08:29 Jul-17-2002 Godfrey Hands Engineering, PRI Nadcap, United Kingdom, Joined Nov 1998 281
Re: Thermal conductivity meausurements using ultrasonics : Hello, : I wonder if there is any information regarding measurement of thermal properties of materials using ultrasonics. Is there any equipment commercially available? : Thank you .
Dear Silvia, Quasar International in the USA markets an instrument that determines the mechanical properties of materials (Elastic Constants etc) using Resonant Ultrasound Spectroscopy. This has been used to measure the phase change of materials with temperature, as it can work between temperatures of Liquid Helium and up to 1500 Celius I believe. Look at their web site. www.quasarintl.com and then look at the section about Ruspec.
Re: Thermal conductivity meausurements using ultrasonics Hello,
The thermal properties can be determined using laser-ultrasonic techniques. The absorption of the laser energy by the material causes thermal expansion, which in turn (thermoelastic effect) launches ultrasonic waves. From the thermal expansion, information about thermal properties (e.g. diffusivity, ...) can be extracted (together with the elastic properties, which can be determined from the ultrasonic wave propagation characteristics).
Concerning the determination of thermal properties in a laser-ultrasonic measurement, you could have a look at the following articles: *Graebner et al. Measurement of thermal diffusivity by optical excitation and infrared detection of a transient thermal grating, Rev. Sci. Instrum 66, 3903 (1995) *Jauregui et al. Thermal diffusivities measured by photodisplacement detection of transient thermal grating, Appl. Phys. A 54, 35 (1992) *Käding et al. Transient thermal gratings at surfaces for thermal characterisation of bulk materials and thin films, Appl. Phys. A 61, 253 (1995)
Hope this helps,
Kris Van de Rostyne
: Hello, : I wonder if there is any information regarding measurement of thermal properties of materials using ultrasonics. Is there any equipment commercially available? : Thank you .