LFA 467 HyperFlash® Series
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Light Flash Apparatus LFA 467 HyperFlash® Series Method, Technique, Applications of Thermal Diffusivity and Thermal Conductivity Analyzing & Testing

THE FLASH METHOD Thermal Conductivity/Thermal Diffusivity How much heat is being transferred, and how fast? Researchers and engineers are interested in the best way to thermally characterize highly conductive materials at cryogenic and moderate temperatures or ceramics and refractories at elevated temperatures. Many challenges can only be met with precise knowledge of two fundamental thermal properties: diffusivity and conductivity. One accurate, reliable and elegant solution is offered by the Flash Method. This method allows for the meeting of challenges typically arising in heat transfer...

Light Flash An Efficient Method for Determination of Thermophysical Properties The front surface of a plane-parallel sample is heated by a short energy light pulse. From the resulting temperature excursion of the rear face measured with an infrared (IR) detector, thermal diffusivity and, if a reference specimen is used, specific heat are both determined. Combining these thermophysical properties with the density value results in the thermal conductivity as follows: where λ = thermal conductivity [W/(m·K)] a = thermal diffusivity [mm²/s] cp = specific heat [J/(g·K)] ρ = bulk density [g/cm3]....

DEFINED ATMOSPHERES The atmosphere can be controlled via three integrated frits or optionally via mass flow controllers for one protective and two purge gases. All gas controls offer operation in oxidizing, inert, dynamic or static atmospheres. Additionally, pumping allows for measurements under reduced pressure. INTELLIGENT INSTRUMENT SETUP AND FLASH SOURCE The LFA 467 HyperFlash® is designed as a vertical system with the flash source at the bottom, the sample in the center and the detector on top. A xenon lamp serves as the flash source. The variable pulse energy is software-controlled...

HIGHEST SAMPLE THROUGHPUT -16 SAMPLES SIMULTANEOUSLY The LFA 467 HyperFlash® has an integrated automatic sample changer for up to 16 samples. A tray for four holders, each containing four samples, can be used with round and square samples. A considerable reduction in operator intervention is also effectuated through the use of a high volume liquid nitrogen Dewar. ONE FURNACE - WIDE TEMPERATURE RANGE Measurements from -100°C (i.e., below the glass transition temperature of rubber materials) to 500°C can be carried out with a single instrument setup. Neither the furnace nor the detector has...

HIGH TEMPERATURES WITH XENON FLASH The LFA 467 HT HyperFlash ® is based on the already-established LFA 467 HyperFlash® technology and requires no laser class due to the innovative light source system. The long lifetime of the xenon lamp provides cost-effective measurements up to 1250°C without costly consumables.

WIDEST TEMPERATURE RANGE WITH THE SMALLEST FOOTPRINT The LFA 467 HT HyperFlash® is the first flash-lamp based LFA system to reach temperatures up to 1250°C. A single furnace with an integrated sample changer covers the entire temperature range, providing the small footprint for which the LFA 467 HyperFlash® series is well known. Even at elevated temperatures, an efficient internal water cooling circuit keeps the temperature of the surrounding components within a safe range, thereby reducing the liquid nitrogen consumption of the IR detector. P TO 1250°C U DEFINED ATMOSPHERES PREVENT...

The data acquisition rate of the LFA 467 HyperFlash® series was increased to 2 MHz. This acquisition rate applies to both the IR detector and the pulse mapping channels. Thereby, highly conductive and/or thin materials requiring very short test times can be reliably tested. Thin and Highly Conducting Materials By Ultra-Fast Sampling Rate When testing metal (0.3 mm) and polymer foils (30 |um), an optimum sampling rate and pulse width can be selected. The patented pulse mapping system accounts for the finite pulse width effect and heat losses (patent no.: US7038209 B2; US20040079886;...

FOR PRECISE MEASUREMENT RESULTS samples sample holder furnace light source Simplified Handling Allows for View of Just the Sample Surface Between the detector and sample, a stepper-motor-actuated lens optimizes the field of view by software control. This helps to prevent measuring artifacts due to contributions from the aperture stop, often characterized by a delayed IR signal. Signal distortions from the sample’s immediate surroundings like masks or aperture stops are avoided. The precision of the test results is thus greatly improved. This feature is particularly valuable for...

OPTIMIZED FIELD Lack of ZoomOptics Allows for Distortion from the Aperture Stop IR Detector Lens Field of View In current LFA systems, the field of view is fixed and wide enough to accommodate large-diameter samples. When testing smallerdiameter samples, aperture stops are commonly used in an attempt to minimize influence of the surroundings. This often results in a significant distortion of the thermal curve to the extent that the detector senses not only the temperature excursion of the sample, but also any fluctuations from the aperture stop. Consequently, the thermal curve would show...

ZoomOptics ZoomOptics Prevents Any Distortion from the Aperture Stop IR Detector Lens Field of View By using the new ZoomOptics of the LFA 467 HyperFlash®, it can be ensured that the IR signal originates solely from the sample surface and not from any surrounding parts. Therefore, both large and small samples can be tested with an optimal sensing area. Aperture stop Field -1000 when using ZoomOptics; no influences from the aperture stop occur of view 0 1000 2000 3000 4000 Time /ms In contrast with the previous configuration, the lens has been shifted for an adequate field of view. The...

LFA 467 HyperFlash® – Sample Holders for Special Appliations Flexible & Efficient For samples with low viscosity and polymer melts Two Detectors – Always Remote Sensing In‐plane sample holder Two user-exchangeable detectors are available. The standard indium antimonide (InSb) detector is suitable between room temperature and 500°C (LFA 467 HyperFlash®) or 1250°C (LFA 467 HT HyperFlash®), respectively, while the optionally available mercury cadmium telluride (MCT) detector allows for measurements from -100°C to 500°C. The detectors can be equipped with a liquid nitrogen auto-refill system –...