07.08.2024 by Aileen Sammler

# The NETZSCH TCT 716 Lambda: Guarded Heat Flow Meter for Direct Measurement of the Thermal Conductivity

Traditionally, Heat Flow Meters (HFM) and Guarded Hot Plates (GHP) are primarily used for insulating materials with larger sample geometries. Meanwhile, the Laser Flash Analysis (LFA) technique measures the Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity in the medium- to high-conductivity range for small samples. The Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity then needs to be calculated by multiplying the Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity with the DensityThe mass density is defined as the ratio between mass and volume. density and specific heat data.

The NETZSCH TCT 716 Lambda bridges the gap by directly measuring the thermal resistance and Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity of medium-conductive materials. Specimen dimensions are 50.8 mm in diameter and up to 31.8 mm thick. This is larger than those used in LFA measurements, making the TCT 716 Lambda particularly advantageous for inhomogeneous samples.

The addition of this instrument completes our comprehensive line of thermal conductivity testers and ensures that we can meet your thermal analysis demands for a wide range of materials.

Thermal resistance and thermal conductivity are critical parameters in determining whether a material is an insulator or a good heat conductor. These properties are essential in designing thermal management systems to prevent overheating and enhance energy efficiency. In plastics injection molding, materials with incorrect thermal resistance can crack, melt, and lose their shape and mechanical properties. Similarly, in laser cutting, materials with low thermal resistance require slower cutting speeds to avoid overheating and damage. The TCT 716 Lambda enables the study of a wide range of solid, rigid or incompressible materials, providing valuable insights into their thermal properties.

GHFM Method

The Guarded Heat Flow Meter (GHFM) method involves placing a specimen between two plates controlled at different temperatures. Multiple RTD sensors measure the temperatures on each side, while heat flux sensors measure the heat flow caused by the temperature gradient. To prevent lateral heat loss an insulating layer (active guard) is incorporated.

This design allows for high accuracy and repeatability in measuring thermal conductivities in the medium range (0.1 to 45 W/(m K)).

Specifications and Design of the NETZSCH TCT 716 Lambda

The TCT 716 is designed to be user-friendly and cost-effective, offering several innovative features:

• Dual Sample Stacks: Enabling tests on a single specimen or simultaneous measurements on two different specimens at the same time.
• No Module Changes: Unlike other commercially available designs that require module changes to cover the full temperature range, the TCT 716 operates seamlessly without such procedures.
• Patented CO2 Cooling System: Eliminates the need for expensive chiller units. Simply connect a pressurized CO2 cylinder to the TCT 716. The liquid carbon dioxide reduces the pressure, forming solid CO2. The sublimation of dry ice removes heat from the measurement system.
• Optimal Stack Dimensions: Capable of analyzing smaller sample sizes compared to conventional Heat Flow Meters, yet larger samples than the LFA, allowing for the measurement of both homogeneous and inhomogeneous samples.
• User-Friendly Software: Offers automatic force and pressure control of the plates, simplifying calibration and sample measurement.

Why Choose the TCT 716? Benefits at a Glance

The NETZSCH TCT 716 Lambda is a significant advancement in thermal conductivity testing, offering unparalleled accuracy and precision, efficiency, and versatility. When you are working with medium conductive materials, this instrument provides the reliable data you need to optimize your thermal management systems.

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