DEVELOPMENT OF DROP-AND-CATCH ULTRA-HIGH TEMPERATURE CALORIMETER

A new instrument is being developed in the Peter A Rock Thermochemistry Laboratory at UC Davis for ultra-high temperature enthalpy measurements on refractory oxides. The design includes the sample suspended in a gas flow in an aero-dynamic levitator and heated with cw-CO2 laser. The temperature of the sample is monitored with a ratio pyrometer. When the desired temperature is reached, the levitator nozzle is split, the laser beam redirected to the beam dump and gas glow is shut with electromagnetic valves. Sample is dropped and caught with two plates. Its temperature is measured pyrometrically. The heat flow between the catcher plates and a water-cooled heat sink is measured with two semiconductor thermopiles. The advantages and pitfalls of the proposed design are discussed. This "drop and catch" calorimeter should be able to measure enthalpies related to phase transitions and melting, as well as obtain enthalpy increments from which heat capacities can be calculated.