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Abbas Fahami - One of the best experts on this subject based on the ideXlab platform.
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mechanosynthesis of carbonate doped Chlorapatite zno nanocomposite with negative zeta potential
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. BeallAbstract:Abstract Carbonate doped Chlorapatite–ZnO composite nanopowders with negative zeta potential were synthesized by one step mechanochemical process as a novel bioceramic. Results indicated that the formation of carbonate doped Chlorapatite–ZnO composite was varied by incorporation of different ZnO contents. In the presence of 3, 6, 9, 12, and 15 wt% ZnO, carbonate doped Chlorapatite–ZnO composite nanopowders were produced successfully after 1 h of milling. There was no trace of carbonate doped Chlorapatite based composite as ZnO content increased to 20 wt%. According to the X-ray diffraction data, the average crystallite size, and the degree of crystallinity of the product decreased slightly as ZnO contents increased from 0 to 15 wt%. Conversely, lattice strain increased gradually. Subsequent annealing at 800 °C for 1 h of carbonate doped Chlorapatite–12 wt% ZnO composite indicated larger crystallite size and the degree of crystallinity. The zeta potential of nanoparticles (12 wt% ZnO sample) suspended in physiological saline (0.154 M NaCl) was determined. The zeta potential was almost zero for pH=3 and negative values for pH=5–11 and –22.52 ±1.96 mV at pH 7.4. Negative zeta potential is reported to favor apatite nucleation, bone regeneration, as well as osseointegration. Microscopic observations illustrated that the final product had a cluster-like structure containing ZnO platelets as well as polygonal and spherical particles with an average particle size of approximately ranged from 20±10 to 50±10 nm. To our knowledge, this is the first report of the synthesis of carbonate doped Chlorapatite–ZnO composite nanopowders; the nanocomposite reported here can be a promising candidate for use in biomedical applications.
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Mechanosynthesis of carbonate doped Chlorapatite–ZnO nanocomposite with negative zeta potential
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. BeallAbstract:Abstract Carbonate doped Chlorapatite–ZnO composite nanopowders with negative zeta potential were synthesized by one step mechanochemical process as a novel bioceramic. Results indicated that the formation of carbonate doped Chlorapatite–ZnO composite was varied by incorporation of different ZnO contents. In the presence of 3, 6, 9, 12, and 15 wt% ZnO, carbonate doped Chlorapatite–ZnO composite nanopowders were produced successfully after 1 h of milling. There was no trace of carbonate doped Chlorapatite based composite as ZnO content increased to 20 wt%. According to the X-ray diffraction data, the average crystallite size, and the degree of crystallinity of the product decreased slightly as ZnO contents increased from 0 to 15 wt%. Conversely, lattice strain increased gradually. Subsequent annealing at 800 °C for 1 h of carbonate doped Chlorapatite–12 wt% ZnO composite indicated larger crystallite size and the degree of crystallinity. The zeta potential of nanoparticles (12 wt% ZnO sample) suspended in physiological saline (0.154 M NaCl) was determined. The zeta potential was almost zero for pH=3 and negative values for pH=5–11 and –22.52 ±1.96 mV at pH 7.4. Negative zeta potential is reported to favor apatite nucleation, bone regeneration, as well as osseointegration. Microscopic observations illustrated that the final product had a cluster-like structure containing ZnO platelets as well as polygonal and spherical particles with an average particle size of approximately ranged from 20±10 to 50±10 nm. To our knowledge, this is the first report of the synthesis of carbonate doped Chlorapatite–ZnO composite nanopowders; the nanocomposite reported here can be a promising candidate for use in biomedical applications.
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Effect of high-energy ball milling on the formation and microstructural features of carbonated Chlorapatite nanopowders
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. Beall, Bahman Nasiri-tabrizi, Belinda Pingguan-murphyAbstract:Carbonated Chlorapatite nanopowders (n-CCAp) were synthesized by mechanochemical process from calcite (CaCO3), phosphorus pentoxide (P2O5), and calcium chloride (CaCl2) as raw materials. Results demonstrated that the formation of n-CCAp was influenced strongly by the milling time. At the beginning of milling (up to 15 min), CaCO3 and CaCl2 were the dominant phases, while P2O5 disappeared entirely due to its very high deliquescent nature. With increasing the milling time to 600 min, the progressive mechanochemical reaction was completed which resulted in the formation of nanostructured carbonated Chlorapatite. According to the X-ray diffraction data, crystallite size of the product decreased from 24 +/- 1 to 21 +/- 2 nm when the milling time increased from 180 to 600 mm, respectively. Microscopic observations illustrated that the final product had a cluster-like structure which was composed of polygonal particles with an average particle size of approximately 15 +/- 10 nm. To our knowledge, this is the first report of the production of pure n-CCAp; the synthesis reported here can be a promising candidate for use in biomedical applications. Structure and morphology evolution of product are reported here and have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FUR), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
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effects of composition and milling medium on mechanosynthesis of Chlorapatite alumina composite nanopowders
Ceramics International, 2014Co-Authors: Abbas Fahami, Bahman Nasiritabrizi, Reza EbrahimikahrizsangiAbstract:Abstract The effects of alumina content and milling medium on the formation of Chlorapatite-based composite nanopowders were studied. The powder mixtures with various compositions were activated in a high-energy planetary ball mill for 5 h using two distinct milling media. The first medium (M 1 ) was composed of sealed tempered chrome steel vial and un-fused alumina balls. The second medium (M 2 ) consisted of sealed tempered chrome steel vial and balls. In the presence of different amounts of γ-Al 2 O 3 , no mechanochemical reaction occurred in M 1 medium. In contrast, in the second medium (M 2 ), Chlorapatite−alumina composite nanopowders were obtained after 5 h of milling in the presence of 4 and 7 wt% alumina. In the presence of 4 wt% alumina, crystallite size and lattice strain of the product were about 30±2 nm and 0.62±0.031%, respectively. With increasing the alumina content to 7 wt%, the lattice strain declined to 0.57±0.029%, while the crystalline size increased to around 32±2 nm. From the electron microscopic images, the synthesized composite nanopowder had a cluster-like structure with an average particle size of about 97 nm.
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influence of titania content on mechanosynthesis of Chlorapatite titania composite nanopowders
Ceramics International, 2014Co-Authors: Abbas Fahami, Bahman NasiritabriziAbstract:Abstract The effect of titania content on mechanochemical synthesis of Chlorapatite–titania composite nanopowders was studied for the first time. According to the obtained data, the phase compositions, structural features as well as morphological characteristics of the composites were influenced by the titania content. In the presence of 3–5 wt% titania, milling for 5 h resulted in the formation of Chlorapatite–titania composite nanopowders. The crystallite size of the samples was around 25±1 and 23±1 nm in the presence of 3 and 5 wt% titania, respectively. With increasing the titania content to 7 wt%, no chemical reaction happened during the milling. The composite nanopowders showed high volume fraction of grain boundaries. Based on the FT-IR results, the products had high chemical purity which is very important in biomedical applications. The TEM images indicated that the composite nanopowder was composed of spheroidal particles with a mean size of around 35 nm. The proposed synthesis strategy provides a facile pathway to obtain novel Chlorapatite-based composite nanopowders with high purity and optimal properties.
Bahman Nasiri-tabrizi - One of the best experts on this subject based on the ideXlab platform.
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Effect of high-energy ball milling on the formation and microstructural features of carbonated Chlorapatite nanopowders
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. Beall, Bahman Nasiri-tabrizi, Belinda Pingguan-murphyAbstract:Carbonated Chlorapatite nanopowders (n-CCAp) were synthesized by mechanochemical process from calcite (CaCO3), phosphorus pentoxide (P2O5), and calcium chloride (CaCl2) as raw materials. Results demonstrated that the formation of n-CCAp was influenced strongly by the milling time. At the beginning of milling (up to 15 min), CaCO3 and CaCl2 were the dominant phases, while P2O5 disappeared entirely due to its very high deliquescent nature. With increasing the milling time to 600 min, the progressive mechanochemical reaction was completed which resulted in the formation of nanostructured carbonated Chlorapatite. According to the X-ray diffraction data, crystallite size of the product decreased from 24 +/- 1 to 21 +/- 2 nm when the milling time increased from 180 to 600 mm, respectively. Microscopic observations illustrated that the final product had a cluster-like structure which was composed of polygonal particles with an average particle size of approximately 15 +/- 10 nm. To our knowledge, this is the first report of the production of pure n-CCAp; the synthesis reported here can be a promising candidate for use in biomedical applications. Structure and morphology evolution of product are reported here and have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FUR), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
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Structural and morphological study of mechanochemically synthesized crystalline nanoneedles of Zr-doped carbonated Chlorapatite
Materials Letters, 2015Co-Authors: Bahman Nasiri-tabrizi, Erfan Zalnezhad, Belinda Pingguan-murphy, Wan Jefrey Basirun, Abdel Magid Hamouda, S. BaradaranAbstract:Abstract Nanosize Zr-doped carbonated Chlorapatite (n-ZCCA) was developed as a novel bioceramic by a ball milling process. Results showed that the microstructural characteristics of the product were affected significantly by the degree of substitution and subsequent annealing at 800 °C for 1 h. In the absence of zirconium, mechanical activation for 3 h resulted in the formation of carbonated hydroxyapatite (CHA). With the addition of various amounts of zirconium, nanosize Zr-doped carbonated chlorhydroxyapatite (n-ZCCHA) and n-ZCCA were formed as a result of progressive mechanochemical reactions. From the HR-TEM images, the preferential substitution of Zr onto the ac or bc Chlorapatite crystal facets (rich in calcium ions) led to a c -axis oriented crystal growth of crystalline nanoneedles with an average size of around 40–60 nm in length and 10–20 nm in width.
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Influence of titania content on mechanosynthesis of Chlorapatite–titania composite nanopowders
Ceramics International, 2014Co-Authors: Abbas Fahami, Bahman Nasiri-tabriziAbstract:Abstract The effect of titania content on mechanochemical synthesis of Chlorapatite–titania composite nanopowders was studied for the first time. According to the obtained data, the phase compositions, structural features as well as morphological characteristics of the composites were influenced by the titania content. In the presence of 3–5 wt% titania, milling for 5 h resulted in the formation of Chlorapatite–titania composite nanopowders. The crystallite size of the samples was around 25±1 and 23±1 nm in the presence of 3 and 5 wt% titania, respectively. With increasing the titania content to 7 wt%, no chemical reaction happened during the milling. The composite nanopowders showed high volume fraction of grain boundaries. Based on the FT-IR results, the products had high chemical purity which is very important in biomedical applications. The TEM images indicated that the composite nanopowder was composed of spheroidal particles with a mean size of around 35 nm. The proposed synthesis strategy provides a facile pathway to obtain novel Chlorapatite-based composite nanopowders with high purity and optimal properties.
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Phase transitions and structural changes of nanostructured Chlorapatite under thermal treatment
Ceramics International, 2014Co-Authors: Bahman Nasiri-tabrizi, Abbas Fahami, Reza Ebrahimi-kahrizsangiAbstract:Abstract The influence of thermal treatment on phase transformations and structural features of mechanosynthesized Chlorapatite nanopowders was investigated. Results showed that the phase composition of the product was influenced by the ball to powder weight ratio. During annealing in the range of 900–1300 °C for 1 h, decomposition of Chlorapatite to tricalcium phosphate, tetracalcium phosphate, and hydrochloric acid occurred. The rate of decomposition increased gradually with increasing the annealing temperature to 1300 °C. According to the obtained data, during milling process the lattice strain increased significantly to about 1.08%, while the crystalline size declined sharply to around 28.89 nm. After thermal treatment, the crystallite size of Chlorapatite went up notably due to a dramatic decrease in residual elastic strain. The crystallinity degree of the 5 h milled sample was about 78.14%. This value reached around 92.86% after annealing at 1300 °C. Scanning electron microscope images indicated that the milled sample had cluster-like structure which was consisted of fine particles with a mean size of about 95 nm. During heating in the range of 900–1100 °C, the coalescence of nanoparticles with spheroidal and polygonal morphologies occurred. After annealing at 1300 °C the microstructure showed a coarse structure characterized by the presence of grains with an average size of around 3 μm.
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Synthesis and characterization of Chlorapatite–ZnO composite nanopowders
Ceramics International, 2014Co-Authors: Bahman Nasiri-tabrizi, Abbas FahamiAbstract:Abstract The influence of zinc oxide content on the formation of Chlorapatite-based composite nanopowders in the mechanically alloyed CaO–CaCl 2 –P 2 O 5 –ZnO system was studied. To mechanosynthesize composite nanopowders, different amounts of hydrothermally synthesized zinc oxide nanoparticles (0–10 wt%) were mixed with ingredients and then were mechanically activated for 5 h. Results showed that in the absence of zinc oxide, high crystalline Chlorapatite nanopowder was obtained after 5 h of milling. In the presence of 4 and 7 wt% zinc oxide, the main product of milling for 5 h was Chlorapatite–zinc oxide composite nanopowder. On increasing the zinc oxide content to 10 wt%, composite nanopowder was not formed due to improper stoichiometric ratio of the reactants. The crystallite size, lattice strain, volume fraction of grain boundary, and crystallinity degree of the samples fluctuated significantly during the milling process. In the presence of 7 wt% zinc oxide, the crystallite size and crystallinity degree reached 51±2 nm and 79±2%, respectively. During annealing at 900 °C for 1 h, the crystallization of composite nanopowder occurred and as a result the crystallinity degree rose sharply to 96±3%. In addition, the crystallite size increased to 77±2 nm after annealing at 900 °C. According to SEM and TEM images, the composite nanopowder was composed of both ellipse-like and polygonal particles with a mean size of about 98 nm.
Bahman Nasiritabrizi - One of the best experts on this subject based on the ideXlab platform.
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effects of composition and milling medium on mechanosynthesis of Chlorapatite alumina composite nanopowders
Ceramics International, 2014Co-Authors: Abbas Fahami, Bahman Nasiritabrizi, Reza EbrahimikahrizsangiAbstract:Abstract The effects of alumina content and milling medium on the formation of Chlorapatite-based composite nanopowders were studied. The powder mixtures with various compositions were activated in a high-energy planetary ball mill for 5 h using two distinct milling media. The first medium (M 1 ) was composed of sealed tempered chrome steel vial and un-fused alumina balls. The second medium (M 2 ) consisted of sealed tempered chrome steel vial and balls. In the presence of different amounts of γ-Al 2 O 3 , no mechanochemical reaction occurred in M 1 medium. In contrast, in the second medium (M 2 ), Chlorapatite−alumina composite nanopowders were obtained after 5 h of milling in the presence of 4 and 7 wt% alumina. In the presence of 4 wt% alumina, crystallite size and lattice strain of the product were about 30±2 nm and 0.62±0.031%, respectively. With increasing the alumina content to 7 wt%, the lattice strain declined to 0.57±0.029%, while the crystalline size increased to around 32±2 nm. From the electron microscopic images, the synthesized composite nanopowder had a cluster-like structure with an average particle size of about 97 nm.
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influence of titania content on mechanosynthesis of Chlorapatite titania composite nanopowders
Ceramics International, 2014Co-Authors: Abbas Fahami, Bahman NasiritabriziAbstract:Abstract The effect of titania content on mechanochemical synthesis of Chlorapatite–titania composite nanopowders was studied for the first time. According to the obtained data, the phase compositions, structural features as well as morphological characteristics of the composites were influenced by the titania content. In the presence of 3–5 wt% titania, milling for 5 h resulted in the formation of Chlorapatite–titania composite nanopowders. The crystallite size of the samples was around 25±1 and 23±1 nm in the presence of 3 and 5 wt% titania, respectively. With increasing the titania content to 7 wt%, no chemical reaction happened during the milling. The composite nanopowders showed high volume fraction of grain boundaries. Based on the FT-IR results, the products had high chemical purity which is very important in biomedical applications. The TEM images indicated that the composite nanopowder was composed of spheroidal particles with a mean size of around 35 nm. The proposed synthesis strategy provides a facile pathway to obtain novel Chlorapatite-based composite nanopowders with high purity and optimal properties.
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synthesis and characterization of Chlorapatite zno composite nanopowders
Ceramics International, 2014Co-Authors: Bahman Nasiritabrizi, Abbas FahamiAbstract:Abstract The influence of zinc oxide content on the formation of Chlorapatite-based composite nanopowders in the mechanically alloyed CaO–CaCl 2 –P 2 O 5 –ZnO system was studied. To mechanosynthesize composite nanopowders, different amounts of hydrothermally synthesized zinc oxide nanoparticles (0–10 wt%) were mixed with ingredients and then were mechanically activated for 5 h. Results showed that in the absence of zinc oxide, high crystalline Chlorapatite nanopowder was obtained after 5 h of milling. In the presence of 4 and 7 wt% zinc oxide, the main product of milling for 5 h was Chlorapatite–zinc oxide composite nanopowder. On increasing the zinc oxide content to 10 wt%, composite nanopowder was not formed due to improper stoichiometric ratio of the reactants. The crystallite size, lattice strain, volume fraction of grain boundary, and crystallinity degree of the samples fluctuated significantly during the milling process. In the presence of 7 wt% zinc oxide, the crystallite size and crystallinity degree reached 51±2 nm and 79±2%, respectively. During annealing at 900 °C for 1 h, the crystallization of composite nanopowder occurred and as a result the crystallinity degree rose sharply to 96±3%. In addition, the crystallite size increased to 77±2 nm after annealing at 900 °C. According to SEM and TEM images, the composite nanopowder was composed of both ellipse-like and polygonal particles with a mean size of about 98 nm.
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thermally induced crystallization of Chlorapatite zno nanocomposite
Materials Letters, 2014Co-Authors: Abbas Fahami, Bahman NasiritabriziAbstract:Abstract The thermally induced crystallization of the mechanosynthesized Chlorapatite–ZnO composite nanopowder was investigated. In the presence of 7 wt% ZnO, the milling for 5 h resulted in the formation of a composite nanopowder with the crystallite size of 51±2 nm. During thermal treatment, the crystallization of the composite nanopowder occurred and the crystallinity degree reached a maximum of 96±3% at 900 °C. After annealing at 1300 °C, β-TCP and Ca 4 P 2 O 9 were formed due to the severe decomposition of the composite. According to SEM images, the mechanosynthesized powder showed a cluster-like structure composed of fine particles with an average size of about 98 nm. During heating at 900 °C, the coalescence of nanoparticles occurred and eventually a coarse microstructure with a mean particle size of around 3 μm was formed after annealing at 1300 °C.
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mechanosynthesis and characterization of Chlorapatite nanopowders
Materials Letters, 2013Co-Authors: Abbas Fahami, Bahman Nasiritabrizi, Reza EbrahimikahrizsangiAbstract:Abstract Chlorapatite nanopowders (n-CAp) were produced by a novel facile mechanochemical process. Results showed that the formation of n-CAp proceeded in several steps. At the beginning of milling, the main products were stoichiometrically deficient Chlorapatite and calcium oxide. Eventually, high crystalline CAp nanopowder was obtained after 300 min of milling. By increasing the milling time to 300 min, the lattice strain increased significantly to around 0.0108±0.0005, while the crystalline size declined sharply to about 28±2 nm. Similarly, the crystallinity degree of the samples was influenced by the milling time and reached about 77±4% after 300 min of milling. SEM observations indicated that the milled sample had cluster-like structure which was consisted of fine particles with a mean size of about 95 nm.
Gary W. Beall - One of the best experts on this subject based on the ideXlab platform.
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mechanosynthesis of carbonate doped Chlorapatite zno nanocomposite with negative zeta potential
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. BeallAbstract:Abstract Carbonate doped Chlorapatite–ZnO composite nanopowders with negative zeta potential were synthesized by one step mechanochemical process as a novel bioceramic. Results indicated that the formation of carbonate doped Chlorapatite–ZnO composite was varied by incorporation of different ZnO contents. In the presence of 3, 6, 9, 12, and 15 wt% ZnO, carbonate doped Chlorapatite–ZnO composite nanopowders were produced successfully after 1 h of milling. There was no trace of carbonate doped Chlorapatite based composite as ZnO content increased to 20 wt%. According to the X-ray diffraction data, the average crystallite size, and the degree of crystallinity of the product decreased slightly as ZnO contents increased from 0 to 15 wt%. Conversely, lattice strain increased gradually. Subsequent annealing at 800 °C for 1 h of carbonate doped Chlorapatite–12 wt% ZnO composite indicated larger crystallite size and the degree of crystallinity. The zeta potential of nanoparticles (12 wt% ZnO sample) suspended in physiological saline (0.154 M NaCl) was determined. The zeta potential was almost zero for pH=3 and negative values for pH=5–11 and –22.52 ±1.96 mV at pH 7.4. Negative zeta potential is reported to favor apatite nucleation, bone regeneration, as well as osseointegration. Microscopic observations illustrated that the final product had a cluster-like structure containing ZnO platelets as well as polygonal and spherical particles with an average particle size of approximately ranged from 20±10 to 50±10 nm. To our knowledge, this is the first report of the synthesis of carbonate doped Chlorapatite–ZnO composite nanopowders; the nanocomposite reported here can be a promising candidate for use in biomedical applications.
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Mechanosynthesis of carbonate doped Chlorapatite–ZnO nanocomposite with negative zeta potential
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. BeallAbstract:Abstract Carbonate doped Chlorapatite–ZnO composite nanopowders with negative zeta potential were synthesized by one step mechanochemical process as a novel bioceramic. Results indicated that the formation of carbonate doped Chlorapatite–ZnO composite was varied by incorporation of different ZnO contents. In the presence of 3, 6, 9, 12, and 15 wt% ZnO, carbonate doped Chlorapatite–ZnO composite nanopowders were produced successfully after 1 h of milling. There was no trace of carbonate doped Chlorapatite based composite as ZnO content increased to 20 wt%. According to the X-ray diffraction data, the average crystallite size, and the degree of crystallinity of the product decreased slightly as ZnO contents increased from 0 to 15 wt%. Conversely, lattice strain increased gradually. Subsequent annealing at 800 °C for 1 h of carbonate doped Chlorapatite–12 wt% ZnO composite indicated larger crystallite size and the degree of crystallinity. The zeta potential of nanoparticles (12 wt% ZnO sample) suspended in physiological saline (0.154 M NaCl) was determined. The zeta potential was almost zero for pH=3 and negative values for pH=5–11 and –22.52 ±1.96 mV at pH 7.4. Negative zeta potential is reported to favor apatite nucleation, bone regeneration, as well as osseointegration. Microscopic observations illustrated that the final product had a cluster-like structure containing ZnO platelets as well as polygonal and spherical particles with an average particle size of approximately ranged from 20±10 to 50±10 nm. To our knowledge, this is the first report of the synthesis of carbonate doped Chlorapatite–ZnO composite nanopowders; the nanocomposite reported here can be a promising candidate for use in biomedical applications.
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Effect of high-energy ball milling on the formation and microstructural features of carbonated Chlorapatite nanopowders
Ceramics International, 2015Co-Authors: Abbas Fahami, Gary W. Beall, Bahman Nasiri-tabrizi, Belinda Pingguan-murphyAbstract:Carbonated Chlorapatite nanopowders (n-CCAp) were synthesized by mechanochemical process from calcite (CaCO3), phosphorus pentoxide (P2O5), and calcium chloride (CaCl2) as raw materials. Results demonstrated that the formation of n-CCAp was influenced strongly by the milling time. At the beginning of milling (up to 15 min), CaCO3 and CaCl2 were the dominant phases, while P2O5 disappeared entirely due to its very high deliquescent nature. With increasing the milling time to 600 min, the progressive mechanochemical reaction was completed which resulted in the formation of nanostructured carbonated Chlorapatite. According to the X-ray diffraction data, crystallite size of the product decreased from 24 +/- 1 to 21 +/- 2 nm when the milling time increased from 180 to 600 mm, respectively. Microscopic observations illustrated that the final product had a cluster-like structure which was composed of polygonal particles with an average particle size of approximately 15 +/- 10 nm. To our knowledge, this is the first report of the production of pure n-CCAp; the synthesis reported here can be a promising candidate for use in biomedical applications. Structure and morphology evolution of product are reported here and have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FUR), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Shuji Oishi - One of the best experts on this subject based on the ideXlab platform.
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Highly Crystalline Chlorapatite Films Prepared by the Evaporation of a Sodium Chloride Flux
Crystal Growth & Design, 2008Co-Authors: Katsuya Teshima, Mitsuo Sakurai, Kunio Yubuta, Yutaka Sonobayashi, Takaomi Suzuki, Toetsu Shishido, Hiroyuki Sugimura, Shuji OishiAbstract:Environmentally friendly, high-quality, and transparent-colorless calcium Chlorapatite (Ca5Cl(PO4)3) films were easily fabricated for the first time by the flux evaporation of the NaCl flux. The intermediate layer was essential to form the Chlorapatite film on the sapphire surface. The film is thought to epitaxially grow on the (0001) sapphire surface because very smooth and well-developed {1010} faces were observed.
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surface free energy and morphology of Chlorapatite crystals grown from sodium chloride flux
Bulletin of the Chemical Society of Japan, 2006Co-Authors: Takaomi Suzuki, Mitsunobu Shimuta, Shuji OishiAbstract:Well-formed crystals of barium Chlorapatite [Ba 5 Cl(PO 4 ) 3 ] and strontium Chlorapatite [Sr 5 Cl(PO 4 ) 3 ] were grown from a sodium chloride flux. The contact angle of water on the (1010) face of each Chlorapatite crystal was observed using a modified Wilhelmy method, where we measured the change of liquid weight instead of the crystal weight. The contact angle depends on the aspect ratio of the crystal. Both the advancing and receding contact angles were larger for Ba 5 Cl(PO 4 ) 3 and Sr 5 Cl(PO 4 ) 3 crystals with larger aspect ratios. The surface free energy of the (1010) face was calculated using Neumann's equation. The (1010) face of the crystals of larger aspect ratios has a smaller surface free energy, indicating that such crystals have a more stable (1010) face than the crystals of smaller aspect ratios. This result corresponds to the morphology of the Chlorapatite crystals because the crystals have a tendency to elongate into the [0001] direction.
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Effect of Metal Ions of Chlorapatites on the Topotaxial Replacement by Hydroxyapatite under Hydrothermal Conditions
Journal of Solid State Chemistry, 2000Co-Authors: J.c. Rendón-angeles, Kazumichi Yanagisawa, Nobuo Ishizawa, Shuji OishiAbstract:Abstract The effect of the metal ions in the Chlorapatite structure on the topotaxial conversion to the hydroxyapatite structure was investigated, using three different types of Chlorapatite single crystals, calcium, strontium, and barium Chlorapatite. The topotaxial conversion to the hydroxyapatite structure was conducted under hydrothermal conditions at a range of temperature from 300 to 800°C for intervals between 3 and 96 h in concentrated KOH solutions. The Cl− ion exchange in the calcium and strontium Chlorapatite crystals was completed at 500 and 700°C in a 6.25 M KOH solution, respectively, which resulted in the formation of hydroxyapatite structure. The transformed crystals retained their original shape and dimensions due to the topotaxial transformation. In contrast, the rate of the topotaxial conversion was further reduced on the barium Chlorapatite crystals that contain metal ions with large size such as Ba. These crystals were only partially converted to hydroxyapatite even at 800°C in 10 M KOH solution. Under these conditions, a dissolution of ion species of the topotaxially converted barium hydroxyapatite layer was observed, which resulted in the precipitation of new crystals on the surface of the remaining barium Chlorapatite crystals. The structure of the new crystals was matched with the hexagonal apatite structure, but a great amount of K was incorporated in the structure.
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Topotaxial Conversion of Chlorapatite and Hydroxyapatite to Fluorapatite by Hydrothermal Ion Exchange
Chemistry of Materials, 2000Co-Authors: J.c. Rendón-angeles, Kazumichi Yanagisawa, Nobuo Ishizawa, Shuji OishiAbstract:The ion exchange of Cl- and OH- with F- in synthetic calcium Chlorapatite and calcium hydroxyapatite single crystals was investigated under hydrothermal conditions. The hydrothermal treatments were conducted using 5 and 10 M KF solutions, at temperatures of 500 and 600 °C under a constant internal pressure of 100 MPa, for intervals between 6 and 336 h. The ion exchange of Cl- in the Chlorapatite crystals proceeded faster than that of OH- in the hydroxyapatite crystals during hydrothermal treatments at 500 °C in 5 M KF solution. Under these conditions, the Chlorapatite crystals were completely converted to fluorapatite crystals. In contrast, the hydroxyapatite crystals were only partially converted to fluorapatite. In both cases, the topotaxial ion-exchange reaction was achieved by a mechanism of dissolution−precipitation of clusters. The partially and completely converted fluorapatite crystals had a characteristic texture, exhibiting tiny tunnels along the c axis of the crystals, and a thin layer of CaF2 ...
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Topotaxial replacement of Chlorapatite by hydroxyapatite during hydrothermal ion exchange
American Mineralogist, 1999Co-Authors: Kazumichi Yanagisawa, J.c. Rendón-angeles, Nobuo Ishizawa, Shuji OishiAbstract:Exchange of Cl - by OH - in synthesized Chlorapatite single crystals was investigated under hydro- thermal conditions. Hydrothermal treatments were performed at various temperatures from 200 to 500 °C, for intervals between 3 and 96 h in KOH or NaOH solutions. Ion exchange of Cl - in the Chlorapatite crystals was completed at low temperature (500 °C) for a short time (12 h) in 6.25 M KOH solution, and resulted in the formation of hydroxyapatite. The rate of ion exchange was accel- erated by increasing the reaction temperature and/or concentration of the alkaline solutions. That the converted crystals were single crystals of hydroxyapatite was confirmed by X-ray precession photo- graphs. The hydroxyapatite single crystals that formed from the Chlorapatite single crystals by the topotaxial ion exchange under alkaline hydrothermal conditions had a characteristic texture, exhibit- ing channels on the surfaces and tunnels inside, both along the c axis of the crystals. A dissolution and precipitation process is proposed for the ion-exchange reaction conducted under hydrothermal conditions.