Thermal conductivity of alumina measured with three techniques

Three common ASTM methods (calorimetry, hot-wire, and laser-flash) for determining the thermal conductivity of refractory ceramics were compared using a commonly available bulk material having a microstructure sufficient for all three methods of analysis. Experimental measurements were made between 20-1200degreesC on a fine-grained, 94% pure aluminum oxide using each technique. Results from the hot-wire and laser-flash methods were found to be similar and in line with theoretical and literature values. Values obtained by the calorimetry method were found to be lower than those of the other two methods, with a greater deviation at lower temperatures than at higher temperatures.