phase diagrams

A study of the solubility in the ternary systems NaOH-NaBO,-H,O and КОН-КВО,-Н.О is of special interest from a fundamental and practical point of view. These systems represent the discharged products of the borohydrides fuel cells. The performance of such mixtures is determined by the solubility of their components. Therefore, in the present work the solubility in the ternary systems was studied by means of isothermal saturation within 10+50°C.

The division of the four-component reciprocal system Na⁺, Rb⁺, Cs⁺ || F⁻, NO₃⁻ into stable elements was carried out for the first time. The phase tree, confirmed by the experimental data from the differential thermal analysis, was constructed. The chemical interaction in a yet unexplored faceting element, i. e. in the three-component reciprocal system Na⁺, Cs⁺ || F⁻, NO₃⁻, and in the four-component reciprocal system was studied.

A study of the solubility in the ternary systems NaBH₄–NaOH–H₂O, KBH₄–KOH–H₂O, NaOH–NaBO₂–H₂O и KOH–KBO₂–H₂O is of special fundamental and practical interest. The first two systems are used as a fuel and as a hydrogen source in hydrogen power engineering that includes the low-temperature fuel cells; borohydrides are converted into metaborates. Hence, the last two systems represent the discharged by-product.