الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Calcium phosphate has been used in medical and dental applications for many years.Calcium phosphates has also been widely studied for bone defect and bone cement, dental defect filling, bone tissue engineering and drug delivery applications.Calcium phosphate has also crystal structure quite similar to the natural bone. Accordingly it is compatible and active with the natural bone. However, their low strength and their high brittleness prohibited their use in many stress-bearing locations, which would require an improvement in mechanical properties. Nano Calcium phosphates has been synthesized employing coprecipitationtechnique.Nano Calcium phosphates has been studied by X-Ray Diffraction (XRD) to explore the structural features. The crystallite size less than 7 nm was obtained from X-ray. Scanning electron microscopy (SEM) and XRF techniques were utilized to confirm the structure, microstructure and stoichiometry of the prepared Nano Calcium phosphates. FT-IR is used to identify chemicals bonds and molecular structures of the Nanocomposite Calcium Phosphate. Differential scanning calorimetry (DSC) and TheThermogravimetric analysis (TGA) were used to study the thermal transitions of Nano Calcium Phosphate, thermal stability, chemical decomposition or vaporization, and sublimation of the sample at higher temperatures. There was no phase transformation taking place upon heating. such results clearly indicate that the prepared powder has excellent thermal stability even at high temperature. To characterize the nanocalcium phosphate, the electrical conductivity AC and dielectric constants were measured against temperature over a wide range of frequency from 50 Hz up to 5 MHz. Mechanical properties of calcium phosphate have been measured by Ultrasonic pulse technique. The elastic constants of Calcium Phosphate nanocomposite were calculated by measuring densities, Longitudinal velocitiesVl and ShearvelocitiesVsh of ultrasound waves at room temperature.It has been found that the elastic constants of calcium phosphate and natural Bone in the same range. Computed Tomography (CT) measurements for Region of Interest (ROI) as indication of density, using X-ray attenuation, have been used to study the effect of Radiation exposure to Gamma Ray on nanocalcium phosphate. After the exposure to γ-rays, thedensity increases and decreases again with time. This increase and decrease with time has been attributed to destroy the weakest bond.