Light/Laser Flash Analyzer (LFA)

My position: Material Testing > Light/Laser Flash Analyzer (LFA)

Instrument model

NETZSCH LFA 457 MicroFlash/NETZSCH LFA 467

Service model

Commissioned test

Service cycle

9.7 working days

Service items

-80°C (inclusive) - room temperature test temperature points

S$133/point

Test temperature points from room temperature to 400°C (inclusive)

S$75/point

400℃-800℃ (inclusive) test temperature points

S$133/point

800℃-1200℃ (inclusive) test temperature points

S$211/point

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Testing Description

Sample requirement

Examples

Q&A

Documents

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Testing Description

The Laser-Flash method or Laser-Flash-Analyser (LFA) is based on the rise of temperature on one side of a prepared test sample when it is heated by a short laser pulse from the other side. The energy of such a pulse is around 15 J. The temperature increase caused on the sample surface then propagates as a kind of heat wave through the sample until it is detected on the opposite side by an infrared measuring device. The sample itself can be heated to different temperatures in an furnace. In this way, the dependence of thermal conductivity on temperature can be examined.

Following materials can be tested by LFA: metal, ceramic alloy, resin wool, polymer, composite fiber, foam plastic, glass sample insulation material, surface), polyurethane, urine cotton, minerals (wool, rock wool, mineral wool board, reinforcement Composite CRC, sandwich concrete, steel glass panel composite material, cement polypaper slate, etc.

Sample requirements

1. Sample state: block, film sample. Only opaque sample is acceptable.

2. Requirements for thermal conductivity samples in the thickness direction: (1) The surface of the sample is flat and the thickness is uniform, and the data of thickness and density should be provided; (2) For cylinder, diameter of 12.7mm or 6mm, the thickness is 1-4mm (for diameter of 6mm,cannot get the specific heat by the comparison method, so the test can only get the thermal diffusivity!!!); (3)For cube, the length and width are 10*10mm, the thickness is 1-4mm; (4) the thermal conductivity is small and the corresponding sample is thinner.

3. Requirements for thermal conductivity samples in the in-plane direction: (1) The surface of the sample is flat and the thickness is uniform, and the data of thickness, density and specific heat need to be provided; (2) The diameter of the sample is 22-25.4mm, the thickness is 0.1-1mm, and the minimum is not less than 20um

Examples

FAQs

1. What types of materials are suitable for testing by the LFA-427 analyzer?

Most materials except thermal insulation materials are especially suitable for the measurement of medium and high thermal conductivity materials, such as ceramics, metals, polymers, cement, alloys and other materials. Equipped with corresponding testing software, coatings, multi-layer composite materials and Contact thermal resistance and other tests.

2. What are the sample size requirements for the LFA-427 laser thermal conductivity meter?

There are two main test dimensions: one is a small square piece with a side length of 9.7-9.9mm, and the other is a small round piece with a diameter of 12.5-12.7mm, and both are between 0.3-5mm in thickness.

3. What is the suitable thickness of the samples with different thermal conductivity of the LFA?

High thermal conductivity materials (such as metal element, graphite, some high thermal conductivity ceramics, etc.): thermal diffusivity > 50mm2/s, the recommended thickness is 2~4mm; Medium thermal conductivity materials (such as most ceramics, alloys, etc.): the thermal diffusivity is between 1~50mm2/s, and the recommended thickness is 1~2mm; Low thermal conductivity (such as plastic, rubber, glass, etc.): thermal diffusivity <1mm2/s, the recommended thickness is 0.1~1mm.

4. Whether it is the thermal conductivity or thermal diffusivity measured by LFA?

The result of the direct test is indeed the thermal diffusivity. However, according to the formula thermal conductivity λ = thermal diffusivity α * specific heat capacity Cp * density ρ, to know the thermal conductivity, you also need to know the density and specific heat capacity of the test sample, where the density is calculated by dividing the mass by the volume, if the customer's sample The thermal expansion coefficient is very large, so the density should be a function of temperature at this time. It is recommended that the thermal expansion coefficient tester can be used to calibrate the density at different temperatures, but in general, the density is considered to be constant. The test of specific heat capacity is quite difficult. The most commonly used method is the sapphire standard sample method of DSC, but one is expensive, and the upper limit of the test temperature may not exceed 600 °C. Another method is that the laser thermal conductivity meter itself can also be tested. The specific heat capacity of the material can be deduced by testing the thermal diffusion curve of the standard sample with known specific heat capacity and the thermal diffusion curve of tested sample. The deduction mechanism is basically the same as that of the DSC method, but the accuracy is not as high as the DSC method (the laser method may 5%-8% deviation); so the thermal conductivity of the sample at different temperatures (including specific heat capacity and thermal diffusion) can be tested by using a laser thermal conductivity meter under the condition that the requirements are not very high.

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