THERMAL DIFFUSIVITY MEASUREMENTS ON METALS AND CERAMICS AT HIGH TEMPERATURES

摘要

The U. S. Naval Radiological Defense Laboratory flash method of measuring thermal diffusivity has been extended to ceramics at high temperatures. Several problems encountered in applying this technique to ceramics are discussed:namely, heating the samples to a uniform temperature over the sample face; overcoming the transparency of the specimens to the radiation from the xenon flash lamp; and correcting for radiation heat losses from low thermal conductivity ceramic specimens at higher temperatures. Measurements of the thermal diffusivity of the following materials are reported up to the temperatures indicated:Pyroceram No. 9606 (ll60°C), Pyroceram No. 9608 (1210°C), Pyroceram No. 9690 (1150°C), beryllium oxide (1780°C), aluminum oxide (four types) (1730°C), magnesium oxide (two types) (1370°C) and two spinels (l630°C). Heat capacity data have been obtained on Pyroceram No. 9608 between room temperature and 650°C.