الفهرس 
Hydroxyapatite based ceramic compositesOnly 14 pages are availabe for public view
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Abstract
Millions of tons of eggshell biowaste materials are generated around the world with huge amounts,
causing serious problems in the environment. Although these wastes contain valuable minerals, their
use is not widespread. The present work aims at the utilization of henʼs eggshell biowaste in
production of pure nano hydroxyapatite powder used in biomedical applications. characterization of
the prepared powder was carried out using X-ray diffraction (XRD), thermal gravimetric analysis
(TGA), infrared spectoscopy (IR) and transmission electron microscopy (TEM) techniques. The results
showed that the prepared powder is composed of pure hydroxyapatite with a particle size ranging
between 35 and 122 nm.
The prepared nano hydroxyapatite powder was used to prepare: porous, dense and composite ceramic
bodies that investigated for their phase composition, microstructure, physical and mechanical
properties, and bioactivity.
The results revealed that:
• Porous HA scaffolds prepared via polymeric sponge method calcined at 1250°C for 2 h possess high
porosity with interconnected pores structure. The studied scaffolds showed suitable mechanical
strength necessary for bone tissue engineering. Thin film XRD, SEM and EDS confirmed the presence
of a rich bone-like apatite layer on the scaffold’s surface post immersion in SBF. The
biodegradability test indicated that the HA scaffolds has the ability to degradable naturally with
the time.
• Coating of porous HA scaffolds with 1.5% w/v CMC by infiltration method led to the
improvement of mechanical
properties. The biological results revealed that the coated bodies have excellent bioactivity as
well as biodegradability.
• Dense HA scaffolds with relative density 96.95% and low porosity were prepared by uniaxial
pressing. Bioactivity measurements, in vitro test confirmed the presence of apatite layer on the
dense HA bodies surface after 28 days immersion in SBF solution. It was noticed that after 28 days
the solubility of the HA is not more than 1.08%.
• When ZTA was added to HA both the compressive strength and the three point bending strength
increased up to 20 mass-
% ZTA addition. This is due to the preserved ZrO2-Al2O3 particles present in the composition. HAZ20
composite bodies show the highest compressive and three point bending strengths. SEM and EDX
results of HAZ20 composite bodies confirmed the excellent bioactivity of their bodies. It was found
that the rate of the weight loss of the HAZ20 composite bodies was 0.4% during the soaking time up
to 28 days.