Isoperibolic calorimetry has been used for the first time to determine the mixing enthalpies of binary Nd–Ni liquid alloys in the range 0 < x Ni < 0.5 at 1733 K and range 0.55< x Ni < 1 at 1773 K. The binary Nd–Ni melts are characterized by significant negative mixing enthalpies with a minimum of –33.9 ± 0.8 kJ/mole at x Ni = 0.63 and 1750 K. In the temperature range studied (1733–1773 K), the mixing enthalpies of the melts are described by polynomial ΔH = x Ni (1 – x Ni )× × (–75.32 – 103.41 x Ni + 273.45 x Ni 2 $$ {x}_{Ni}^2 $$ – 817.02 x Ni 3 $$ {x}_{Ni}^3 $$ +548.58 x Ni 4 $$ {x}_{Ni}^4 $$ ). The ideal associated solution (IAS) model was used to calculate the activities of components, molar fractions of associates, Gibbs energies, and mixing entropies using our ΔH and Δ H ¯ i $$ \varDelta \overline{H}i $$ and literature data on the formation enthalpy of nickelides and the Nd–Ni phase diagram. All intermediate phases were considered stoichiometric, with zero excess heat capacity. Five associates were selected for the calculation: Nd 2 Ni, NdNi, NdNi 2 , NdNi 3 , and NdNi 5 . Most of them agree in composition with the intermetallides in this system. Only one of them does not exist in solid state. This is associate Nd 2 Ni, whose composition is close to that of the Nd 7 Ni 3 intermetallide. The activities of the Nd–Ni melt components show high negative deviations from ideal solutions. Associates of simplest composition, NdNi and NdNi 2 , are predominant in the melts. The mixing entropies of Nd–Ni liquid alloys are negative (minimum value is close to –6.4 J/mole · K). All our thermodynamic properties indicate that there is strong energy of interaction between Ni and Nd. The liquidus curves of the Nd–Ni system were calculated using the IAS model parameters.

中文翻译：

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Nd-Ni合金的热力学性质和相平衡

等周量热法首次用于确定二元 Nd-Ni 液态合金的混合焓，范围为 0 < x Ni < 0.5 at 1733 K 和范围 0.55< x Ni < 1 at 1773 K。 二元 Nd-Ni熔体的特征在于显着的负混合焓，在 x Ni = 0.63 和 1750 K 时最低为 –33.9 ± 0.8 kJ/mole。在研究的温度范围内 (1733–1773 K)，熔体的混合焓由多项式描述ΔH = x Ni (1 – x Ni )× × (–75.32 – 103.41 x Ni + 273.45 x Ni 2 $$ {x}_{Ni}^2 $$ – 817.02 x Ni 3 $$ {x}_{Ni }^3 $$ +548.58 x Ni 4 $$ {x}_{Ni}^4 $$ ）。理想的伴生溶液 (IAS) 模型用于计算组分的活度、缔合物的摩尔分数、吉布斯能、和混合熵使用我们的 ΔH 和 Δ H¯ i $$ \varDelta \overline{H}i $$ 以及有关镍化物形成焓和 Nd-Ni 相图的文献数据。所有中间相都被认为是化学计量的，具有零过剩热容。为计算选择了五位同事：Nd 2 Ni、NdNi、NdNi 2 、NdNi 3 和 NdNi 5 。它们中的大多数与该系统中的金属间化物在组成上一致。其中只有一种不以固态存在。这是伴生 Nd 2 Ni，其成分与 Nd 7 Ni 3 金属间化物的成分接近。Nd-Ni 熔体组分的活性显示出与理想溶液的高负偏差。成分最简单的伴生 NdNi 和 NdNi 2 在熔体中占主导地位。Nd-Ni 液态合金的混合熵为负值（最小值接近 –6.4 J/mole·K）。我们所有的热力学性质都表明 Ni 和 Nd 之间存在强大的相互作用能。使用 IAS 模型参数计算 Nd-Ni 系统的液相线曲线。