| At present, improving the implants biological effect of a new implant material by ceramic electroactive has become a hot spot. KBT powders has been synthesized by ammonium citrate sol-gel process was by hydrothermal and prepared natural copper/KBT lead-free piezoelectric ceramics at atmospheric pressure sintering. The phase composition and surface morphology of composite ceramic materials were characterized by XRD、SEM and EDS, material surface wettability tested with the contact angle tester, piezoelectric constant measured by quasistatic tester and the composites biological activity and antimicrobial properties were studied by simulating body fluid immersion test and antibacterial experiment.Natural copper/KBT piezoelectric ceramic obtained was characterized by XRD, SEM and other testing means and reached,KBT ceramic powders possesses perovskite structure and the grain size is evener at about 23μm. The impacts of sintering conditions on natural copper/KBT piezoelectric ceramics also were discussed, and concluded: exorbitant presintering temperature made samples hard to grid and higher sintering temperature could lead to melting phenomenon, so the best sintering temperature is 1030℃, presintering temperature 500℃, the heating rate of 2℃/min. Meanwhile, ceramic crystal has good crystalline, grain growth well, grain size and boundary clear; natural copper doped don’t change the natural copper/KBT ceramic perovskite structure, but the second phase BixFeyTizO3 x and Fe2O3 apear due to potassium ion volatilizing and iron ion gathering in the grain boundary in sintering process, ceramic grain size increasing then decreasing, grain shape from the needle transforming to the massive, the relative density ρr and piezoelectric constant d33 increasing and then decreasing and reaching maximum at the same time, respectively 27% and 31 PC/N when natural copper content is 3%. Natural copper dopant has "hard and soft" effect and combined action of many factors affect.Simulated body fluid immersion experiment proved that both the positive and negative sides of ceramic cathode surface have calcium phosphate salt deposition, but because of cathode surface more conducive to the adsorb Ca, P element in solution, which made more calcium phosphate salt generate on surfaced. Calcium phosphate salt deposition on natural copper/KBT piezoelectric ceramic cathode surface had relationship with immersion time, sintering temperature and natural copper content. With the increase of soaking time and sinter temperature, the more calcium phosphate salts deposited on ceramic surfaces. Calcium phosphate salt deposition on ceramic surface of increased and then decreased with the increase of natural copper content. In addition, the alcium phosphate salt deposition ccontent on the surface of samples after pretreatment by the many to the few order: HA pretreatment >dopamine pretreatment >CaSiO3 preprocessor>without pretreatment, which explained pretreatment can improve the biological activities of natural copper/KBT piezoelectric ceramic.The antibacterial activity of natural copper/KBT piezoelectric ceramic materials was tested by colony counting method, and the antibacterial mechanism discussed. The experimental results showed that the antimicrobial properties related to piezoelectric properties of ceramic. When natural copper content is 3%, ceramic maximum had piezoelectric constant, and antibacterial ratio also achieved maximum 98.35%. All the above, the natural copper/KBT piezoelectric ceramic has good biological compatibility and bone conductibility, which want to become a new bone defect repair replacement material with antimicrobial properties and has a broad potential application value and market prospect. |
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