Synthesis of calcium hydroxyapatite-tricalcium phosphate (HA-TCP) composite bioceramic powders and their sintering behavior

Kivrak, N
Tas, AC
Composite (biphasic) mixtures of two of the most important inorganic phases of synthetic bone applications-namely, calcium hydroxyapatite (Ca-10(PO4)(6)(OH)(2) (HA)) and tricalcium phosphate (Ca-3(PO4)(2) (TCP))-were prepared as submicrometer-sized, chemically homogeneous, and high-purity ceramic powders by using a novel, one-step chemical precipitation technique. Starting materials of calcium nitrate tetrahydrate and diammonium hydrogen phosphate salts that were dissolved in appropriate amounts in distilled water were used during powder precipitation runs. The composite bioceramic powders were prepared with compositions of 20%-90% HA (the balance being the TCP phase) with increments of 10%, The pellets prepared from the composite powders were sintered to almost full density in a dry air atmosphere at a temperature of similar to 1200 degrees C. Phase-evolution characteristics of the composite powders were studied via X-ray diffractometry as a function of temperature in the range of 1000 degrees-1300 degrees C, The sintering behavior of the composite bioceramics were observed by using scanning electron microscopy. Chemical analysis of the composite samples was performed by using the inductively coupled plasma-atomic emission spectroscopy technique.


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gamma-Fe2O3 (maghemite)-silica nanocomposite particles were synthesized using a sol-gel method. The condensation products of 3-glycidoxy propyltrimethoxy silane (GPTMS) and nitrilotriacetic acid (NTA) were introduced onto the surfaces of the gamma-Fe2O3 silica nanocomposite particles and subsequently, these modified surfaces were complexed with cobalt (Co+2) metal ions. A possibility of using these surface modified gamma-Fe2O3-silica particles for the purification of 6 x histidine tagged recombinant benzald...
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ULA, TA (American Geophysical Union (AGU), 1990-05-01)
Periodic (covariance) Stationarity conditions for multivariate periodic autoregressive moving average (PARMA) processes are investigated. It follows from a previous work that a necessary and sufficient condition for the periodic Stationarity of a multivariate periodic process is the (covariance) Stationarity of the “lumped” vector process which contains the periodic vectors as its elements. It is shown that for univariate and multivariate PARMA processes, even with periodically varying orders, the lumped pr...
Citation Formats
N. Kivrak and A. Tas, “Synthesis of calcium hydroxyapatite-tricalcium phosphate (HA-TCP) composite bioceramic powders and their sintering behavior,” JOURNAL OF THE AMERICAN CERAMIC SOCIETY, pp. 2245–2252, 1998, Accessed: 00, 2020. [Online]. Available: