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研究了铁电极在中性Na_2SO_4溶液中恒电位阳极极化下。和在不同pH的H_2SO_4/Na_2SO_4溶液中腐蚀电位下的交流阻抗特性。当pH>3.5时,铁电极的界面电容急剧增大至10~3μF/cm~2数量级。而铁电极在中性Na_2SO_4溶液中的界面电容为铁电极上覆盖的Fe(OH)2的电容。通过恒电位阳极极化状态铁电极的高频和低频部份的阻抗特性分析,建立了阳极极化状态铁电极的等效电路。用交流阻抗计算了极化电流密度,其值与同样条件下测得的稳态电流密度相等,说明阳极极化状态下交流阻抗测定的适用性。
The ferroelectric polarization was investigated by potentiostatic anodic polarization in a neutral Na_2SO_4 solution. And the AC impedance under the corrosion potential of H_2SO_4 / Na_2SO_4 solution with different pH. When pH> 3.5, the interfacial capacitance of the iron electrode sharply increased to the order of 10 ~ 3μF / cm ~ 2. The interfacial capacitance of iron electrode in neutral Na_2SO_4 solution is the capacitance of Fe (OH) 2 covered by the iron electrode. By analyzing the impedance characteristics of the high frequency and low frequency parts of anodic polarization state ferroelectrics, an equivalent circuit of anodic polarization state ferroelectrics was established. The polarization current density was calculated by AC impedance, and its value was equal to the steady-state current density measured under the same conditions, indicating the applicability of AC impedance measurement under anodic polarization.