Sintering of Hydroxyapatite Ceramic Produced by Wet Chemical Method

2011 ◽  
Vol 264-265 ◽  
pp. 1856-1861 ◽  
Author(s):  
Ramesh Singh ◽  
R. Tolouei ◽  
Chou Yong Tan ◽  
K.L. Aw ◽  
Wei Hong Yeo ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Maximum Hardness ◽  
Wet Chemical Method ◽  
Hydroxyapatite Ceramic ◽  
Maximum Value ◽  
Wet Chemical ◽  
Increasing Temperature

In the present work, densification of synthesised hydroxyapatite (HA) bioceramic prepared via chemical precipitation method was investigated. HA samples was prepared by compaction at 200 MPa and sintered at temperatures ranging from 800°C to 1400°C. The results revealed that the HA phase was stable for up to sintering temperature of 1250°C. However, decomposition of HA was observed in samples sintered at 1300°C with the formation of tetra-calcium phosphate (TTCP) and CaO. Samples sintered above 1400°C were found to melt into glassy phases. The bulk density increases with increasing temperature and attained a maximum value of 3.14 gcm-3 at 1150°C whereas maximum hardness value of 6.64 GPa was measured in HA sintered at 1050°C. These results are discussed in terms of the role of grain size.

Synthesis, Sintering and Microstructural Characterization of Nanocrystalline Hydroxyapatite Composites

2004 ◽  
Vol 845 ◽  
Author(s):  
B. Viswanath ◽  
N. Ravishankar ◽  
Suprabha Nayar ◽  
Arvind Sinha
Keyword(s):  
Mechanical Properties ◽  
Chemical Method ◽  
Sintering Temperature ◽  
Microstructural Characterization ◽  
Wet Chemical Method ◽  
Maximum Value ◽  
Nanocrystalline Hydroxyapatite ◽  
Wet Chemical ◽  
Nanocrystalline Alumina

ABSTRACTNanocrystalline hydroxyapatite (HAp) exhibits better bioactivity and biocompatibility with enhanced mechanical properties compared to the microcrystalline counterpart. In the present work, nanocrystalline hydroxyapatite was synthesized by wet chemical method. Sintering was carried out with nanocrystalline alumina as additive, the content of alumina being varied from 10 to 30 wt% in the composite. For 20 and 30 wt % Al2O3, hydroxyapatite decomposed into tricalcium phosphate (TCP) above the sintering temperature of 1100°C. The fracture toughness of nano HAp-nano Al2O3 composite is anisotropic in nature and reached a maximum value of 6.9 MPa m1/2.

Effect of Nano Silica on the Sinterability of Hydroxyapatite Dense Bodies

2011 ◽  
Vol 264-265 ◽  
pp. 1832-1838 ◽  
Author(s):  
R. Tolouei ◽  
Chou Yong Tan ◽  
Ramesh Singh ◽  
Iis Sopyan ◽  
Wan Dung Teng
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Nano Silica ◽  
Dense Bodies ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

The effects of adding a small amount of nano silica in hydroxyapatite (HA) on the sinterability and mechanical properties of hydroxyapatite were studied. The starting HA powder was synthesized using a novel wet chemical precipitation method. Different amount of silica powder was mechanically mixed with the synthesized HA. The green samples were subsequently cold isostatically pressed at 200 MPa. Sintering in air was accomplished by firing the green samples at temperatures ranging from 1050°C to 1250°C. Sintered samples were analyzed to determine phase composition and mechanical properties. The XRD analysis revealed that with increasing the amount of silica in the HA powder, decomposition of HA to TCP occurred at sintering temperature higher than 1050°C. The bulk density of all silica-doped samples decreased through the temperature range studied. In agreement with the bulk density trend, the increasing silica additives in HA depleted the Young’s modulus and Vickers hardness of the HA body. The study revealed that the addition of silica have an adverse effect on the sintered properties of hydroxyapatite bioceramics.

Synthesis and Structural Characterization of Zinc and Magnesium Doped Hydroxyapatite

2012 ◽  
Vol 531-532 ◽  
pp. 250-253 ◽  
Author(s):  
Hong Quan Zhang ◽  
Ming Zhang ◽  
Lu Wei Fu ◽  
Yu Ning Cheng
Keyword(s):  
Hydrothermal Treatment ◽  
Structural Characterization ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Starting Solution ◽  
Wet Chemical ◽  
Zn Ions ◽  
Wet Chemical Precipitation ◽  
Surface Of Crystals

Zn or Mg ions doped hydroxyapatite (HA) particles were successfully developed by introducing various concentration of Zn or Mg in the starting solution using wet chemical precipitation method and followed a hydrothermal treatment. The products were identified as HA by XRD and FTIR, and the precipitated particles had a rod-like morphology. All the products for Mg and Zn ions concentration in the preparation solution less than 40 mol% were identified as HA. Substitution of Mg and Zn in HA crystal would impair the crystallization of HA and significantly reduce the length of a, c values of HA unit cell, which clearly demonstrated that Mg or Zn ions were structurally incorporated into the apatite crystals, they were not just absorbed on the surface of crystals.

scholarly journals Sintering behavior and property of bioglass modified HA-Al2O3 composite

2012 ◽  
Vol 44 (3) ◽  
pp. 265-270
Author(s):  
Li-li Wang ◽  
Xiu-Feng Wang ◽  
Xu Ding ◽  
Jian-feng Zhu
Keyword(s):  
Production Cost ◽  
Chemical Method ◽  
Sintering Temperature ◽  
Volume Density ◽  
Sintering Behavior ◽  
Wet Chemical Method ◽  
Al2o3 Composite ◽  
Wet Chemical ◽  
Different Content ◽  
Sintered Temperature

The bioglass modified HA-Al2O3 composites were successfully fabricated by mixing HA, synthesized by wet chemical method between precursor materials H3PO4 and Ca(OH)2, with 25wt% Al2O3 and different content of bioglass (5%, 25%, 45%, 65wt%) respectively, with a mole fraction of 53.9%SiO2, 22.6%Na2O, 21.8%CaO, and 1.7wt%P2O5, sintered in air at various temperatures (750-950?C) for 2h. when the content of bioglass is below 45wt% in the composite, HA decomposes completely and transforms to ?-TCP. The main phase in this case are ?-TCP, Al2O3 and Ca3(AlO3)2.When the content of bioglass is above 45wt% in the composite, the decomposition of HA to ?-TCP is suppressed and the main phases in this case are Al2O3 and HA, DCP?CaHPO4? and ?-TCP, which almost have the same chemical composition, forming ternary-glass phase, and have better bioactive than pure HA. It can also be found that at the certain addition of bioglass, the higher sintered temperature, the bigger volume density and flexural strength of the composite are, but when the sintered temperature reaches 950?C, they decrease. This modified HA-Al2O3 composites by calcium silicate glass have a much lower sintering temperature and decrease the production cost much.

Effects of Powder Synthesis Method on the Sinterability of Hydroxyapatite

2011 ◽  
Vol 264-265 ◽  
pp. 1538-1544 ◽  
Author(s):  
K.L. Aw ◽  
R. Tolouei ◽  
Ramesh Singh ◽  
Chou Yong Tan ◽  
Wei Hong Yeo ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Sintering Temperature ◽  
Synthesis Method ◽  
Theoretical Density ◽  
Wet Chemical Method ◽  
Powder Synthesis ◽  
Temperature Range ◽  
Increasing Trend ◽  
Wet Chemical ◽  
Better Than

The sinterability of hydroxyapatite (HA) powder synthesized through a novel wet chemical method (HAp) and a wet mechanochemical method (HAwm) was investigated over a temperature range of 1000oC to 1400oC in terms of phase stability, bulk density, hardness and fracture toughness. The results indicated that the sinterability of HAp powder were significantly better than HAwm powder. Moreover, the XRD traces of HAwm sintered samples showed signs of decomposition into TTCP when sintered at 1300oC and above. Densification of ~98% of theoretical density was attained by HAp compacts at 1100oC while the HAwm compacts exhibited only ~96% of theoretical density even at 1350oC with no significant increase of density at 1400oC. The Vickers hardness of HAp showed increasing trend for temperature range of 1000oC to 1100oC with the compacts attaining HV of ~7 GPa at 1100oC. Subsequently, the hardness decreased with increasing sintering temperature though the value does not dropped below ~5 GPa. Similarly, HAwm compacts showed an increasing trend from 1000oC to 1300oC with the largest HV attained was ~4.57 GPa. Further increased in sintering temperature resulted in the decreased of Vicker’s hardness. Moreover, the HAp samples reached a maximum fracture toughness of ~0.9 MPam1/2 at 1050oC while the HAwm attained maximum KIc of only ~0.7 MPam1/2 at 1300oC.

scholarly journals Far-infrared optical constants of ZnO and ZnO/Ag nanostructures

RSC Advances ◽  
2014 ◽  
Vol 4 (40) ◽  
pp. 20902-20908 ◽  
Author(s):  
Reza Zamiri ◽  
Avito Rebelo ◽  
Golriz Zamiri ◽  
Atena Adnani ◽  
Ajay Kuashal ◽  
...  
Keyword(s):  
Optical Constants ◽  
Far Infrared ◽  
Cost Effective ◽  
Chemical Precipitation ◽  
Chemical Precipitation Method ◽  
Precipitation Method ◽  
Ag Nanoparticle ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

We report on the synthesis of ZnO nanoplates and ZnO nanoplate/Ag nanoparticle heterostructures via a simple and cost effective wet chemical precipitation method.

Electrophoretic Deposition of Hydroxyapatite Nano Coating on Etched Titanium Surface

2005 ◽  
Vol 288-289 ◽  
pp. 183-186 ◽  
Author(s):  
F. Chen ◽  
L.W. Lin ◽  
Chang Jian Lin ◽  
W.W. Lu
Keyword(s):  
Mechanical Properties ◽  
Electrophoretic Deposition ◽  
Chemical Method ◽  
Titanium Surface ◽  
Sintering Temperature ◽  
Deposition Process ◽  
Wet Chemical Method ◽  
Nano Structure ◽  
Nano Coating ◽  
Wet Chemical

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) is biocompatible and bioactive, however, it is relatively brittle. The development of HAp coatings on medical metal surface is a good way to improve the mechanical properties of HAp. In the present study, a HAp coating with nano-structure on a roughened titanium surface was developed by electrophoretic deposition process. To decrease sintering temperature HAp nanoparticles synthesized by a wet chemical method was used. It was observed that the coating was uniform and showed no cracks. After sintering the HAp coating still remained nano structured. The surface treatment of Ti was applied to form a distribution of small pits and a TiO2 thin layer on the Ti surface that improves the adhesion of coating to the Ti substrate. It was shown that the bonding strength of coating was 18 ± 2.5MPa. The hardness and Young’s modulus were 40.6 and 0.42 GPa, respectively.

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