LFA 500
Easy and cost effective measurements
Description
On point
The Linseis LFA 500 Light Flash provides a versatile solution for simultaneously measuring Thermal Diffusivity, Thermal Conductivity, and Specific Heat Values for up to 18 samples.
In industrial applications, understanding the thermophysical properties of materials and optimizing heat transfer in final products has become increasingly crucial. Over the past few decades, the flash method has evolved into the most commonly used technique for measuring the thermal diffusivity and thermal conductivity of a wide range of materials, including solids, powders, and liquids.
Operating Principle of the LFA 500:
In the LFA 500 system, the sample is positioned either on a sample robot, enclosed by a furnace (LFA 500-LT/500/1000), or within one of the five microheaters, which are placed on a movable linear stage (LFA 500/1250). During the measurement, the furnace is maintained at a predefined temperature, and a programmable energy pulse is directed to the backside of the sample. This pulse results in a uniform temperature increase at the surface of the sample.
A highly sensitive, high-speed IR detector is employed to measure the temperature rise on the sample’s surface over time. This data allows for the determination of both thermal diffusivity and specific heat. When the sample’s density (r) is known, the thermal conductivity can also be calculated.
In a nutshell
High-Temperature Configurations:
The Light Flash Series LFA 500 offers various furnace options, including ranges from -100°C up to 500°C, room temperature (RT) up to 500/1000°C or 1250°C, and a boosted option up to 1500°C. These options cater to a wide spectrum of temperature requirements for diverse applications.
Sample Robot:
Every Linseis LFA 500 model comes equipped with a sample robot, ensuring maximum sample throughput. The LFA 500 – 500/1000 model can handle up to 18 samples, while the LFA 500/1250 accommodates up to 5 samples.
Combined “DOUZA” Model:
Introducing the world’s only combined solution for addressing heat loss and finite pulse corrections within the flash method. This all-encompassing model eliminates the uncertainty of choosing the appropriate configuration for your needs.
DOUZA – Combined Model for Translucent Samples:
Tailored to address specific challenges associated with translucent samples, the DOUZA model ensures precise and accurate measurement results.
High-Speed IR or Micro-Heater Furnace:
Thanks to rapid heating and cooling rates, measurements are completed swiftly. The low-mass furnace ensures precise temperature control, eliminating measurement errors stemming from temperature fluctuations at the sample.
Specifications
| Model | LFA 500 (LT/500/1000/1250)* |
|---|---|
| Temperature range: | RT up to 1500°c |
| Heating rate: | 0.01 up to 300°C/min |
| Pulse source: | Light Flash Lamp, user exchangeable |
| Pulse energy: | up to 15J/Pulse (variable pulse energy: software controlled) |
| Adjustable power: | Yes |
| Measuring range alpha: | 0.01 up to 2000 mm²/s |
| Measuring range lambda: | 0.1 to 4000 W/(m∙K) |
| Repeatability cp: | ±3% (for most materials) |
| Repeatability alpha: | ±1.9% (for most materials) |
| Accuracy cp: | ±5% (for most materials) |
| Accuracy alpha: | ±2.4% (for most materials) |
| Pulse length: | Software adjustable |
| – (Unsichtbar, siehe EXTRA CLASS NAME unten) – | – (Unsichtbar, siehe EXTRA CLASS NAME unten) – |
|---|---|
| Samples: | Solids, Liquids, Powders, Pastes, Thin films and more |
| Sample dimensions: | ∅ 3, 6, 8, 10, 12.7 or 25.4 mm square samples 6×6, 10×10 or 20×20 mm |
| Sensor type: | InSb, LN2 cooled |
| Sample Thickness: | from thin films up to 6 mm in height |
| Nr. of samples: | Sample robot for up to 18 samples up to 5 samples (LFA 500/1250) |
| Sample holder: | Graphite, SiC, Al2O3, Metal (others on request) |
| Atmospheres: | inert, oxidizing, reducing, vacuum |
| Electronics: | integrated |
| Data acquisition: | 2 MHz |
| Interface: | USB |
*Specs depend on configurations
Sample holder
Various sample carriers for ideal measurements
Sample Carriers for LFA 500 – LT/500/1000:
- 18 slots for round or square samples measuring 3 mm or 6 mm.
- 6 slots for samples of various shapes (round or square) in sizes 3 mm, 6 mm, 10 mm, or 12.7 mm.
- 3 slots for round samples measuring 25.4 mm or square samples of 20 mm.
Sample Carriers for LFA 500/1250:
- 5 slots for samples with diameters up to 12.7 mm or sizes up to 10×10 mm.
- Custom configurations available upon request.
Sample Holder Options:
- Square sample holder for sample sizes of 3×3 mm, 10×10 mm, and 20×20 mm.
- Round sample holder for sample sizes of 3 mm, 6 mm, 10 mm, 12.7 mm, and 25.4 mm.
- Liquid Container sample holder, Sample holder for lamellas, In-plane or Cross-plane configurations, Sample holder for round samples, Sample holder for liquids and pastes, Torque pressure container.
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Software
LINSEIS’ thermo-analytical devices are all PC-controlled, with individual software modules exclusively designed for Microsoft® Windows® operating systems. The comprehensive software is composed of three modules: temperature control, data acquisition, and data evaluation. The 32-bit Linseis software includes all essential features for preparing, executing, and evaluating measurements, similar to other thermo-analytical experiments.
Key Features of LFA (Light Flash Analysis):
- Precise pulse length correction and pulse mapping.
- Heat-loss corrections.
- Capability to analyze 2- or 3-layer systems.
- Wizard for selecting the most suitable evaluation model.
- Determination of specific heat.
- Assessment of contact resistance in multi-layer systems.
- Multi-method analysis covering DIL, STA, LSR, and LZT.
Evaluation Software:
- Flexibility for automatic or manual input of relevant measurement data (e.g., density, specific heat).
- Model wizard to assist in choosing the appropriate model.
- Finite pulse correction.
- Heat loss correction.
- Multilayer model capabilities.
- Determination of contact resistance.
- Specific heat (Cp) assessment using a comparative method.
Measurement Software:
- Streamlined and user-friendly data input for temperature segments, gases, and more.
- Control over the sample robot for seamless automation.
- Automatic display of corrected measurements after the energy pulse.
- Fully automated measurement procedures, especially beneficial for multi-sample measurements.
Applications
Application: PTFE “Polytetrafluoroethylene”
PTFE, a highly versatile material, finds widespread applications across diverse industries. In the chemical processing and petrochemical sectors, it serves as vessel linings, seals, spacers, gaskets, and well-drilling parts due to its exceptional chemical inertness and corrosion resistance.
In laboratories, PTFE is utilized for tubing, piping, containers, and vessels owing to its resistance to chemicals and the inability of contaminants to adhere to its surface. In the electrical industry, PTFE is employed as an insulator in various forms like spacers and tubing. Moreover, FDA-approved virgin PTFE is extensively used in pharmaceuticals, beverages, foods, and cosmetics industries for components such as conveyor elements, slides, guide rails, and parts in ovens and heated systems.
Additionally, in the semiconductor sector, PTFE serves as an insulator in the production of discrete components like capacitors and plays a crucial role in the chip manufacturing process.
Application: BCR 724 glass ceramic
For the analysis of BCR 724, a standard glass ceramic, the LFA 500 was employed. To conduct the measurement, a small disc with dimensions of 1 mm thickness and 25 mm diameter was excised from a bulk material plate. This disc was then coated with graphite to facilitate the measurement process.
The LFA 500 provides the thermal diffusivity as a direct function of temperature. Concurrently, specific heat (Cp) data was obtained comparatively by measuring a known ceramic standard under the same conditions, using a separate sample position within the same sample holder. By combining these data, the thermal conductivity was calculated, taking into account the product of density, specific heat, and thermal diffusivity.
The results indicate a subtle decrease in thermal diffusivity and conductivity as temperature increases, while the Cp value exhibits an upward trend with rising temperatures.
Application: Graphite reference
An analysis was performed on a graphite sample using the LFA 500. The study involved the direct determination of thermal diffusivity over a range of temperatures from room temperature (RT) to 1100°C. Simultaneously, specific heat capacity was determined by referencing a known graphite standard in a separate sample position during the same measurement.
By combining these findings with the material’s density, the corresponding thermal conductivity was calculated. The results unveiled a characteristic linear decrease in thermal conductivity, which is a common trait in graphite materials. Additionally, the thermal diffusivity displayed a plateau-like behavior above 500°C, and there was a slight upward trend in specific heat capacity as temperature increased.
Application: Reproducibility investigation
The glass ceramic material known as Pyroceram, a registered trademark of Corning and widely used as a standard material in various applications, was subjected to measurement using the LFA 500. The primary objective was to illustrate the reproducibility of thermal diffusivity values.
In this extensive assessment, a total of 18 measurements were conducted using 18 individual samples, each of which was excised from a single bulk block. Each sample underwent separate measurements, and the results indicated a variation within a range of approximately +/- 1% across a temperature span up to 600°C.
Video
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