CaP Precipitation Under Piezoelectric Stimulation on ZnO/Ti

Calcium phosphate (CaP) formation under piezoelectric stimulation in vitro is investigated in this paper. Crystallized ZnO was synthesized hydrothermally on Ti-6Al-4 V pieces. The piezoelectric coefficient d33 was measured and found in the range of 2.1–3.7 pC/N. Tests of immersing ZnO/Ti sample in a flow-simulated body fluid under sonic stimulation were carried out. Different sonic excitation times (0.17 ~ 3 min) were set to assess the effect of excitation level. The results show that sphere-shaped CaP can be observed on the SEM photographs of excited and no-excited samples. The difference is aggregated CaP formed on excited samples, but not on no-excited. The effect of the excitation time on the shape of CaP is not obvious. The CaP formation on the electroconductive pasted samples shows the connection of aggregated CaP coat due to piezoelectric stimulation. More Ca and P contents in the CaP precipitate on acoustic excited sample than no-excited one were found. The crystallinity of CaP was found increased by the piezoelectric stimulation. We conclude that the sonic-stimulated piezoelectricity promotes electrical attraction between CaP clusters. It also promotes crystallization of the CaP during precipitation.