Chemical and X-Ray Diffraction Studies of Calcium Phosphates

1938 ◽  
Vol 10 (3) ◽  
pp. 156-161 ◽  
Author(s):  
Harold C. Hodge ◽  
Marian L. LeFevre ◽  
William F. Bale
Keyword(s):  
Calcium Phosphates ◽  
X Ray Diffraction ◽  
X Ray

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Optical and X-Ray Diffraction Studies of Certain Calcium Phosphates

1945 ◽  
Vol 17 (8) ◽  
pp. 491-495 ◽  
Author(s):  
William F. Bale ◽  
John F. Bonner ◽  
Harold C. Hodge ◽  
Howard Adler ◽  
A.R. Wreath ◽  
...  
Keyword(s):  
Calcium Phosphates ◽  
X Ray Diffraction ◽  
X Ray

Characterization of Nano-Biphasic Calcium Phosphates Synthesized under Microwave Curing

2008 ◽  
Vol 3 ◽  
pp. 67-87 ◽  
Author(s):  
Wafa I. Abdel-Fattah ◽  
Fikry M. Reicha ◽  
Tarek A. Elkhooly
Keyword(s):  
Ph Value ◽  
Calcium Phosphates ◽  
Chemical Precipitation ◽  
Calcium Deficiency ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Curing ◽  
Tcp Phase ◽  
Diffraction Patterns

Two biphasic BCP ceramic samples were synthesized by chemical precipitation and microwave curing of calcium deficient hydroxyapatite CDHA under the same pH value and temperature but varied in their initial Ca/P molar ratio. Precipitates were characterization after thermogravimetric analysis, fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption spectroscopy and TEM. Hydroxyapatite (HA) contents were measured for the two biphasic calcium phosphate (BCP) ceramics by sintering the calcium-deficient apatites (CDHA). The results reveal two condensation mechanisms of HPO42- affecting the Ca/P molar ratio after calcination. The X-ray diffraction patterns of BCP powders show the in situ formation of -TCP in the BCP powder. The amount of -TCP phase increases as the initial Ca/P molar ratio decreases due to more calcium deficiency in CDHA structure. The influence of HPO42- incorporation on increasing -TCP phase content after calcination is evaluated. TEM micrographs proved the effect of microwave curing during the preparation process on reducing of particle size to nanoscale range and the destruction of CDHA to finer HA and -TCP particles upon calcination.

scholarly journals Determination of stoichiometric Ca/P ratio in biphasic calcium phosphates using X-ray diffraction analysis

2010 ◽  
Vol 20 (2) ◽  
pp. 93-100 ◽  
Author(s):  
Yong-Keun Song ◽  
Dong-Hyun Kim ◽  
Tae-Wan Kim ◽  
Yang-Do Kim ◽  
Hong-Chae Park ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Calcium Phosphates ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Integrated 3D Information for Custom-Made Bone Grafts: Focus on Biphasic Calcium Phosphate Bone Substitute Biomaterials

2020 ◽  
Vol 17 (14) ◽  
pp. 4931
Author(s):  
Alessandra Giuliani ◽  
Maria Laura Gatto ◽  
Luigi Gobbi ◽  
Francesco Guido Mangano ◽  
Carlo Mangano
Keyword(s):  
Calcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Alveolar Bone ◽  
Sintering Temperature ◽  
Calcium Phosphates ◽  
Compressive Loading ◽  
Peak Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Custom Made

Purpose: Several studies showed that the sintering temperature of 1250 °C could affect the formation of α-Ca3(PO4)2, which is responsible for the reduction of the hardness value of biphasic calcium phosphate biocomposites, but they did not evaluate the inference of the sintering time at peak temperature on transition of β-Ca3(PO4)2 to α-Ca3(PO4)2. This analysis explored, in an innovative way, inferences and correlations between volumetric microstructure, mechanical properties, sintering temperature, and time at peak temperature in order to find the best sintering conditions for biphasic calcium phosphate composites grafted in severe alveolar bone defects. Methods: Sintered biphasic calcium phosphates (30%-hydroxyapatite/70%-tricalcium phosphate) were tested by microCT imaging for the 3D morphometric analysis, by compressive loading to find their mechanical parameters, and by X-ray diffraction to quantify the phases via Rietveld refinement for different sintering temperatures and times at the peak temperature. Data were analysed in terms of statistical inference using Pearson’s correlation coefficients. Results: All the studied scaffolds closely mimicked the alveolar organization of the jawbone, independently on the sintering temperatures and times; however, mechanical testing revealed that the group with peak temperature, which lasted for 2 hours at 1250 °C, showed the highest strength both at the ultimate point and at fracture point. Conclusion: The good mechanical performances of the group with peak temperature, which lasted for 2 hours at 1250 °C, is most likely due to the absence of the α-Ca3(PO4)2 phase, as revealed by X-ray diffraction. However, we detected its presence after sintering at the same peak temperature for longer times, showing the time-dependence, combined with the temperature-dependence, of the β-Ca3(PO4)2 to α-Ca3(PO4)2 transition.

Mapping the density and mineral phase of calcium in bone at the interface with biomaterials using scanning x-ray microscopy

1994 ◽  
Vol 52 ◽  
pp. 44-45
Author(s):  
C. J. Buckley ◽  
S. Downes ◽  
N. Khaleque ◽  
S. J. Bellamy ◽  
X. Zhang
Keyword(s):  
Bone Mineral ◽  
Calcium Phosphates ◽  
X Ray Diffraction ◽  
Mineral Phase ◽  
X Ray ◽  
Prosthetic Implants ◽  
Chemical Phase ◽  
Infra Red ◽  
Rapid Healing ◽  
Prosthetic Implant

Orthopaedic surgery often involves the insertion of a prosthetic implant. For successful and rapid healing, it is important for the prosthesis to make a close and well integrated bond with the bone tissue. To assist this integration, a number of “biomaterials” are on trial as components in the prosthetic implants. Much work is in progress to determine the phase, composition and density of bone mineral at the bone/biomaterial interface. It is expected that the results of this work can be used to develop synthetic calcium phosphates which can be incorporated in prosthetic implants. The composition of bone and biomaterials has been investigated using techniques such as x-ray diffraction, Infra-red, NMR and EXAFS on homogenized samples. However, these studies do not determine the spatial distribution of the bone mineral, its density, localized mineral phase or cellular integration with biomaterials. Electron microscopy with electron probe microanalysis, light and Infra-red microscopy can indicate the presence of mineral in relation to the tissue morphology, but do not give a spatial measure of the density or chemical phase of the mineral at the sub micron level.

Structure of multi-functional calcium phosphates/TiO2 layers deposited on NiTi shape-memory alloy

2017 ◽  
Vol 32 (S1) ◽  
pp. S99-S105
Author(s):  
Tomasz Goryczka ◽  
Karolina Dudek
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Martensitic Transformation ◽  
Calcium Phosphates ◽  
Lattice Parameter ◽  
Original Structure ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Niti Matrix

The structure of the NiTi matrix covered by multi-layer was studied applying X-ray diffraction techniques supported by electron microscopy. Multi-layer was composed from titanium oxide (passivation) followed by mixture of the hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) (electrophoresis). Conditions of deposition as well as sintering did not change the nominal ratio of HAp/TCP and saved their original structure. Also, the passivated NiTi matrix and with HAp/TCP-deposited layer did not change structure. However, sintering, done for HAp/TCP consolidation, introduced local differences in the lattice parameter as well as phase composition of the NiTi matrix. In consequence of that, two-steps martensitic transformation occurred in sintered NiTi/TiO2/Hap–TCP composite.

Amorphous Calcium Phosphates (ACP): Formation and Stability

2005 ◽  
Vol 284-286 ◽  
pp. 7-10 ◽  
Author(s):  
Racquel Z. LeGeros ◽  
Dindo Q. Mijares ◽  
J. Park ◽  
X.-F. Chang ◽  
I. Khairoun ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Synergistic Effects ◽  
Calcium Phosphates ◽  
X Ray Diffraction ◽  
Solution Composition ◽  
X Ray ◽  
Dissolution Properties ◽  
Before And After ◽  
Different Temperatures

Our earlier studies showed that several ions inhibit the crystal growth of apatite and promote the formation of amorphous calcium phosphates (ACP). These ions include: magnesium (Mg), zinc (Zn), stannous (Sn), ferrous (Fe), carbonate (CO3), pyrophosphate (P2O7). The purpose of this study was to investigate the effect of combination of these ions (e.g., Mg & CO3, Mg & P2O7, Mg & Zn, etc) on the formation and stability of ACP. ACP compounds containing the different ions were prepared at 25 and 37oC according to the method we previously described. Chemical stability was investigated by suspending the different ACP preparations in solutions with or without inhibitory ions. Thermal stability was determined by sintering the ACP at different temperatures. Dissolution properties were determined in acidic buffer. The ACP before and after chemical or thermal treatment were analyzed using X-ray diffraction, infrared spectroscopy, and thermogravimetry. Results showed synergistic effects of inhibitory ions on the formation of ACP. ACP materials, regardless of their composition, remained amorphous even after heat treatment at 400oC. Transformation of ACP to other calcium phosphate phases depended on the pH and on the solution composition.

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