The major problems of seeding and growth of barium borate crystals in terms of new data on phase relations in BaO–B2O3–Na2O system

Natural differentiation of borate melt components and its influence on nucleation and growth of barium metaborate (BBO) crystals

“…On the other hand, polycondensated boron-oxygen associates act as the components of surface-active material and, hence, localize in the near-to-surface zone of melt and significantly complicate seeding and crystal growth in TSSG configuration (Fig. 1) [3]. In other words, these problems are indirect evidence of the high degree of anion polycondensation in melt or molten solution, which is confirmed by the tests of its solidification on the platinum rod.…”

“…Precision differential-thermal analysis (DTA) [3] and X-ray powder diffraction (X-rPD) method were used for investigation of crystallized samples. To interpret the X-rPD patterns, we used standard ones of corresponding compounds.…”

“…[3]), we reported the DTA results of the samples from the field of BBO primary crystallization of the ternary BaO-B 2 O 3 -Na 2 O system. The results indicated some ''lowtemperature'' phase transformations with absorption and, less often, with release of heat.…”

“…Addition of Na 2 O into melt leads to the growth of the LTTE amplitude on DTA curves. Previously we attributed LTTE to phase interactions (melting or crystallization), where one component is considerably enriched in boron oxide [3]. However, the works of our colleagues Meshalkin and Kaplun [5] allow assigning these effects to the reactions of solid-phase synthesis of the compound 2:3 at $610 1C and compound 2:1 above 720 1C (Fig.…”

General approaches to design of a reproducible technique for the growth of large crystals of barium metaborate (BBO) for industrial application

“…Our practice shows that this component increases the initial polycondensation degree of boron-oxygen component, especially in the near-to-surface zone of molten solution, which can complicate seeding and growth of crystals in the TSSG configuration ( Fig. 2) [5,6].…”