交流阻抗谱研究钙磷陶瓷电沉积层的结构

用交流阻抗技术研究了不同电沉积时间的钙磷陶瓷沉积层。结果表明，沉积时间不同的陶瓷沉积层的交流阻抗谱存在显著的差别。采用双层结构物理模型，对不同沉积时间陶瓷沉积层的交流阻抗谱进行计算机拟合，得到的等效电路各元件拟合值显示：电极表面钙磷陶瓷为内密外疏型梯度沉积层。在陶瓷电沉积过程中，钙磷晶粒同时沉积于距电极表面不同距离的部位，沉积层厚度增加的同时内层密度也在逐渐增加，整个 只层的梯度结构处于动态变化之中。

STUDY ON STRUCTURE OF ELECTRODEPOSITION COATING OF CALCIUM PHOSPHATE CERAMICS BY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

The electrodeposition coatings of calcium phosphate ceramics(CPCs) prepared with various deposition times were studied by electrochemical impedance spectroscopy (EIS) measurements, the results show that there are significant differences among electrochemical impedance curves for electrodeposition coatings of CPCs obtained with various deposition times. The EIS spectra can be interpreted in terms of an "equivalent circuit" based on a two_layer mode of ceramic films with the circuit elements representing electrochemical properties of the electrodeposition coating, and the parameters obtained and their variation with the electrodeposition time indicate that the CPCs coating is of a gradient structure which consist of a compact inner layer and a sparse outer layer. CPCs particles are deposited in different location with the electrodeposition process, so both the thickness of the electrodeposition coating and the density of the electrodeposition inner increases and the whole gradient structure is in change with the electrodeposition time.