Na<SUB>2</SUB>O-B<SUB>2</SUB>O<SUB>3</SUB>-NiO系融体におけるNiOの活量および溶解度

Abstract

Activity and solubility of NiO in Na2O-B2O3-NiO melts were determined by use of EMF measurements of the following cell in the temperature range of 1123∼1373 K.(This article is not displayable. Please see full text pdf.) The results obtained are summarized as follows:(1) The activity coefficient (γ°NiO) of NiO in Na2O-B2O3-NiO melts indicates positive deviation from ideality. The values of γ°NiO obtained at 1298 K for the melts with 32.5, 48, and 60 mol%Na2O were 2.5, 6.2, and 3.2, respectively.(2) Solubility of NiO in Na2O-B2O3 melts was determined at the inflexion point on EMF vs NiO content curve and solubility lines of NiO in the Na2O-B2O3-NiO ternary system were estimated.The maximum content of NiO (=11 mol%NiO at 1373 K) was obtained at the composition of nearly 32.5 mol%Na2O.(3) Thermodynamic quantities of mixing of NiO were calculated by using the data of the melts containing 0.9 mol%NiO. Gibbs’s partial molar free energies of mixing of NiO were about −30∼40 kJ/mol at 1173 K and decreased with an increase in temperature and Na2O content.