Development of High Temperature Drop-Calorimeter

本工作的目的是研制一台适用于1500 ~ 2000 K温度范围的高温滴式量热计，主要研究结果如下：1）制作了8个铬酸镧加热元件的加热炉，加热元件外径为14 mm，长度为90 mm。在700 ~ 2000 K温度范围内，炉内温度均匀区为15 mm。2）样品容器采用真空密封的氮化硼石英池，避免了样品在700 ~ 1900 K温度范围内氧化所带来的实验困难。滴下装置是为了避免样品池到达量热计管底时由于重力引起的冲击而破裂而开发的。4）用蓝宝石作为标准物质测定量热计当量，它是17.700 kJ/K。5）这种高温降的准确性-在700 ~ 1800 K温度范围内对金进行了测量，验证了量热计和实验程序的正确性，测量结果的一致性在3%以内6）在700 ~ 1820 K温度范围内测量了硅的高温热含量，采用固相的Shomate函数和液相的最小二乘法分别推导了热容和热含量方程。

The aim of this work is the development of a high temperature drop-calorimeter used over the temperature range of 1500 to 2000K.The results obtained are summarized as follows :1) The heating furnace used eight heating elements of the lanthanum chromite of 14 mm outer diameter, 90 mm length was made. A uniform temperature zone of the furnace is 15 mm in the temperature range of 700 to 2000K.2) A vacuum sealed quartz cell kept a boron nitride was used as a sample container to avoid the experimental difficulties arising from oxidation of samples at temperature range of 700 and 1900K.3) The dropping device was developed to avoid a breakdown of the sample cell due to a shock caused by the gravitational force when the cell reached the bottom of tube in a calorimeter.4) The calorimeter equivalent was determined using sapphire as standard material, and it was 17.700 kJ/K.5) The accuracy of this high temperature drop-calorimeter and experimental procedure was tested by performing the measurements for a gold in the temperature range from 700 to 1800K.The results agree within 3% with literature values.6) High-temperature heat content of silicon was measured over the temperature range 700 to 1820 K.The heat capacity and heat content equations were derived by use the Shomate function for solid phase and least-squares method for liquid phase.