Investigation of thermophysical properties of refractory materials used in MHD generator channels

Thermal diffusivity, thermal expansion, and electric conductivity of MHD generator electrode materials (88 % ZrO2 - 12 % Y2O3, 82 % ZrO2 - 18 % CeO2, 50 % ZrO2 - 50 % CeO2, 25 % ZrO2 -75 % CeO2, and 20 % ZrO2 - 78 % CeO2 - 2 % Ta2O5) have been measured up to temperatures of 17500C, 15000C, (23000C), and 20000C, respectively. The evaporation rate of magnesia insulation and its thermal and electric conductivities at high temperatures have also been determined. Difficulties in making precise measurements of thermophysical properties on very small specimens of refractory materials, extracted from walls which had been partly destroyed during MHD generator operation, are discussed. (author)