Application of the torsion technique for the measurement of vapour pressures in the temperature range 1500-2500 C

Abstract

A metal apparatus is described for the measurement of vapour pressures under equilibrium conditions between 10-7 and 10-4 atm, approximately, and free evaporation conditions between 10-9 and 10-4 atm approximately. The torsion method is employed in two variations to make these measurements. The upper limit of temperature of operation which has so far been attained has been 2500°C, and the instrumental reasons which cause this limitation are discussed. The apparatus has been used to obtain fairly accurate vapour pressures of liquid platinum under equilibrium conditions and solid platinum and thoria under conditions of free evaporation.