The system BaO-B2O3

Abstract

A phase equilibrium diagram of the system BaO-B20 3 has been constructed fr om data obtained essentiall y by the quenching method. Four congruently m elting compounds were identifi ed: BaOAB20 3, melting at 879 5 C; BaO.2B20 3, melting at 900 5 C; BaO.B20 3, melting at 1,095 5 C; and 3BaO.B20 3, melting at 1,383 5 C . Some optical properties of these compounds were determined with the petrographic microscope, and X-ray d.ffraction data suitable for their id entification were obtained. Barium m etaborate, BaO.B20 3, s howed an inversion occurring between 100 and 400 C. Mixtures contain ing less than 30 p ercent of BaO were found to eparate on fu sion into two li quid layers, one of which contained 30 p ercent of BaO, wherea t he other was nearly pure 1320 3 A curve showing indices of refraction of the quenched glasses is also presc ntcd.