New microthermogravimetric apparatus for studying the kinetics of chemical diffusion in nonstoichiometric metal sulphides

Novel microthermogravimetric apparatus for studying the kinetics of metal-sulphur interactions and transport properties of transition metal sulphides, has been described. The main feature of this arrangement consists in the application of the carrier gas for sulphur vapour transportation and for protecting the balance chamber from sulphur attack. As a consequence, the helix balance, currently used in these equipments, could have been replaced by an automatic electronic microbalance resulting in two orders of magnitude higher accuracy of mass change measurements up to 10(-7) g. The application of two liquid sulphur reservoirs created very stable, strictly defined reaction conditions and enabled to make rapid changes of sulphur vapour pressure in the reaction chamber.