scholarly journals Calcium phosphate bioceramics prepared from wet chemically precipitated powders

2010 ◽  
Vol 4 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Kristine Salma ◽  
Liga Berzina-Cimdina ◽  
Natalija Borodajenko
Keyword(s):  
Calcium Phosphate ◽  
Thermal Treatment ◽  
Calcium Hydroxide ◽  
Calcium Phosphates ◽  
Chemical Precipitation ◽  
Synthesis Temperature ◽  
Synthesis Product ◽  
Technological Parameters ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], ?-tricalcium phosphate [?-TCP] and HAp/?-TCP) by modified wet-chemical precipitation route. The ?-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300?C) HAp bioceramics with homogenous grainy microstructure, grain size up to 200-250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70?C and stabilizing ending pH at 9. .

Scale-Up of Wet Precipitation Calcium Phosphate Synthesis

2014 ◽  
Vol 604 ◽  
pp. 216-219 ◽  
Author(s):  
Marina Sokolova ◽  
Andris Putnins ◽  
Imants Kreicbergs ◽  
Janis Locs
Keyword(s):  
Calcium Phosphates ◽  
Scale Up ◽  
Chemical Precipitation ◽  
Pilot Scale ◽  
Precipitation Method ◽  
Technological Parameters ◽  
Wet Chemical ◽  
Pilot Scale Reactor ◽  
Scale Reactor ◽  
Wet Chemical Precipitation

Within current research calcium phosphates were synthesized by wet chemical precipitation method in laboratory and pilot scale reactor. The aim of this work was to study the influence of main technological parameters of wet chemical precipitation synthesis and scale-up of laboratory synthesis. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions such as hydroxyapatite (HAp), β-tricalcium phosphate (β-TCP) and biphasic calcium phosphates (HAp/β-TCP) in pilot scale reactor. Using the method developed it was possible to increase the product yield more than 30 times compared to formerly used laboratory scale method.

Preparation of F-Doped Hydroxyapatite via Wet-Chemical Precipitation Technique Combined with pH-Cycling

2015 ◽  
Vol 1117 ◽  
pp. 205-208
Author(s):  
V. Zalite ◽  
Karina Kostrjukova ◽  
Janis Locs
Keyword(s):  
Chemical Precipitation ◽  
Infrared Spectrometry ◽  
Technological Parameters ◽  
Substitution Level ◽  
Vis Spectroscopy ◽  
Ph Cycling ◽  
Ft Ir ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

F-doped hydroxyapatite (FHAp, Ca10(PO4)6OH2-xF2x) was synthesized by two step technology – wet-chemical precipitation and pH-cycling. Obtained powders were dried and calcined for further characterization. FHAp were analyzed by Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM) and UV-VIS spectrophotometry. FT-IR analysis approved fluoride incorporation into HAp structure, confirmed by OH...F bonding at 3546 and 745 cm-1. SEM microphotographs showed, that as-synthesized FHAp precipitates consist of needle-like crystallites. UV-VIS spectroscopy results were used for the determination of actual F- substitution level. After evaluation of results it was concluded, that fluoride substitution level in FHAp structure reached only x≤0.6. To perform higher substitution level, the technological parameters of the process need to be optimized.

Formation of Secondary Phases on Hydroxyapatite Powders for Bone Regeneration: Effect of Water Source

2008 ◽  
Vol 587-588 ◽  
pp. 37-41
Author(s):  
Vera Lourenço ◽  
Susana Dias ◽  
Carlos A. Nogueira ◽  
Fernando A. Costa Oliveira
Keyword(s):  
Water Source ◽  
Chemical Precipitation ◽  
Synthesis Temperature ◽  
Precipitation Method ◽  
Secondary Phases ◽  
Factors Affecting ◽  
Precipitation Medium ◽  
Wet Chemical ◽  
Regeneration Effect ◽  
Wet Chemical Precipitation

This study focus on the synthesis of Ca-deficient apatites (CDA) by using the wet chemical precipitation method in demineralised water solutions at pH=7 and synthesis temperature of 90 °C. Upon calcination at 1000°C, the resulting HAP powders decomposed leading to the formation of small amounts of β-TCP. Surprisingly, under some conditions, minor amounts of α- TCP were also formed at 1000°C together with β-TCP. The appearance of α-TCP is favoured by the absence of mineral ions in the precipitation medium, which in turn depends on the purity of the water used. Factors affecting the formation of both β-TCP and α-TCP are discussed.

scholarly journals Synthesis and Properties of Biphasic Calcium Phosphate Prepared by Different Methods

2014 ◽  
Vol 970 ◽  
pp. 20-25 ◽  
Author(s):  
Ahmad Nawawi Natasha ◽  
Ramesh Singh ◽  
Mohd Hamdi Bin Abd Shukor ◽  
Tan Chou Young ◽  
Judha Purbolaksono ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Dissolution Rate ◽  
Sol Gel ◽  
Chemical Precipitation ◽  
Phase Behaviour ◽  
Precipitation Method ◽  
Stable Phase ◽  
Profound Change ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

Hydroxapatite (HA) is a stable phase with low dissolution rate in body fluid. Meanwhile, β-tricalcium phosphate (β-TCP) is rather soluble but the dissolution rate is too fast for bone bonding. Therefore a mixture of both is desirable to control the bioresorbability. In this work, calcium phosphate powder has been synthesized via sol gel and wet precipitation method to compare phase behaviour of these powders upon calcination. XRD result clearly revealed that both as-synthesized powders were pure HA with good purity. The decomposition of HA to TCP took place in the range of 700-800 °C and 800-900 °C for sol gel and wet chemical precipitation powder, respectively. The weight loss detected at 700-850°C in TGA analysis confirmed the presence of this biphasic mixtures.From FTIR analysis, profound change in OH-band intensity was attributed to the increased in HA crystallinity with calcination temperature.

Nanostructured Calcium Phosphates for Biomedical Applications

2014 ◽  
Vol 604 ◽  
pp. 212-215 ◽  
Author(s):  
Linda Vecbiskena ◽  
Luigi de Nardo ◽  
Roberto Chiesa
Keyword(s):  
Phase Transformation ◽  
Biomedical Applications ◽  
Calcium Phosphates ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

This work is focused on the phase transformation from amorphous calcium phosphate (ACP) to nanostructured hydroxyapatite (HA) or tricalcium phosphate (TCP). Amorphous calcium phosphates with Ca/P molar ratio near 1.67 and 1.5 were synthesized by wet-chemical precipitation method and treated with ethanol. Upon thermal treatment, ACP clusters about 50 nm create a nanostructured HA or TCP. The highlights of this research: The precipitate treatment with ethanol provided a pure α-TCP that was found to be stable up to 1000 °C. HA is obtained from the ACP precursor synthesized using also ammonium dihydrogen phosphate.

scholarly journals Synthesis and characterization of nano-hydroxyapatite added with magnesium obtained by wet chemical precipitation

2021 ◽  
Author(s):  
Brandon A. Correa-Piña ◽  
Omar M. Gomez-Vazquez ◽  
Sandra M. Londoño-Restrepo ◽  
Luis F. Zubieta-Otero ◽  
Beatriz M. Millan-Malo ◽  
...  
Keyword(s):  
Chemical Precipitation ◽  
Synthesis And Characterization ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

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.

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