Synthesis, Sintering And Properties Of Hydroxyapatite Based Composites

Hydroxyapatite [Ca10(PO4).(OH)2] HA is biomaterial that is used as bone scaffold and bone replacements of bone joints. When HA is used as bio implants, HA shows resorption in blood and poor mechanical properties such as fracture toughness and Vickers hardness as well. To overcome this drawback of HA, different compounds inorganic and organic compounds, polymers have been used with HA successfully. To improve the biocompatibility, in the light of collecting data this review has focused on the use of suitable inorganic and organic compounds and polymers with HA. The following combinations such as HA-Polymers with halides as functional group, HA-Polymers with hydroxyl group, HA-Silica and silicones, HAOrganometallic compounds, HA-Resins polymers, HA-Grignard's reagents can be used.Hydroxyapatite Ca10(PO4)6·OH2(HA) was sintered with the addition of 3 wt.% aluminum isopropoxide(C9H21Al O3) powder and 3 wt. % Teflon powder(-C2F2-). Sample was prepared by following sol-gel technique. Obtained pellets of samples were sintered. For investigation of effects of temperature on microstructures and mechanical properties the samples were sintered at various temperatures. For studying the phase composition, microstructures and elemental analysis the sintered samples were characterized by X-rays diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive X-rays diffraction(EDAX) respectively. After sintering the samples mechanical properties, i e, grains size, apparent density, Vickers hardness, bending strength and compressive strength were found to be 2.14-18.76 ?m, 1.523 6- 0.752 g/cm3, 3.60-0.600 GPa and bending strength 33.265 8-14.900 MPa, 75-33 MPa, respectively. As a result of sintering fluoridated composite material was obtained.In the present work fluoridation and densification of hydroxyapatite Ca10(PO4).(OH)2 [HA] was carried out. For this purpose hydroxyapatite powders was sintered with addition of fixed percentages of aluminum isopropoxide(C9H21Al O3) and different weight percentages of Ti F4. So fixed 4 wt % of aluminum isopropoxide and different wt. % of Ti F4 [5 wt%, 9 wt%, 13 wt%, 16 wt%, 19 wt%] were mixed with HA in aqueous solution. Through this work the effects of addition of aluminum oxide and Ti F4 were investigated. Obtained pellets of the specimens were sintered at 1250 °C temperature for 1 hour. To enhance the densification and mechanical properties of HA different amounts wt % of Ti F4 were used. Moreover composite biomaterial consist of oxides and fluorides of Aluminum(Al), Titanium(Ti) and Calcium(Ca) was obtained with fluoridated HA(HA-F) as well. In this work it was revealed that on adding 19 wt % of Ti F4 the obtained product was reached almost full densification and relative density was found 96.42%. Mechanical properties such as Vickers hardness and fracture toughness were improved by factors of 1.62 GPa and 35.88 Mpa-m1/2 respectively.Fluoridated composite Hydroxyapatite biomaterial was prepared by sintering the Hydroxyapatite Ca10(PO4)6.(OH)2 [HA] powder with addition of titanium fluoride 25 % wt.- Ti F3 and mixture of iron oxide and aluminum oxide [5 % wt.-Al2O3/Fe2O3;(5/1)]. The samples pellets were prepared by conventional sol-gel technique. The as-prepared samples were sintered at various temperatures and the effect of different temperature on grain size and mechanical properties has been investigated. The as-prepared samples were sintered at A-1100 °C, B- 1200 °C, C-1300 °C and sample(D) at 1400 °C. For exploration of phase composition the, grains size and elemental analysis the sintered sample pellets were characterizes by means of X-rays Diffraction(XRD), Field Emission Scanning Electron Microscopy(FESEM) and Energy dispersive Spectroscopy(EDS). After sintering, the sample's mechanical properties such as compressive strength, bending strength, Vickers hardness and bulk density were improved 43.8157 MPa-65.9320 MPa, 9.1357 MPa-43.8157 Mpa and 5.8876 GPa-10.8890 GPa and 1.5857 g/cm3-2.1426 g/cm3.Hydroxyapatite powder was sintered with addition of titanium fluoride Ti F3 powder and mixture powder of aluminum oxide/ Iron oxide powder. Aluminum oxide Al2O3 and Iron oxide Fe2O3 were mixed in ratio 5/1 wt %. For preparing sample(A) 5 wt % of this mixture(Al2O3/Fe2O3) was added to hydroxyapatite powder. For sample(B) Al2O3/Fe2O3-5 wt % and Titanium fluoride Ti F3-5 wt % was added to hydroxyapatite. For sample(C) Al2O3/Fe2O3-5 wt % and Titanium fluoride Ti F3-30 wt % was added to hydroxyapatite. Initially entire three samples were prepared by sol-gel technique. For investigation of role of sintering temperature on morphological structures and mechanical behaviors, the obtained samples pellets were sintered at various temperatures 1100 C, 1200 C, 1300 C, and finally 1400 C. For exploration of phase compositions the sintered samples were characterized by X-rays diffractions(XRD). For studying microstructures the sintered samples pellets were characterized by Field Emission Scanning Electron Microscopy(FESEM) and for elemental analysis Energy Dispersive Spectroscopy(EDS). Moreover for improving the mechanical properties the role of addition of various % of titanium fluoride Ti F3 to the sample was also studied. From the obtained results after sintering the samples it was revealed that addition of titanium fluoride was caused enhancing the mechanical properties of the samples.