conductivity

The thermal conductivity, also thermal conductivity of a solid or a liquid, is its ability to transport thermal energy in the form of heat. The (specific) thermal conductivity is given in watts per Kelvin and meter and is a temperature-dependent material constant.

The thermal conductivity is to be distinguished from the thermal diffusivity, which indicates the rate at which a temperature change propagates through a substance. Knowledge of the thermal properties of solids and liquids is becoming increasingly important today.

In many applications, such as automotive, aerospace, energy, ceramics, glass, and building materials, very precise information about the thermal behavior of the materials used is of utmost importance.

Thermal management of buildings, for example, is becoming an increasingly important topic due to the skyrocketing energy costs. Heat flows also play a major role in the semiconductor industry, for example when thinking of modern integrated systems such as computer processors.

Applications for thermal conductivity

Application: Measurement of copper-fiber

Introduction and Application: Fiber-reinforced polymers are composite materials made of a polymer matrix reinforced with fibres. The useful attributes (low specific weight, high E-modulus) are being increasingly applied in industrial practices. Through the reinforced fibers its possible to well-directed modifies the properties. Therefore it is important to know the properties especially for high-end applications.

Analysis using LFA: The picture shows the thermal diffusivity and the thermal conductivity in plane are higher than the results normal to the fiber orientation. Consequently this measuring method is a good tool for analysing the material properties and checks the agreement with the favoured application.

Application: Analysis of PEEK

Linseis application Thermal Conductivity - Analysis of PEEK

Introduction and application: Polyetherketone (PEK) are high temperature resistant and belongs to the group of thermoplastics. The most important exponent of the polyetherketone is the Polyetheretherketon (PEEK). The melting point of PEEK is 335°C. Polyetherketone are resistant to organic and inorganic chemicals, to hydrolysis until 280°C. Because of its robustness, PEEK is used to fabricate items used in demanding applications, including bearings, piston parts, pumps, compressor plate valves, cable insulation and medical implants.

Analysis using LFA: The thermal conductivity increases linearly. The thermal diffusivity decreases with an increasing temperature. And the specific heat increases with an increasing temperature. Between 150°C and 170°C are steps in both thermophysical properties (thermal diffusivity and specific heat) due to the glass transition.

Application: Thermal conductivity measurement (DC) using Thin Film Analyser

Linseis application Thermal Conductivity using TFA - Bi0.9Sb0.1 film with a thickness of 100nm

Thermal conductivity of a Bi0.9Sb0.1 film with a thickness of 100nm as function of temperature.

Application: Thermal conductivity measurement (DC & AC) using Thin Film Analyser

Linseis application Thermal Conductivity using TFA - 800nm thin SiO2 - Si3N4 sandwich

Thermal conductivity of an 800nm thin SiO2 / Si3N4 sandwich, measured with the steady state (red) and the transient (blue) technique in the temperature range 80-300K.

Our measuring devices for measuring the thermal conductivity

LFA 500

LFA-500

LFA 500 – LightFlash Analyzer – The robust workhorse

Temperature range:

  • -50 up to 500°C
  • RT up to 500°C / 1000°C / 1350°C (1450°C with boost)
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LFA 1000

LFA-1000

LFA 1000 – True LaserFlash Analyzer – The premium device

Temperature range:

  • -100/ -125 up to 500°C
  • RT up to 1250°C/ 1600°C/ 2000°C/ 2800°C
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THB

Linseis THB

THB – Transient Hot Bridge – Sandwiched Sensor type Thermal Conductivity and Thermal Diffusivity measurements

Service temperature:

  • –150°C up to 200°C
  • -150°C  up to 700°C
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TFA

TFA

Unique device for a comprehensive thin film characterization from the nm to the µm scale

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HFM

Linseis HFM

HFM – Heat Flow Meter – The perfect solution for isolating materials

Temperature range:

  • Fixed 0 to 40°C
  • var. 0 to 100°C
  • -20 up to 75°C
  • var. -30 to 90°C
  • var. -20 to 70°C
Details

TF-LFA

TF-LFA

Thin Film LaserFlash – Time Domain ThermoReflectance (TDTR)- Thermal diffusivity of thin films

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LZT Meter

LZT-Meter

LZT-Meter – Perfect tool for thermoelectric applications

Temperature range:

  • -150 up to 500°C
  • RT up to 800
  • RT up to 1100/1500°C
Details

TIM-Tester

Linseis TIM Tester

The LINSEIS TIM-Tester (Thermal Interface Material Tester) measures the thermal impedance of sample materials and identifies an apparent thermal conductivity for a wide range of materials

  • Automatic pressure adjustment using electric actor (up to 8 MPa)
  • Automatic thickness determination using high resolution LVDT
  • Temperature range: RT up to 150°C or RT up to 300°C (on request)

Details