The System Bi₂O,—B₂O₃

Abstract

The phase diagram for the system Bi2O3‐B2O3 has been determined experimentally. The melting point of Bi2O3 has been redetermined as 825° C with an estimated overall uncertainty of about ±3°C, and the molal heat of fusion of Bi2O3, calculated from the slope of the liquidus curve, is 2050 cal per mole. The system contains a body‐centered cubic phase of approximate composition 12Bi2O3·B2O3, which melts incongruently at 632°C. Four congruently melting compounds exist in the system: 2Bi2O3· B2O3·5B2O3, Bi2O3·3B2O3, and Bi2O3·4B2O3, with melting points, respectively, of 675°, 722°, 708°, and 715°C. The Bi2O3·4B2O3 compound exhibits a sluggish transformation at 696°C. Compositions containing up to 97.5 wt% (85 mole %) Bi2O3 can be partly or totally quenched to glass. Indices of the quenched glasses are greater than 1.74. A region of liquid immiscibility extends at 709°C from almost pure B2O3 to 19.0 mole % Bi2O3. The extent of immiscibility theoretically calculated agrees with the experimentally determined value when 1.20 A is used for the ionic radius of Bi3+.

Synthesis of by the Flux Method

“…The transition of BiNbO 4 from the low-temperature orthorhombic phase to the high-temperature triclinic phase is well known to occur at 1293 K. An eutectic point is at 923 K at a molar ratio of Bi 2 O 3 : B 2 O 3 = 11 : 9 [18]. Figure 1 shows the XRD patterns for the products prepared at a low temperature by the flux method using Bi 2 O 3 -B 2 O 3 eutectic flux at 1073 K and by solid state reaction at 1173 K. These patterns agree with the pattern for BiNbO 4 reported in ICDD data 01-082-0348 [17].…”

Femtosecond nonlinear frequency conversion based on BiB3O6

“…Moh's hardness 5-6 [49,88,89] a 708°C in [90,91]; b slightly different parameters measured in [47,48] while the assignment in the preliminary work [92] seems different; c 4.897 g/cm 3 estimated in [47][48][49] by the buoyancy method; d measured in the 40-210°C range; e measurement from -100 to 300°C by dilatometry -the fits contain also quadratic terms, similar measurements in the 25-299.5°C range gave the values α11 = −26.43 × 10…”

Microwave synthesis of electrode materials for lithium batteries

“…The product was confirmed to be monophasic Bi 4 B 2 O 9 using X-ray diffraction (figure 5). In comparison, the conventional method (Levin and McDaniel 1962) is tedious and involves several intermittent grindings. The various electrode materials prepared by the microwave route and their preparative conditions are summarized in table 1.…”