Study On The Preparation Of Hydroxyapatite Materials And Their Properties

In this paper, pure HAP and doped HAP powder were prepared by sol-gel method, hydrothermal method and microwave-assisted micro-emulsion method, respectively. The chemical composition, reaction process and fluorescence character of solution phase, precursor powder, pure HAP, and doped HAP were all studied by SEM, TEM, PTIR, XPS, ICP, XRD, and so on. On the other hand, the as-synthesized HAP powder was calcined to obtain HAP ceramic. The effect of the component and technology factor on the phase composition, high-temperature thermal decomposition, microstructure, bending strength and fracture toughness of pure HAP, HAP-B2O3 and HAP-B2O3-ZrO2 was investigated systematically, including annealing temperature and chemical composition. Finally, the biocompatibility of B2O3-ZrO2-HAP ceramic composites was also explored through SEM, EDS, FTIR.HAP nanoparticles with pure phase were synthesized by sol-gel method. The results show that, with the increasing of the synthesis temperature, the purity of HAP showed a rising trend and the average particle size of the powder also increased gradually. The purity of powder is the highest when the temperature is 600-700℃, and the average particle size is about 50-60nm.HAP crystals doped with Eu3+and Tb3+which were synthesized through hydrothermal method doesn't need to calcine. It has been shown that the obtained phosphors have a uniform rod-like morphology, nano-scale and narrow size distributiion. Eu:HAP and Tb:HAP phosphors show the characteristic emission peak of Eu3+and Tb3+, and the decay curves of the two samples are consistent with double-exponential function. Moreover, the fluorescence intensity of samples rises with the increasing of the solvent thermal reaction temerature, and the best doping concentration of Eu3+and Tb3+in Ln:HAP is 5%. Eu:HAP particles with fluorescence character were synthesized by microwave-assisted micro-emulsion, and the reaction process is carried out under mild conditions. The results showed that the synthesized Eu:HAP particles have high purity and crystallinity, and the characteristic emission spectra of Eu3+is bright red fluorescence. The decay curves are agreed with double-exponential function. The morphology and particle size of production are determined by PH of initial solution.The preparation technology shows that pure HAP occurred high-temperature thermal decomposition and gotβ-TCP when sintering temperature rising from 1200℃to 1350℃. With the rising of sinter temperature the decomposition is increaseed, so the value of bending strength and fracture toughness is decreased. But when B2O3 was added, the high-temperature thermal stability of HAP is improved. Sintered at 1250℃for 2h, the content of B2O3 is 5wt%, and the bending strength and fracture toughness of B2O3-HAP composite materials is 103MPa and 0.65MPa·m1/2, respectively. However, the addition of ZrO2 has small impact on the high-temperature decomposition. Sintered at 1350℃, the values of bending strength and fracture toughness get to the maximum,122 MPa and 1.58 MPa·m1/2 respectively.The study on biocompatibility shows that immersed in SBF for different time the microstructure of B2O3-ZrO2-HAP composite ceramics is different. It mainly due to the amorphous hydroxy-patite particles deposited on the surface of the specimen in the process. There are three stages in the growth process of the nucleation of ACP. The first stage is the erosion of surface of B2O3-ZrO2-HAP by SBF. The second stage is ion-exchange which occurred between B2O3-ZrO2-HAP and SBF. The last stage is the formation process of the stable ACP. Bio-acute toxicity showed that if the B2O3-ZrO2-HAP ceramic powder was injected into rabbits, then felt normally for 72h, there is no death or convulsions, paralysis and respiratory depression and other adverse reactions.