Y. Maeda et al., A HIGH-TEMPERATURE SYSTEM BASED ON THE LASER FLASH METHOD TO MEASURE THE THERMAL-DIFFUSIVITY OF MELTS, International journal of thermophysics, 17(1), 1996, pp. 253-261
A high-temperature measuring system has been developed to undertake me
asurements of thermal diffusivity and specific hear up to 1900 K. The
overall design allows measurements on solids to be undertaken using th
e accepted standard techniques and analytical procedures. The specific
design for molten materials and especially slags is based on the diff
erential threelayer technique utilizing a special cell which can be ac
comodated in the system. In this method, the liquid specimen is sandwi
ched between an upper inner platinum crucible and a lower outer platin
um crucible, to provide a three-layered sandwich. A laser pulse irradi
ates the surface of the upper platinum crucible and the temperature re
sponse of the surface of the lower platinum crucible is observed. For
the purpose of accurate measurement of specimen thickness at the measu
ring temperature, two runs are performed in which the thicknesses are
l and l+Delta l, where I is unknown but Delta l can be set accurately
with a built-in micrometer. The thermal diffusivity is obtained throug
h a curve-fitting method by a personal computer using a three-layer an
alysis with a correction for the radiative component based on the tran
sparent body assumption. Following verification of the basic performan
ce, using solids of known properties and water and ethanol, a continuo
us casting mixture has been evaluated. The initial results on the flui
ds are in good agreement with those in the literature.