scholarly journals Tricalcium phosphate powder: Preparation, characterization and compaction abilities

2017 ◽  
Vol 6 (3) ◽  
pp. 71-76 ◽  
Author(s):  
Abida Fatima ◽  
Elassfouri Mostafa ◽  
Ilou Mohamed ◽  
El ouatli Bahia ◽  
Jamil Mohamed ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
Room Temperature ◽  
Orthophosphoric Acid ◽  
Atomic Ratio ◽  
Wall Friction ◽  
Medical Applications ◽  
Powder Preparation ◽  
Phosphate Powder ◽  
Prepared Powder ◽  
Ionic Impurities

In this work, we characterize tricalcium phosphate powders Ca9(HPO4)(PO4)5(OH) resulting from a reaction between calcium hydroxide and orthophosphoric acid at room temperature, without pH adjustment and in absence of ionic impurities. The prepared powder has an atomic ratio Ca/P of 1.512 ± 0.005. The real density is 2.68 ± 0.02 g/cm3 and the specific surface area is 80 ± 02 m2 /g. During compression, the microstructure of Cadeficient apatite powder with the presence of HPO4 groups seems to support the cohesion between particles. The transmission ratio is 90%, the transfer ratio is 41.8 and the ratio of the die-wall friction is 0.22. These results show that apatitic tricalcium powder gives a good aptitude to the compaction which leads to a good tensile strength (0.79 MPa). The heat treatment of the prepared powder shows the precise temperature for the formation of pyrophosphate, β-TCP and α-TCPa phases. The purity and aptitude to compaction of the prepared powders are very promising for pharmaceutical and medical applications.

The Effect of α-Tricalcium Phosphate Powder Preparation Methods on Cement Properties

2014 ◽  
Vol 614 ◽  
pp. 62-67
Author(s):  
Zilgma Irbe ◽  
Liga Berzina-Cimdina
Keyword(s):  
Particle Size ◽  
Thermal Treatment ◽  
Tricalcium Phosphate ◽  
Solid Phase ◽  
Setting Time ◽  
Deionized Water ◽  
Powder Preparation ◽  
Preparation Methods ◽  
Phosphate Powder ◽  
Powder Particles

The properties of calcium phosphate cements are influenced both by presence of setting aids in cement paste and also by surface properties and particle size distribution of solid phase. In this study the influence of α-tricalcium phosphate powder preparation methods on properties of cement are examined: milling, thermal treatment at temperatures up to 600°C and treatment with deionized water. The properties of cements based on prepared powders evaluated are: setting time, injectability and cohesion. The compressive strength of selected cement samples was determined. Thermal treatment improves injectability, but significantly prolongs setting time and reduces cohesiveness. Treatment of powder particles with deionized water increases setting time, but also significantly reduces injectability. It was not possible to significantly increase powder liquid ratio (from 1.75 to 2.00), if thermally treated powders were used. It was found that reduction of particle size, under certain conditions, can increase the injectability of cements. Powder preparation methods do not significantly affect the compression strength of cement, but fast setting upon the contact water based fluids is necessary to obtain cohesive cements.

scholarly journals Antibiotic delivery potential of nano- and micro-porous marine structure-derived β-tricalcium phosphate spheres for medical applications

Nanomedicine ◽  
2014 ◽  
Vol 9 (8) ◽  
pp. 1131-1139 ◽  
Author(s):  
Joshua Chou ◽  
Stella Valenzuela ◽  
David W Green ◽  
Lawrence Kohan ◽  
Bruce Milthorpe ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
Medical Applications ◽  
Marine Structure ◽  
Antibiotic Delivery

EFFECT OF ION-ENERGY ON THE PROPERTIES OF AMORPHOUS GaN FILMS PRODUCED BY ION-ASSISTED DEPOSITION

2001 ◽  
Vol 15 (28n29) ◽  
pp. 1355-1360 ◽  
Author(s):  
UDAY LANKE ◽  
ANNETTE KOO ◽  
SIMON GRANVILLE ◽  
JOE TRODAHL ◽  
ANDREAS MARKWITZ ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Thermal Evaporation ◽  
Ion Beam ◽  
Atomic Ratio ◽  
Nuclear Reaction Analysis ◽  
Ion Energy ◽  
X Ray ◽  
Nitrogen Ions ◽  
Nitrogen Ion

Amorphous GaN films were deposited on various substrates viz. Si (100), quartz, glass, Al, stainless steel and glassy carbon by thermal evaporation of gallium in the presence of energetic nitrogen ions from a Kaufman source. The films were deposited at room temperature and 5 × 10-4 mbar nitrogen partial pressure. The effect of a low energy nitrogen ion beam during the synthesis of films was investigated for energies 40 eV and 90 eV. The N:Ga atomic ratio, bonding state, microstructure, surface morphology, and electrical properties of the deposited a-GaN films were studied by different characterisation techniques. The films are found to be X-ray amorphous in nature, which is confirmed by Raman spectroscopy. Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA) indicate the N:Ga atomic ratio in the films. The 400-750 eV energy range is thought to be optimal for the production of single-phase amorphous GaN . The effect of ion-energy on optical, Raman, and electrical conductivity measurements of the films is also presented.

Structure and water durability of tin(II) organosilicophosphate glasses prepared by nonaqueous acid–base reactions

2006 ◽  
Vol 21 (7) ◽  
pp. 1798-1806 ◽  
Author(s):  
Megumi Mizuno ◽  
Masahide Takahashi ◽  
Toshinobu Yoko
Keyword(s):  
Room Temperature ◽  
Orthophosphoric Acid ◽  
Chain Structure ◽  
Acid Base ◽  
Humid Atmosphere ◽  
Water Durability ◽  
Magnetic Resonance Technique ◽  
A Chain ◽  
Degree Of Condensation ◽  
High Degree

Tin(II) organosilicophosphate glasses were prepared by nonaqueous acid–base reactions using orthophosphoric acid, dimethyldichlorosilane, and tin(II)chloride as the starting materials. The structure of the methylsiloxane-phosphate copolymer (methylsilicophosphate) and tin(II) methylsilicophosphate glasses was mainly investigated by the 31P nuclear magnetic resonance technique. A chain structure composed of the –(P–O–Si–O)m– silicophosphate bonds was found as the main structural unit in the methylsilicophosphate prepared by mixing orthophosphoric acid and dimethyldichlorosilane at room temperature. Tin(II) methylsilicophosphate glasses could be prepared by introducing SnCl2 as a cross-linking agent of silicophosphate chains. By increasing the reaction temperature, it was possible to promote the reaction and then to increase the network dimensions of the resultant tin(II) methylsilicophosphate glasses. It was found that the glasses with a high degree of condensation tend to have a better water durability in a humid atmosphere.

scholarly journals Microwave-assisted synthesis of calcium phosphate nanowhiskers

2004 ◽  
Vol 19 (6) ◽  
pp. 1876-1881 ◽  
Author(s):  
Sahil Jalota ◽  
A. Cuneyt Tas ◽  
Sarit B. Bhaduri
Keyword(s):  
Calcium Phosphate ◽  
Aqueous Solutions ◽  
Tricalcium Phosphate ◽  
Room Temperature ◽  
Single Phase ◽  
Microwave Oven ◽  
Molten Salt Synthesis ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Auto Ignition

Calcium phosphate [single-phase hydroxyapatite (HA), single-phase tricalcium phosphate (TCP), and biphasic HA-TCP] nanowhiskers and/or powders were produced by using a novel microwave-assisted “combustion synthesis (auto ignition)/molten salt synthesis” hybrid route. This work is an example of our “synergistic processing” philosophy combining these three technologies while taking advantage of their useful aspects. Aqueous solutions containing NaNO3, Ca(NO3)2·4H2O and KH2PO4 (with or without urea) were irradiated in a household microwave oven for 5 min at 600 watts of power. The as-synthesized precursors were then simply stirred in water at room temperature for 1 h to obtain the nanowhiskers or powders of the desired calcium phosphate bioceramics.

The Mechanical Properties and Microstructures of Cement Formed from Pyrophosphoric and Orthophosphoric Acids

2005 ◽  
Vol 284-286 ◽  
pp. 125-128 ◽  
Author(s):  
Liam M. Grover ◽  
Uwe Gbureck ◽  
David Farrar ◽  
J.E. Barralet
Keyword(s):  
Mechanical Properties ◽  
Acid Solution ◽  
Tricalcium Phosphate ◽  
Orthophosphoric Acid ◽  
Marked Change ◽  
Solution Set ◽  
Liquid Ratio ◽  
Setting Times ◽  
Pyrophosphoric Acid ◽  
Orthophosphoric Acid Solution

In this study the setting times, compressive strengths and microstructures of cements formed using pyrophosphoric acid solution and b-tricalcium phosphate (β-TCP; Ca3(PO4)2) were compared with those of cement formed using orthophosphoric acid solution and b-TCP. It was found that cement formed using pyrophosphoric acid solution set more slowly than that formed using orthophosphoric acid and could be mixed to a higher powder to liquid ratio, facilitating the production of cement exhibiting compressive strengths, without pre-compaction, as high as 25 MPa. The use of pyrophosphoric acid as opposed to orthophosphoric acid resulted in a marked change in the microstructure of the cement.

Fabrication of Mg2Si Thermoelectric Materials by Mechanical Alloying and Spark-Plasma Sintering Process

2006 ◽  
Vol 6 (11) ◽  
pp. 3429-3432
Author(s):  
Chung-Hyo Lee ◽  
Seong-Hee Lee ◽  
Sung-Yong Chun ◽  
Sang-Jin Lee
Keyword(s):  
Grain Size ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Atomic Ratio ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

A mixture of pure Mg and Si powders with an atomic ratio 2:1 has been subjected to mechanical alloying (MA) at room temperature to prepare the Mg2Si thermoelectric material. Mg2Si intermetallic compound with a grain size of 50 nm can be obtained by MA of Mg66.7Si33.3 powders for 60 hours and subsequently annealed at 620 °C. Consolidation of the MA powders was performed in a spark plasma sintering (SPS) machine using graphite dies up to 800–900 °C under 50 MPa. The shrinkage of consolidated samples during SPS was significant at about 250 °C and 620 °C. X-ray diffraction data shows that the SPS compact from 60 h MA powders consolidated up to 800 °C consists of only nanocrystalline Mg2Si compound with a grain size of 100 nm.

Thermal and Mechanical Properties of Hf Hydrides with Various Hydrogen Content

2009 ◽  
Vol 1215 ◽  
Author(s):  
Ken Kurosaki ◽  
Masato Ito ◽  
Yuki Kitano ◽  
Hiroaki Muta ◽  
Masayoshi Uno ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Vickers Hardness ◽  
Temperature Effects ◽  
Room Temperature ◽  
Atomic Ratio ◽  
Thermal And Mechanical Properties ◽  
Shear Moduli ◽  
Delta Phase

AbstractFine bulk samples of delta-phase Hf hydride with various hydrogen contents (CH) ranging from 1.62 to 1.72 in the atomic ratio (H/Hf) were prepared, and their thermal and mechanical properties were characterized. In the temperature range from room temperature to around 650 K, the heat capacity and thermal diffusivity of the samples were measured and the thermal conductivity was evacuated. The elastic modulus was calculated from the measured sound velocity. The Vickers hardness was measured at room temperature. Effects of CH and/or temperature on the properties of Hf hydrides were discussed. At room temperature, the thermal conductivity values of the Hf hydrides were 23 Wm−1K−1. The Young's and shear moduli and the Vickers hardness of Hf hydride decreased with increasing CH.

scholarly journals Calcium Phosphate Powder Synthesized from Calcium Acetate and Ammonium Hydrophosphate for Bioceramics Application

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Tatiana Safronova ◽  
Valery Putlayev ◽  
Yaroslav Filippov ◽  
Tatiana Shatalova ◽  
Evgeny Karpushkin ◽  
...  
Keyword(s):  
Phase Composition ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Calcium Acetate ◽  
Molar Ratio ◽  
Composite Ceramics ◽  
Phosphate Powder ◽  
Starting Solution ◽  
By Products ◽  
Ammonium Hydrophosphate

Calcium phosphate powder was synthesized at room temperature from aqueous solutions of ammonium hydrophosphate and calcium acetate without pH adjusting at constant Ca/P molar ratio 1.5. Phase composition of the as-synthesized powder depended on the precursors concentration: At 2.0 M of calcium acetate in the starting solution, poorly crystallized hydroxyapatite was formed, 0.125 M solution of calcium acetate afforded brushite, and the powders synthesized from 0.25–1.0 M calcium acetate solutions were mixtures of the mentioned phases. Firing at 1100 °C led to complete elimination of the reaction by-products, yet the phase composition of the annealed compacted samples was the following: When 2.0 M solution of calcium acetate was used, the obtained ceramics consisted of β-Ca3(PO4)2, whereas at 0.125 to 1.0 M of calcium acetate, the ceramics was a mixture of β-Ca3(PO4)2 and β-Ca2P2O7. Synthesized calcium phosphate powders can be used as the powdered precursors for biocompatible bioresorbable composite ceramics production.

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