Eiji Ichise

Nonstoichiometry of superconducting Ba2YCu3O7−y at temperatures between 870 and 1180 K

A thermogravimetric technique was employed for the determination of the nonstoichiometry of Ba2YCu3O7-y at temperatures between 870 and 1180 K and the oxygen partial pressure of 0.005 to 1 atm. The oxygen deficiency, y, varied from 0.8 to 1.3, corresponding to the presence of Cu2+ and Cu+ at the temperatures investigated.

A thermodynamic study of BaO + BaCl2 + Cr2O3 fluxes used for the removal of phosphorus from chromium-containing iron melts

Electrochemical measurements with solid-oxide galvanic cell of the type Mo/Mo + MoO2//ZrO2(MgO)//{Cu + Cr}alloy + (Cr2O3)slag/Mo were conducted at 1473 K in order to obtain the activities of Cr2O3 in BaO + BaCl2 + Cr2O3 slags used for dephosphorization of chromium-containing iron melts. Based on the activity measurements, it is concluded that in the system BaO + BaCl2 + Cr2O3 at 1473 K, there are 1 two-phase region in saturation with pure Cr2O3(s) and 3 three-phase regions. The activities of Cr2O3 within such three-phase regions decrease with an increase in BaO/BaCl2 mole ratios. The Cr2O3 activities in BaO + BaCl2 + Cr2O3 fluxes are, in general, greater than those in CaO + CaCl2 + Cr2O3, corresponding to much more effective dephosphorization by BaO + BaCl2 + Cr2O3 fluxes rather than CaO + CaCl2 + Cr2O3 slag.

A vapour pressure technique for the determination of the oxygen transport number of a solid oxide electrolyte

Abstract A combination of a solid-state electrochemical cell with a mass spectrometer has been used in the temperature range 800–1000°C to establish the oxygen ion transport number in yttria-doped zirconia and thoria. The technique involves the transfer of oxygen from a solid oxide electrode to a sample of liquid indium contained within a Knudsen cell made of the electrolyte. Indium oxide gas, In 2 O, is formed within the cell at a rate directly related to the oxygen ion flux into the liquid metal, and the flux of In 2 O out of the Knudsen orifice is calibrated from the known flux of indium atoms through the same orifice.