Laser Flash Thermal Diffusivity System
The fundamental measurement of the Flash Method is Thermal Diffusivity, the thermophysical property that defines the speed of heat propagation by conduction: the higher the thermal diffusivity, the faster the heat propagation. As thermal diffusivity is temperature dependent, it is usually measured over the same range of temperatures the material will be required to operate. The thermal diffusivity is related to the thermal conductivity through specific heat capacity and density. The Laser flash method involves uniform irradiation of a specimen over its front face with a very short pulse of energy generated by laser, up to the temperature range to be covered.
The time-temperature history of the rear face of the sample is recorded by high-speed data acquisition from a temperature detector with very fast thermal response. Based on the time-dependent thermogram of the rear face, the sample’s thermal diffusivity is determined from the thickness (L) of the sample and the time the thermogram takes to reach half of the maximum temperature increase (t1/2).
Instrument Specifications:
The instrument is capable of characterizing a wide variety of materials, including polymers, ceramics, carbons, graphite, composites, glasses, metals, and alloys.
Sample temperature range: RT to 1600°C
Thermal diffusivity range: 0.01 to 1000 mm2/s
Thermal conductivity range: 0.1 to 2000 W/mK
Temperature measurement accuracy: better than ±1°C
Laser: Class 1 Nd Class: Laser with maximum energy of 35 J and pulse duration of 300 to 400 µs
Detector: Infrared InSb for the temperature range of RT to 1600°C.
Atmosphere: Air, inert, and vacuum (50x10-3 Torr with mechanical pump)
Repeatability for well-defined samples:
Thermal diffusivity: ±2%
Specific heat: ±3.5%
Thermal conductivity: ±4%
Accuracy for well-defined samples:
Thermal diffusivity: ±2.3%
Specific heat: ±4%
Thermal conductivity: ±5%
Salient Features:
Six 12.7mm samples carousel
• Allows testing 6 samples sequentially in one single run.
• Increases throughput by factor of six.
• For highest quality specific heat capacity measurements 5 unknown samples and 1 reference tested in one single run.
Fiberoptic pulse delivery wand of proprietary design ensures a laser pulse 99% homogenized which then produces very high repeatability (roughly twice as good as any direct firing laser pulse)
Wide range IR detector without iris.
The unique design of IR optics prevents the use of electromechanical iris, and significantly increases ease of operations and long term system reliability.
Laser pulse mapping of each shot for an accurate determination of pulse width and applying corrections accordingly.
Down-firing laser: Laser and power supply are completely independent, stand-alone structures that simplify maintenance and repair.
The IR Neodymium Phosphate Glass laser is fully shielded and completely interlocked for laser and electrical safety.
The down-firing design ensures that sample debris falling off the sample do not risk to damage the bottom window during laser’s shot.
Extensive real-time and post-test data analysis software
Over 15 different loss calculations built in, plus a proprietary “goodness of fit” regression analysis, which automatically picks the best correction for the case.
General Instructions:
• Samples must be dry, moisture free, free of oil and grease.
• Compact powder sample should be used.
• Sample dia is fixed (1.27 cm) and thickness should be (0.15 to 0.5 cm)
• Melting point of the sample should be known
The Samples will be rejected if the above instructions are not followed by the users
