LASER FLASH EQUIPMENT

Thermal diffusivity range: 10^-3 to 1 cm² /s

Samples under study:

Rocks

Temperature Range:

Room temperature up to 2200 ºC. (High temperature furnace.)

Room temperature down to -150 ºC. (Cryogenic unit.)

Uncertainty:

+/- 5 %.

Calibration of the instrument:

Some Results:

Poco Graphite AXM-5QL;

Pyroceram 9606;

Fused silica;

Copper;

Austenitic stainless steel.

Methodology:

The laser flash is based on optical methods with a strong impact, used for the measurement of the thermal diffusivity of solids. The success of this method owes, essentially, not only to the reduced time interval necessary for the realisation of the measurements, but also because of the simplicity of the sample, the ability to study very different substances and the possibility to work at high temperatures.

Conceptually, the laser flash method is very simple. A small disc of the material to be studied is kept at a constant temperature and thermally isolated from the surroundings. One of its faces is subjected to fast axial heat pulse. The temperature of a certain point on the rear face of the sample is monitored as a function of time. This assumption is valid in the case of homogeneous materials.

The determination of the thermal diffusivity can be made in several ways. In the simplest case, the time that the rear face takes to reach a half of its maximum value is measured.

Instrument characteristics:

(Financed by the PRAXIS Program - FCT)

ANTER CORPORATION (USA)

MODEL FL5000

SPECIMEN DIAMETER	6 to 12mm (typical)
SPECIMEN THICKNESS	1 to 6mm (typical depending on material)
TEMPERATURE REGION	Room temp. up to 2200°C
TEMPERATURE RISE SENSOR	Optical, solid state, LN2 cooled
LASER	Neodymium glass, 35j
STORED POINTS	30,000
DATA RATE	20 KHz (max)
DIFFUSIVITY	10^-3 to 1 cm² /s
ACCURACY	±5% (of range decade)
REPRODUCIBILITY	±3% (of range decade)

Photos (click to view the full size):

Lab:

Rock Samples: