תיאור
Accurate thermal diffusivity and thermal conductivity measurements between RT and 1250°C 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 until 1250°C without costly consumables.
ZoomOptics – For precise measurement results by an optimized field of view
The patented ZoomOptics system (patent no.: DE 10 2012 106 955 B4 2014.04.03) optimizes the field of view of the detector, thus eliminating any influences caused by aperture stops. The result is a significant increase in the precision of the measurement results.
Ultra-fast sampling rate (up to 2 MHz) and extremely short pulse widths (up to 20 µs) enabling measurement of thin and highly conducting materials
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.
When testing metal (0.3 mm) and polymer foils (30 μm), 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; DE1024241).
Vacuum-tight for defined atmospheres and prevention of oxidation
An internal pump device supports defined atmospheres by an automatic evacuation function prior to each measurement. Additional connections for external pump devices are available. The vacuum tight platinum furnace allows for heating rates up to 50 K/min.
High throughput and precision – 4 samples 4 thermocouples
Effective sample throughput over the entire temperature range is guaranteed by the automatic sample changer (ASC). Each of the ASC’s four sample positions is equipped with its own thermocouple. This results in drastically minimized temperature deviations between the sample and temperature measuring position. The ASC is designed for sample dimensions of 12.7 mm (round) and 10 mm (round and square).
All accomplished while still possessing the smallest footprint
The LFA 467 HT HyperFlash® is the first flash lamp-based LFA system to reach temperatures until 1250°C. One single furnace with an integrated sample changer covers the entire temperature range, providing the small footprint that the LFA 467 HyperFlash® series is well known for. Even at such 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.
Key Technical Data
- Temperature range:
RT to >1250°C - Heating rate (max.):
50 K/min - IR detectors:
- InSb: RT > 1250°C
- Detector refill device
- Data acquisition rate:
up to 2 MHz (for both temperature detection and pulse mapping) - Thermal Diffusivity:
0.01 mm2/s to 2000 mm2/s - Thermal Conductivity:
< 0.1 W/(m*K) to 4000 W/(m*K) - Patented pulse mapping technique
for finite pulse correction and improved cpdetermination - Atmospheres:
Inert, oxidizing, static and dynamic - Vacuum:
10-4 mbar - Sample holders:
for round and square samples - Gas control:
MFC and AutoVac
ZoomOptics
ZoomOptics for more Precise Measurement Results without Measurement Errors
Generally, the area on the sample’s upper surface being scanned by the detector is customized to fit to the maximum sample size up to 25.4 mm. Samples with a smaller diameter are most often covered with a mask or a cap to hide peripheral zones to the greatest extent possible. Since all bodies, however, emit infrared radiation – i.e., even the masking or capping material – the resulting detector signal is inevitably influenced. The extent to which this influence is noticeable depends on the difference in thermal diffusivity between the sample and the mask/cap material. The result – in the final segment of the main temperature rise – can be either a further continuous increase or a premature leveling of the detector signal. In either case, a shift of the evaluated half time occurs, thus falsifying the calculated thermal diffusivity.
ZoomOptics (patent no.: DE 10 2012 106 955 B4 2014.04.03) allows the detector’s field of view to be adjusted until the only temperature increase registered is that of the sample and no influences by the surroundings or mask can have any effect. The pre-set focus value – which covers most applications – is 70%; however, this value can also be individually adjusted by the operator to the given sample geometry.
