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采用圆柱体状氧化锆基固体电解质原电池:(+)Pt|air|ZrO_2(MgO)|[O]_(Ag(1))|Ir(-),利用恒电压法测定了1473-1773 K银液中氧的扩散系数,通过外加恒电压后测定的电池外电路总电流,获得随时间变化的穿过固体电解质的氧离子电流,进而计算得到银液中氧的扩散系数.在假定符合Arrhenius公式的基础上,实验结果经最小二乘法处理确定的在1473-1773 K扩散系数与温度的关系为:D_O=(1.11±0.04)×10~(-3)exp(RT/-255373±1718).实验测得的银液中氧的扩散系数值与基于前人低温测定结果外推到本实验温度下的值比较接近.利用该公式计算得到1773 K下银液中氧的扩散系数Do=(1.96±0.28)×10~(-4) cm~2/s.

Recently liquid silver was usually used as the electrode for the research on the metallurgy with controlled oxygen flow by means of a galvanic cell employing solid oxygen-ion conducting electrolyte. The diffusivity of oxygen in liquid silver has a practical significance and theoretical value on understanding the kinetics process of electrochemical reaction with controlled oxygen flow. However, the predecessors' data for the oxygen diffusivities were generally below 1473 K and could not satisfy the requirements for the research on the metallurgy with controlled oxygen flow at higher temperatures. In the present study the diffusivities of oxygen in liquid silver in the temperature range of 1473 to 1773 K were determined by potentiostatic method, in which the cylindrical-like zir coma base solid electrolyte cell arrangement, (+)Ptlair|ZrO_2(MgO)|[O]_(Ag(1))|Ir(-), was employed. The diffusivity of oxygen (D_o) in liquid silver contained in a zirconia tube was calculated from the change of the external current with time by applying a preselected voltage on the electrochemical cell. On the assumption of Arrhenius equation, least square treatment of the results gave the following relation,D_O = (1.11± 0.04) ×10~(-3)exp(RT/-25573±1718), of which the confidence limit reached 95%. The present experimental results are in close agreement with those extrapolated from the data of other investigators at low temperature. The diffusivity of oxygen in liquid silver at 1773 K is (1.96±0.28)×10~(-4) cm~2/s.