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.

Manufacturing of High Toughness Hydroxyapatite Produced by Wet Chemical Method

2011 ◽  
Vol 110-116 ◽  
pp. 1289-1295
Author(s):  
Ranna Tolouei ◽  
Singh Ramesh ◽  
Chou Yong Tan ◽  
Meenaloshini Satgunam ◽  
Mahdi Amiriyan
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Ceramic Materials ◽  
Xrd Analysis ◽  
Chemical Precipitation ◽  
Holding Time ◽  
Precipitation Method ◽  
Tissue Replacement ◽  
Wet Chemical ◽  
Heating Profile

Hydroxyapatite (HA) is among the leading ceramic materials for hard tissue replacement implants. Despite the excellent bioactivity of HA, low toughness has limited the application of these materials to non-load bearing areas. The sinterability of nanocrystalline hydroxyapatite (HA) powder via new heating profile for conventional pressureless sintering was studied. The starting nanocrystalline HA powder was synthesized by wet chemical precipitation method. After uniaxial pressing followed by isostatic pressing, HA powder compacts are sintered over the temperature range of 1000°C to 1300°C. Different holding time of 1 minute and 120 minutes was applied as a heating profile of HA samples. The results revealed that new heating profile was effective in producing a HA body with high density of 98% when sintered at 1200°C. Subsequently, mechanical properties such as fracture toughness and hardness, of HA compacts increased with decrease in grain size. HA showed the highest hardness of 9.51 GPa and fracture toughness of 1.41 MPa.m1/2 when sintered at 1100 °C. XRD analysis indicated that decomposition of HA phase during sintering at high temperatures do not occur. Short holding time leads to finer microstructure of HA and subsequently better mechanical properties.

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 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.

scholarly journals Sinterability of Magnesium Hydroxyapatite Bioceramic and Its Mechanical Properties

2018 ◽  
Vol 7 (3.11) ◽  
pp. 197
Author(s):  
Syakir Ramli ◽  
Mardziah Che Murad ◽  
Nik Rozlin Nik Masdek
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Compressive Strength ◽  
Organic Compounds ◽  
Sintering Temperature ◽  
Precipitation Method ◽  
Artificial Bone ◽  
Lower Strength ◽  
Similar Composition ◽  
Dense Bodies

One of the most favoured material in bone tissue engineering field nowadays is hydroxyapatite (HA), which is also known to be bioactive and has a similar composition to human bone. However, developing an artificial bone or bone graft using biocompatible HA is a challenging task due to the lower strength of the main substance. To improve the mechanical properties of synthetic HA, introduction of metallic substance such as magnesium (Mg) into HA has been proposed. In this present study, 0, 10 15 wt% of magnesium hydroxyapatite (MgHA) nanopowders were prepared by a simple wet precipitation method. These nanopowders were then compacted using a 10-ton compression uniaxial press machine with 150 MPa pressure to form a disc shape of dense MgHA. After that, the MgHA discs were sintered at a temperature of 1000 °C and 1100 °C to remove the organic compounds and further densify the ceramics. XRD results showed that the crystallinity of MgHA increased when the sintering temperature increases. The compression test showed that the 10 wt% MgHA sample recorded the highest compressive strength (243.59 MPa) when sintered at 1100 °C, while pure HA has the lowest value with 49.37 MPa. This study also demonstrates that sintering temperature at 1100 °C gives significant improvement to the mechanical properties of the MgHA dense bodies compared to sintering at 1000 °C.  

Evaluation of Sr- and/or Mg-Containing Hydroxyapatite Behavior in Simulated Body Fluid

2014 ◽  
Vol 631 ◽  
pp. 61-66 ◽  
Author(s):  
Liga Stipniece ◽  
Kristine Salma-Ancane ◽  
Andris Putnins ◽  
Liga Berzina-Cimdina
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Apatite Formation ◽  
Particle Sizes ◽  
Chemical Phase ◽  
Ca Ions ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

The main goal of this study was to evaluate the behavior of Sr- and/or Mg-containing hydroxyapatite (HAp) bioceramics in simulated body fluid (SBF). Sr-and/or Mg-containing HAp powders were synthesized by modified wet chemical precipitation method. Sr-and/or Mg-containing HAp bioceramics were prepared by uniaxial pressing of the precipitated powders and subsequent sintering at 1100 °C for 1 h. The synthesis products were characterized in terms of chemical, phase and molecular composition. Influence of the substitutions on thermal stability, morphology and microstructure of the HAp products were evaluated. Results suggest that incorporation of Sr (up to 1.45 wt.%) in HAp structure induced an increasing of particle sizes, but incorporation of Mg (up to 1.05 wt.%) led to a reduction of particle sizes of the HAp powders. The ability to simultaneously release bioactive ions and the apatite-formation ability of the Sr-and/or Mg-containing HAp bioceramics were evaluated through immersing the samples in SBF for different time periods. Ca ions release and apatite-formation ability on the surfaces of the Sr-and/or Mg-containing HAp bioceramics in SBF depends on Sr and/or Mg concentration in the samples.

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.

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