Hot Disk Transient Plane Source (TPS) Technique For Measurement of Thermal Conductivity, Thermal Diffusivity and Specific Heat Thermtest Inc. www.thermtest.com

TPS 3500 Thermal Conductivity Instrument Click to add text www.thermtest.com

Hot Disk Transient Plane Source Technique Absolute method for the measurement of thermal conductivity and thermal diffusivity, with calculation of specific heat and thermal effusivity No calibration required in order to make measurements No contact agent required between sensor and sample Thermal conductivity from 0.001 W/m•K up to 1800 W/m•K Temperatures from - 250 °C up to 1000 °C www.thermtest.com

Different models are available, depending on budget and applications TPS Models Different models are available, depending on budget and applications TPS Model Thermal Conductivity Range (W/m•K) Temperature Range (°C) Hot Disk TPS 3500 0.001 to 1800 -160 to 1000 Hot Disk TPS 2500 S 0.001 to 1000 Hot Disk TPS 2200 0.03 to 500 -160 to 750 Hot Disk TPS 1500 0.001 to 20 Hot Disk TPS 500 S 0.03 to 250 -160 to 300 Hot Disk TPS 500 0.03 to 100 -160 to 200 www.thermtest.com

TPS Testing Modules Different testing modules are available: Standard: for measurement of bulk thermal conductivity and thermal diffusivity of isotropic solids, liquids, pastes and powders Anisotropic: for measurement of directionally-dependent (in-plane and through-plane) thermal conductivity and thermal diffusivity Slab: for thin, highly thermally conducting materials Thin film: for measurement of coatings and stand-alone films 1-Dimensional: for 1D measurement of elongated materials like rods Specific Heat: direct measurement of specific heat www.thermtest.com

TPS Sensors The TPS sensor is comprised of a planar 10 µm double nickel spiral covered on both sides by a protective film (either Kapton, Mica or Teflon depending on the desired temperature and application) Kapton: Up to 300 °C Mica: Up to 1000 °C Teflon: Acidic or corrosive environments Different radii sensors are available From left to right: Kapton, Mica, Teflon www.thermtest.com

Probing Depth The TPS theory assumes that the sensor is in an infinite medium of sample, and thus the probing depth (penetration of heat)must not exceed the boundaries of the samples Thermal diffusivity of a material will determine probing depth during measurements www.thermtest.com

Experimental Parameters An appropriate power output is chosen so as to raise the temperature of the sample between 1 and 4 °C Highly thermally conductive materials will require higher power output than thermally insulating materials A measurement time is chosen so as to allow the introduced heat to penetrate some distance into the sample, but not reach the outer bounds of the sample pieces www.thermtest.com

Two-Sided Experimental Sample Setup The sensor is clamped in to the sample holder The bottom sample piece is placed on the adjustable plate, which is raised so the bottom sample makes contact with the sensor The top sample piece is placed on top of the sensor and a light pressure is applied to ensure good contact between sensor and sample www.thermtest.com

Single-Sided Experimental Sample Setup A single-sided sensor is also available for use if two pieces of the same material cannot be prepared A highly insulative, known backing material is used underneath the sensor to prevent heat loss to the surroundings The sensor is spring-loaded to help ensure good contact between sensor and sample and a weight is also placed on top of the sample to improve contact The sensor can also be placed upside down on a sample www.thermtest.com

Hot Disk Software Experiment parameters are entered on the input screen: - Sample Identity - Available Probing Depth - Sensor Type and Radius - Measurement Temperature - Measurement Time and - Heating Power www.thermtest.com

Hot Disk TPS Software Baseline temperature drift is monitored before the experiment and a correction is applied if needed Temperature increase vs. time graph is plotted, which thermal conductivity is derived from www.thermtest.com

Hot Disk TPS Software 200 data points are collected for each transient measurement Some of these points near the start will be eliminated to remove the effect of contact resistance between the sensor and sample www.thermtest.com

Hot Disk TPS Software Slope is plotted from the T increase vs. time graph, which gives thermal conductivity A residual plot is also included, which compares data to the curve fit, providing extra confidence www.thermtest.com

Hot Disk Software Results are calculated and shown for each experimental run Guiding warnings are provided for Total to Characteristic Time and Total Temperature Increase to ensure optimized parameters are used. A yellow or red warning means that the parameter was slightly off (yellow) or significantly off (red). Simple power and time adjustments can then be made. www.thermtest.com

The hot disk transient plane source technique: Conclusions The hot disk transient plane source technique: - Direct thermal property measurement, no complex calibration required - Is multi-property: thermal conductivity, thermal diffusivity and specific heat - Homogeneous and heterogeneous - Isotropic and anisotropic - Solids, liquids, pastes and powders - No contact agent required - Two-sided and single-sided sensors www.thermtest.com