Netsu Sokutei, 29 (4), p. 173, (2002)



Measurement of High Temperature Heat Content by Drop Calorimetry

落下型熱量計を用いた熱量測定は,1000 Kを越えるような高温度域での熱容量,熱含量,相変化熱などの決定法として有効であるが,高温ゆえに実験技術上の問題点も多い。精度よく高温熱含量を測定するために落下型熱量計の加熱炉,温度測定,熱量計,試料系に対しては,様々な工夫や注意を払った設計が試みられており,それらを紹介した。次いで,Shomate関数やQLLR法などの熱含量からの熱容量の導出方法について述べた。また,熱含量測定の応用例として熱力学解析法による合金の熱力学量の導出方法などについて記述した。
Accurate data for high temperature heat contents and heat capacities of substances are valuable for the study of materials and processes at elevated temperature. The heat contents and heat capacities of solids and liquids above 1000 K are determined experimentally by drop calorimetry and the use has been extended to higher temperatures by using modern techniques for measuring and controlling temperature. The general requirements for the drop method are described in terms of furnace assembly, temperature measurement, calorimeter and sample container. Heat capacities can be determined from relative heat content measurements. Shomate function and qusai-local linear regression (QLLR) are useful to accurately derive the heat capacities from the heat contents. Several applications of the heat content measurements are described.