磷酸钙骨水泥水化过程的交流阻抗特性

A C IMPEDANCE SPECTROSCOPY IN THE HYDRATION PROCESS OF CALCIUM PHOSPHATE CEMENT

研究了磷酸钙骨水泥水化硬化过程的交流阻抗行为．结果表明：不同水化时间样品的交流阻抗谱在低频区是相互平行的，与实轴的交点值先增大，水化４ｈ后开始减少，表明在水化开始阶段由于水化产物的形成而使Ｐ·ｒ０（孔隙率与平均孔径的乘积）值减小，４ｈ以后，随着水化的进行，Ｐ·ｒ０值不但不降低，反而有所升高．实验结果还表明：固液比越大，交流阻抗谱直线同实轴的交点值越大；不同颗粒配比的样品其阻抗谱有所不同，水化２４ｈ后，小颗粒配比的样品的Ｐ·ｒ０值最小，而大颗粒配比的样品的Ｐ·ｒ０值最大；固化液质量分数对交流阻抗谱影响很大，其阻抗谱由孔中溶液浓度和Ｐ·ｒ０值共同决定；晶种的质量分数不同，交流阻抗谱的变化规律也不同，同时随水化时间的进行，阻抗谱也会发生变化．

In this paper, A C impedance behavior of calcium phosphate cement system in the hydration process is investigated. The results show that the curves of an impedance spectrum at low frequency in different hydration periods are linear and parallel. The values of the intersection between the spcetrum and the real axis increase initially, and then decrease after 4h hydration, which indicates that the values of P·r 0(porosity×mean pore size )decrease due to the formation of hydration products;but after 4h of hydration, the P·r 0 value increases in stead of decreasing. The results also indicate that the bigger the ratio of particle to water, the higher the value of the intersection between the spectrum and the real axis. The impedance spectra are different with the various mixes of particles. After 24h hydration, the value of P·r 0 for the samples is the minimum, which are the smallest particle mix, while for P·r 0 value is the maximum, which is the largest particle. The mass fraction of solution greatly affects the A C impedance behavior, which is determined by P·r 0 and the concentration of pore solution. When the mass fraction of crystal seed is changed, the impedance spectrum is also changed, and the impedance behavior is also different at different hydration periods.