Correlation between structure, chromaticity, and dielectric properties of calcium copper pyrophosphates, Ca2−xCuxP2O7 (original) (raw)
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Pure hydroxyapatite and cobalt-containing calcium orthophosphate ceramics were synthesized by the sol-gel method and their properties were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, dielectric impedance spectroscopy and scanning electron microscopy techniques. The average crystallite size of the samples was found to be 30 nm – 56 nm. The crystallinity decreased gradually with the addition of Co. The resistance values were found to be ~10exp12 Ω. Dielectric permittivity and alternating current conductivity of all the samples showed substantial changes in the presence of cobalt. The morphology and particle size distribution of all the samples were changed with increasing amount of Co. In addition, the high content of Co ions was found to both destroy the apatitic structure of the hydroxyapatite and cause the calcium deficiency. The results indicated that, in presence of high amounts of Co, Ca9.5Co(PO4)7 ceramics could be prepared.
Synthesis and thermal characterization of copper and calcium mixed phosphates
Journal of Thermal Analysis and Calorimetry, 2007
A series of compounds with composition of Ca 1-x Cu x HPO 4 , where x varied from 0.05 to 0.5 were synthesized by precipitation method. The compounds were characterized by elemental analysis, X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and thermogravimetry. The chemical stabilities of solids were investigated at several pH. Elemental analysis of copper, calcium and phosphorus are in agreement with the proposed composition. The formation of lamellar phosphates was evidenced. The stability of the set of compounds was better for samples with high copper content.
Synthesis and thermal behavior of double copper and potassium pyrophosphate
Thermochimica Acta, 2009
Complex mineral fertilizer PK fertilizer Double copper and potassium pyrophosphate Thermal behavior X-ray diffractometry Energy dispersive X-ray spectroscopy Scanning electron microscopy a b s t r a c t This paper presents the synthesis and thermal behavior of double copper and potassium pyrophosphate, which can be used as a PK fertilizer containing copper as micronutrient. In order to find the conditions for the synthesis of this compound from copper sulphate and potassium pyrophosphate, various Cu 2+ :P 2 O 7 4− molar ratios (0:1-2:1), various molar concentrations of the solutions (0.075; 0.1; 0.15 and 0.2 mol L −1 ) and various temperatures (25, 50, 75 and 100 • C) have been used. The solid product synthesized in optimum conditions for the separation of micronutrient copper from the reaction mass (Cu 2+ :P 2 O 7 4− molar ratio 1:1, concentration 0.1 mol L −1 ) was subjected to a complex study: chemical analysis, thermal analysis, energy dispersive X-ray spectroscopy, scanning electron microscopy and X-ray diffractometry. During heating up to 1000 • C, K 2 Cu 3 (P 2 O 7 ) 2 ·3H 2 O loses the crystallization water; several transformations of the phosphates also take place: the decomposition of pyrophosphates to ortho-phosphates; the transformation of ortho-phosphates; the polymerization of a fraction of ortho-phosphates to amorphous phosphates with longer chains; the reorganization of ortho-phosphates and poly-phosphates to pyrophosphates and their crystallization. The decomposition mechanism was confirmed when using the X-ray diffraction patterns of the compound, thermally treated at several temperatures.
European Journal of Chemistry
The title compounds are members of the M2O-CuO-P2O5 system (M = Li, Na, K and Rb), where the lithium, sodium, potassium, rubidium and cesium phases have already been structurally characterized. The studied diphosphates LiNaCuP2O7, LiKCuP2O7 and Rb0.5Na1.5CuP2O7 belong to a large family of materials of general formula, MM’CuP2O7 (M, M’ = Monovalent cation) where the elements M and M’ ionic radii are decisive in the structural type determination. They were synthesized by solid-state reactions. The X-ray structural analysis show that these compounds crystallize in the P21/n monoclinic lattice where the CuO5 pyramidal square are linked to nearly eclipsed P2O7 groups by corner sharing to build up corrugated layers [CuP2O7]2- extending perpendicularly to [010]. The Li+, Na+, K+ and Rb+ cations reside in the interlayer space and in cavities delimited by the anionic network. In this study, the synthesis, the structure, the powder diffraction, the infrared spectroscopy, the thermal analysis ...
Crystals, 2019
C a 2.90 M e 0.10 2 + ( P O 4 ) 2 (with Me = Mn, Ni, Cu) β-tricalcium phosphate (TCP) powders were synthesized by solid-state reaction at T = 1200 °C and investigated by means of a combination of scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, and luminescence spectroscopy. SEM morphological analysis showed the run products to consist of sub spherical microcrystalline aggregates, while EDS semi-quantitative analysis confirmed the nominal Ca/Me composition. The unit cell and the space group were determined by X-ray powder diffraction data showing that all the compounds crystallize in the rhombohedral R3c whitlockite-type structure, with the following unit cell constants: a = b = 10.41014(19) Å, c = 37.2984(13) Å, and cell volume V = 3500.53(15) Å3 (Mn); a = b = 10.39447(10) Å, c = 37.2901(8) Å; V = 3489.22(9) Å3 (Ni); a = b = 10.40764(8) Å, c = 37.3158(6) Å, V...
Powder XRD and dielectric studies of gel grown calcium pyrophosphate crystals
2013
Formation of calcium pyrophosphate dihydrate (CPPD) crystals in soft tissues such as cartilage, meniscus and synovial tissue leads to CPPD deposition diseases. The appearance of these crystals in the synovial fluid can give rise to an acute arthritic attack with pain and inflammation of the joints, a condition called pseudo-gout. The growth of CPP crystals has been carried out, in the present study, using the single diffusion gel growth technique, which can broadly mimic in vitro the condition in soft tissues. The crystals were characterized by different techniques. The FTIR study revealed the presence of various functional groups. Powder XRD study was also carried out to verify the crystal structure. The dielectric study was carried out at room temperature by applying field of different frequency from 500 Hz to 1 MHz. The dielectric constant, dielectric loss and a.c. resistivity decreased as frequency increased, whereas the a.c. conductivity increased as frequency increased.
New copper phosphates with the NASICON or alluaudite-type structures as ionic or mixed conductors☆
Solid State Ionics
The electrical properties of the copper(I) phosphates CuTi2(PO4)3, CuTiZr(PO4)3, CuZr2(PO4)3, Cu2ZrSc(PO4)3 and Cu2TiCr (PO4)3 which adopt the NASICON structure are reviewed with comparison to their sodium analogues. Two new compounds (CuXCu n) L3S (FenFe m) 3 (PO4) 3 and CuICullMg3 (PO 4) 3 exhibiting the alluaudite-type structure have been prepared and characterised. CuXCullMg3 (PO4) 3 shows mixed copper valency and mixed conductivity, with a roughly temperature independent transport number tion(Cu2Mg3(PO4)3)-0.3, and E.=0.96 eV, suggesting a coupling of the two transport mechanisms. A mechanistic comparison is made with the mixed valence NASICON compound Na2.sZrFeno.sFemo. 5 (PO4)3.
Dielectric Properties of Calcium Phosphate Ceramics
Materials Science, 2016
Calcium phosphate ceramics with various Ca/P ratios of 1, 2, 3, 4 and 8 were synthesized via sol-gel route. The effects of Ca/P molar ratio on structural, morphological and dielectric properties were investigated in detail using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and dielectric measurements. The Ca/P molar ratio significantly affects the crystal structure and phase composition. The crystallite size, lattice parameters and volume of the unit cell were remarkably affected by the change in the Ca/P molar ratio. The microstructure is changed with increasing the Ca/P molar ratio. The relative permittivity and alternating current conductivity gradually decrease for the samples having the Ca/P ratios higher than 2. The dielectric loss decreases gradually with the increase of the molar ratio of Ca/P.
Synthesis of triclinic calcium pyrophosphate crystals
Journal of Materials Science: Materials in Medicine, 2007
This paper presents a method for preparing crystals of triclinic calcium pyrophosphate (t-CPPD). A calcium pyrophosphate intermediate is first prepared by reaction of potassium pyrophosphate and calcium chloride. Samples of the intermediate are dissolved in hydrochloric acid and urea added. Upon heating to 95-100°C, hydrolysis of the urea causes the pH to rise and t-CPPD crystallises out. Purity of the product was ascertained by chemical and physical analysis. Where large crystals are required an unstirred system is used, while smaller crystals are produced by stirring the reaction mixture.