Thermal Diffusivity Measurements on Metals and Ceramics at High Temperatures


Book Description

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 mate rials are reported up to the temperatures indi cated: Pyroceram No. 9606 (1160 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 (1630 C). Heat capacity data have been obtained on Pyroceram No. 9608 be tween room temperature and 650 C. (Author).













An Unsteady-state Method for Measuring Thermal Diffusivity at High Temperatures


Book Description

An unsteady-state method for measuring thermal diffusivity at high temperatures was developed in which experimental heating curves are compared with the simplified solution of the heat conduction problem for various bodies. This method is based on a radiation boundary condition. The thermal diffusivity of refractory oxides measured by this method at 1400° C compares favorably with reported values. The apparatus used was a modification of standard laboratory equipment. Experimental procedures were simple and results were obtained rapidly.