EFFECT OF SEVERAL CALCINATION TEMPERATURE ON DIFFERENT CONCENTRATION ZINC SUBSTITUTED CALCIUM PHOSPHATE CERAMICS

2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Mohamad Firdaus Abdul Wahid ◽  
Koay Mei Hyie ◽  
C. M. Mardziah ◽  
N. R. Nik Roselina
Keyword(s):  
Calcium Phosphate ◽  
Calcination Temperature ◽  
Zinc Concentration ◽  
Calcium Nitrate ◽  
Zinc Nitrate ◽  
Precipitation Method ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Calcium Phosphate Ceramics ◽  
Phosphate Solutions

Zinc substituted calcium phosphate ceramics powders were produced from precipitation method using calcium nitrate, zinc nitrate and ammonium dihydrogen phosphate solutions. Several zinc ions concentrations (5, 10, and 15 mole %) were substituted into calcium phosphate ceramics with the (Ca+Zn)/P initial ratio were set to 1.67. Calcium phosphate powders were then calcined at 600, 700, 800, 900, and 1000°C to observe its effect on the material phase behavior. By increasing the calcination temperature, XRD peaks changed from broad to narrower shape indicating that the powders are highly crystalline. Hydroxyapatite (HA) partly transformed to another phase which is tricalcium phosphate (β-TCP) at 700°C confirming the formation of biphasic calcium phosphate ceramics. FESEM observations clearly exhibit that the particles are in nanosized scale which explains why as zinc concentration increases, the particles tend to be agglomerated.

Synthesis and Phase Transformation of Calcium Phosphate Prepared from Chicken Eggshells and Ammonium Phosphate

2011 ◽  
Vol 214 ◽  
pp. 182-186
Author(s):  
Piyapong Pankaew ◽  
Ekachai Hoonnivathana ◽  
Pichet Limsuwan ◽  
Kittisakchai Naemchanthara
Keyword(s):  
Calcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Stoichiometric Composition ◽  
Calcium Nitrate ◽  
Ammonium Phosphate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Calcium Source ◽  
Phosphate Source ◽  
Increasing Temperature

Material that shows hydroxyapatite and β-tricalcium phosphate phases is called biphasic calcium phosphate (BCP). In present work, biphasic calcium phosphate was prepared and characterized for future applications on the utilization of bioactivity of HAp and resorbability of β-TCP properties. It was simply synthesized by precipitation method using eggshell as the calcium source (Ca) in the form of calcium nitrate and ammonium phosphate as the phosphate source (P) to obtain biphasic calcium phosphate. The prepared BCP powders and crystal structure were characterized by X-ray diffraction (XRD), Rietveld refinements and Fourier transform infrared (FT–IR) techniques. The results indicate that BCP was observed at the calcining temperature of 800 oC and above. Furthermore, the crystallinity of BCP increases with increasing temperature from 800 - 1200 oC. The phase fraction of β-TCP is enhanced with pH of a solution from 8.6-10.6 and decrease with the temperature range of 800 - 1200 oC. The formation of BCP arises from its non-stoichiometric composition of materials such as variation of synthesis parameters.

scholarly journals Incorporation of Poly(Vinyl Alcohol) for The Improved Properties of Hydrothermal Derived Calcium Phosphate Cements

2018 ◽  
Vol 18 (2) ◽  
pp. 354
Author(s):  
Nurul Nabilah Razali ◽  
Iis Sopyan
Keyword(s):  
Calcium Phosphate ◽  
Vinyl Alcohol ◽  
Setting Time ◽  
Poly Vinyl Alcohol ◽  
Dihydrogen Phosphate ◽  
Distilled Water ◽  
Ammonium Dihydrogen Phosphate ◽  
Hydrothermal Route ◽  
Ringer’S Solution ◽  
Setting Times

Calcium phosphate cement (CPC) has been synthesized via a straightforward hydrothermal route. Calcium oxide and ammonium dihydrogen phosphate were used as calcium and phosphate precursors. The precursors were refluxed in distilled water at 90–100 °C and dried overnight until the calcium phosphate powder was formed. CPC was then produced by mixing the powder and distilled water at the powder-to-liquid (P/L) ratio of 1.5. Poly(vinyl alcohol) (PVA) of 1 to 7% (w/w) was added and its effect on physical properties was investigated. It was proved that PVA addition up to 7% (w/w) has shortened the setting time but decreased the injectability. The PVA free CPC has the initial and final setting times of 71 and 187 min, respectively and the injectability of 99.92%. The compressive strength also increased with the amount of PVA added in CPC. In addition, soaking CPC in Ringer's solution for 7, 14 and 21 days also gave remarkable effects on cohesion, microstructure and mechanical properties of the cement.

Effect of Capping Agent on Physicochemical Properties of Zinc Substituted Nanoscale Hydroxyapatite

2013 ◽  
Vol 856 ◽  
pp. 304-308
Author(s):  
Seema Kapoor ◽  
Uma Batra ◽  
Suchita Kohli
Keyword(s):  
Calcium Nitrate ◽  
Potassium Dihydrogen Phosphate ◽  
Average Crystallite Size ◽  
Particle Growth ◽  
Zinc Nitrate ◽  
Bet Surface Area ◽  
Dihydrogen Phosphate ◽  
Calcium Nitrate Tetrahydrate ◽  
Capping Agent ◽  
Nitrate Tetrahydrate

Nanoscale zinc substituted hydroxyapatite has been synthesized by solgel technique at 70 C using an aqueous solution of calcium nitrate tetrahydrate (CNT), zinc nitrate tetrahydrate (ZNT) and potassium dihydrogen phosphate (KDP) as starting materials with or without a capping agent, triethanolamine (TEA). The synthesized nanopowders were calcined at two temperatures 800 C and 1000 C for 1 hr. The morphology and size of nanopowders were characterized by transmission electron microscopy. The BET surface area was evaluated from N2 adsorption isotherms. Structural analysis and thermal behavior were investigated by means of Fourier transform infrared spectroscopy, x-ray diffraction and thermogravimetry. The results of TEM confirmed that TEA is effective in reducing average crystallite size from 15 nm in case of zinc substituted hydroxyapatite without TEA (ZnHA) to 9 nm in case of zinc substituted hydroxyapatite with TEA (ZnHA-TEA). FTIR spectra showed the presence of weaker HPO4 bands and stronger O-H bands in case of ZnHA as compared to ZnHA-TEA, which indicated that the formation of the latter is delayed due to TEA assistance. TGA study revealed that ZnHA is thermally more stable as compared to ZnHA-TEA. These results show that the introduction of capping agent effectively restricts the particle growth during precipitation as well as on calcination.

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.

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