Study On The TCP/TTCP Composite Bio-ceramics

With the development of science technology and medical concept updates, woundtreatment had also changed from traditional single grafts to tissue repair and functionalreconstruction which based on tissue engineering, biomaterials and composite grafts. As animportant scaffold materials for bone tissue engineering, composite calcium phosphatebio-ceramic materials had developed rapidly among high-tech industry because of itsexcellent biocompatibility, biological activity, security, well controllable degradation andosteogenesis. Composite calcium phosphate bio-ceramic has been the focus of biologicalceramics study.In this paper, TCP and TTCP were prepared via a chemical precipitation method by usingCa(NO3)2·4H2O and (NH4)2HPO4as raw materials. Then TCP/TTCP composite calciumphosphate bio-ceramic materials, which TCP and TTCP with equal molar ratio, were preparedby conventional sintering and microwave sintering on different temperature separately（1200℃、1250℃、1300℃）. The effects of sintering methods and sintering temperature on thecomposite calcium phosphate bio-ceramic materials were studied by shrinking percentage.The microstructure and morphology of the composite calcium phosphate bio-ceramicmaterials were studied by SEM and XRD. The biological activity of samples were researchedthrough simulation body fluid.The results show that with the increase of the intering temperature, the shrinkingpercentage and the density of both conventional sintering samples and microwave sinteringsamples were increase. Under the same temperature, the microwave sintering samplesshrinking percentage were higher than the conventional sintering samples. Experimentalresults show that the composite calcium phosphate bio-ceramic materials prepared bymicrowave sintering were better than that prepared by the conventional sintering, because ofmicrowave sintering own the superior of steady heating temperature field, small thermal stress,rapid heating rate, short sintering time and energy conservation.The results of XRD show that sintering temperature had effect on the HA crystalling ofthe composite calcium phosphate bio-ceramic materials. The HA could stably exist when the conventional sintering temperature reached1250℃or microwave sintering temperaturereached1200℃. When the two methods sintering temperatures further elevate, the HAbecame decomposed to TCP and TTCP. With the temperature further increase and time furtherextend, the decomposition contents of HA were increase. The results of SEM show that: thesamples, which after the conventional sintering, surface were uneven and the hole distributednon-uniform, but the samples, which after the microwave sintering, surface were compact andthe hole distributed uniform.Through the experiment of simulated body fluid soaking, it found a formation of densedeposits on calcium phosphate ceramics both prepared by conventional sintering andmicrowave sintering after two weeks. Analysis of XRD showed that it is hydroxyapatite layer.With the extension of soaking time, the particulatematter became larger and the layer becamedense. It also showed that the composite calcium phosphate bioceramics prepared bymicrowave sintering were more denser than that prepared by conventional sintering. The pHvalue of the samples both prepared by conventional sintering and microwave sinteringchanged scope (7.19~7.85) within safety limit that proved both the microwave sinteringsamples and conventional sintering samples possessed biological activity.