We will report the measurements under the control of variation of properties of the specimens (picked from the same manufacturing lot with identical bulk densities), measuring conditions, and by designating the person to measure. We adopted guarded hot plate method (GHPM) and hot-wire method (HWM) for the measurements. We confirmed that the thermal conductivities measured toward both in-plane direction(parallel direction toward blanket) and out of plane direction(orthogonal direction toward blanket) by both methods stayed within 5% variation coefficient. In the case of the GHPM, the thermal conductivities toward in-plane direction were 1.3 to 1.4 times higher against toward out of plane direction while in the case of HWM the former were 1.1 to 1.2 higher than the latter. The thermal conductivities measured by the GHPM toward in-plane direction were higher than those by the HWM and the difference decreased by the advancement of temperatures. We also noticed that the thermal conductivities measured by the GHPM toward out of plane direction were higher than those by the HWM when temperatures were under 600 t but this was reversed after temperatures went over 600°C.
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