应用钠β氧化铝测量Na-Pb合金的热力学性质
来源期刊:中国有色金属学报2000年第6期
论文作者:孙成文 陈深 杨芝洲
文章页码:877 - 881
关键词:钠β氧化铝; 固体电解质; 钠铅合金; 热力学函数
Key words:sodium beta-alumina; solid electrolyte; sodium-lead alloy; thermodynamic function
摘 要:应用 Na|Na+-β-Al2O3|NaxPb1-x固体电解质电池测定了42个Na/NaxPb1-x(x =0.043~0.987 8)电池在508~648 K的电动势。计算了钠/高铅钠合金(液,x =0.043~0.6)电池电动势及其温度系数, 钠在合金中的活度系数、 偏摩尔熵 - S(Na)、 偏摩尔焓-H (Na)和x(Na)的关系。 热力学函数对钠摩尔分数的线性关系,相应于在钠 铅相图中的富铅相界、共晶体NaPb4, NaPbNaPb3和化合物NaPb组分处产生的偏折,表征液态钠铅合金存在着类似于固相结构的化学络合物。根据电池电动势对组分和温度的关系,测量了合金的熔化温度及NaPb4, NaPbNaPb3, NaPbNa9Pb4的共晶温度。
Abstract: EMFs of fortytwo Na/NaxPb1-x (x=0.043 !33~0.987 8) cells were measured by using a Na|Na+ -β-Al2O3|NaxPb1-x solid electrolyte cell. The EMF and its temperature coefficient of the Na/NaxPb1-x (liquid), activity coefficient of the sodium in NaxPb1-x, sodium partial molar entropy - S (Na) and partial molar enthalpy -H (Na) were also calculated as a function of x (Na). For the liquid Na/NaxPb1-x cell, the linear relationship between dE/dT,- S (Na), -H (Na) and x(Na), respectively, were deflected at x(Na)= 0.083, 0.20, 0.39, 0.48, 0.52 which correspond to the rich lead phase, NaPb4 entectic point, NaPb-NaPb3entictic point and NaPb compound analogous to transformation of phase region inthe Na-Pb system. The results indicate that chemical complex exist in the molten NaxPb1-x near the temperature of liquids line in Na-Pb phase diagram. The moing temperatures of Na-Pb alloys and entectic temperatures of NaPb4, NaPb-NaPb3and NaPb-Na4Pb9 have been determined from the dependence of the cell EMFon component and temperature.