Highly Porous Hydroxyapatite Ceramics for Engineering Applicatios

2010 ◽  
Vol 63 ◽  
pp. 408-413 ◽  
Author(s):  
Hrvoje Ivankovic ◽  
Sebastijan Orlic ◽  
Dajana Kranzelic ◽  
Emilija Tkalcec
Keyword(s):  
Average Length ◽  
Average Diameter ◽  
Ftir Analysis ◽  
X Ray Diffraction ◽  
Gas Cell ◽  
Porous Hydroxyapatite ◽  
Hydroxyapatite Ceramics ◽  
Heat Treated ◽  
Hydrothermal Transformation ◽  
Highly Porous

Highly porous hydroxyapatite (Ca10(PO4)6(OH)2, HA) was prepared through hydrothermal (HT) transformation of aragonitic cuttlefish bones (Seppia Officinalis L. Adriatic Sea) in the temperature range from 140°C to 220°C for 20 minutes to 48 hours. Mechanism of hydrothermal transformation of bones was investigated by DTA/TG analyzer coupled online with FTIR spectrometric gas cell equipment (DTA-TG-EGA-FTIR analysis), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). DTA-TG-EGA-FTIR analysis have shown the release of CO2 at about 400°C, 680°C and 990°C. The first release could be attributed to organics not completely removed from the heat treated bones, and the second release to decomposition of unconverted aragonite, whereas, the third one could be attributed to CO3 2– groups incorporated in the structure of HA. The interconnecting porous morphology of the starting material (aragonite) was maintained during the HT treatment. The formation of dandelion-like HA spheres with diameter from 3 to 8 μm were observed, which further transformed into nanoplates and nanorods with an average diameter of about 200-300 nm and an average length of about 8-10 μm.

Reinforcing of Porous Hydroxyapatite Ceramics with Hydroxyapatite Fibres for Enhanced Bone Tissue Engineering

2011 ◽  
Vol 10 ◽  
pp. 67-73 ◽  
Author(s):  
Lie Feng Liang ◽  
Xiao Yi Han ◽  
Xiao Cai Yan ◽  
Jie Weng
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Test Machine ◽  
Porous Structures ◽  
X Ray Diffraction ◽  
Porous Hydroxyapatite ◽  
Hydroxyapatite Ceramics ◽  
Ceramic Implants

Porous hydroxyapatite (HA) ceramic implants have attracted attention in bone tissue engineering due to their excellent bioactivity and biocompatibility due to their chemical similarity with the mineral component of natural bone. Unfortunately, HA when is formed into porous structures exhibits very low compression strength. In this study, fabrication of porous HA ceramic scaffolds containing HA fibers is presented. The primary aim of the study is to improve mechanical properties of the scaffold by introducing the fiber with uniform component relative to the scaffold. Scanning electron microscopy was used to observe the surface morphology and pore size of the scaffold. X-ray diffraction (XRD) was used to detect the phase composition and crystallinity of the scaffold. The compressive strength was determined using a universal material test machine. The results and the characterizations demonstrate the addition of HA fiber could enhance the uniformity of mechanical properties among samples and also the strength for a given open porosity.

scholarly journals Preparation of Silver Nanostructures from Bicontinuous Microemulsions

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
M. A. Pedroza-Toscano ◽  
M. Rabelero-Velasco ◽  
R. Díaz de León ◽  
H. Saade ◽  
R. G. López ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Average Length ◽  
Sodium Dodecylsulfate ◽  
Average Diameter ◽  
Silver Nanostructures ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Reverse Microemulsions

Precipitation of silver nanoparticles at 70°C was carried out by dosing a 1.3 M sodium borohydride aqueous solution over bicontinuous microemulsions formed with a mixture of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and sodium dodecylsulfate (SDS) as surfactants, a 0.5 M silver nitrate aqueous solution, and toluene. Weight ratios of 2.5/1 and 3/1 AOT/SDS were used in the precipitation reactions. Silver nanoparticles were characterized by transmission electronic microscopy, X-ray diffraction, and atomic absorption spectroscopy. A mixture of isolated spheroidal nanoparticles (≈15 wt.%) with an average diameter around 10 nm and wormlike structures (≈85 wt.%) with an average length close to 480 nm and an average diameter ca. 40 nm was obtained, regardless of the AOT/SDS ratio. Higher yields were obtained compared with those reported when reverse microemulsions were employed. Formation of wormlike structures was ascribed to one-dimensional aggregation of crystal and particles within the channels of bicontinuous microemulsions, which performed as templates.

Facile synthesis and electrical characteristics of n-SnO2/p-NiO nanowire heterojunctions

2019 ◽  
Vol 29 (1) ◽  
pp. 77 ◽  
Author(s):  
Dang Thi Thanh Le ◽  
Chu Manh Hung
Keyword(s):  
Average Length ◽  
Chemical Vapor ◽  
Average Diameter ◽  
Energy Structure ◽  
Pure Sno2 ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
Xrd Patterns ◽  
Hydrothermal Methods ◽  
Nanowire Heterojunctions

In the current work, we report a facile synthesis of n-SnO2/p-NiO nanowire heterojunctions by a drop-coating approach. The pure SnO2 and NiO nanowires (NWs) were grown by chemical vapor deposition (CVD) and hydrothermal methods, respectively. Morphology, composition and crystal structures of the NWs and heterojunctions were investigated by means of field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The data showed that SnO2 NWs were grown with their average diameter of 200 nm and length of about 10 mm. The NiO NWs were also synthesized with a shorter average length and smaller average diameter compared to those of the SnO2 NWs. The EDS results indicated no impurity present in both SnO2 and NiO NWs. The XRD patterns pointed out the tetragonal rutile and cubic structures of SnO2 and NiO, respectively. Interestingly, electrical properties of the NWs and heterojunctions were studied through the Keithley 2602A sourcemeter-based I-V characterizations. The results confirm the nature of the metal semiconducting oxides. The formation of the n-SnO2/p-NiO heterojunctions was certified through the rectifying behavior of the I-V curves with the rectification ratio of about 5 at ± 3V and 350 oC. The potential energy barrier between the NWs was also estimated to be about 1.16 eV. The band energy structure was also proposed to get insight into characteristics of the n-SnO2/p-NiO heterojunction.

Magnetic Properties of Mg0.4Ca0.6Fe2O4 Nanoparticles Synthesized by Sol-Gel Method for Hyperthermia Treatment

2014 ◽  
Vol 631 ◽  
pp. 193-197
Author(s):  
A.M. Escamilla-Pérez ◽  
D.A. Cortés-Hernández ◽  
J.M. Almanza-Robles ◽  
D. Mantovani ◽  
P. Chevallier
Keyword(s):  
Magnetic Properties ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Hyperthermia Treatment ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures ◽  
Xrd Patterns

Powders of Mg0.4Ca0.6Fe2O4were prepared by sol-gel using ethylene glycol and Mg, Ca and Fe nitrates as starting materials. Those powders were heat treated at different temperatures (300, 400, 500 and 600 °C) for 30 min. The materials obtained were characterized by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The Ca-Mg ferrite with the most appropriate magnetic properties was further analyzed by transmission electron microscopy (TEM). The heating capability of the nanoferrites was also tested via magnetic induction. The XRD patterns of these Ca-Mg ferrites showed a cubic inverse spinel structure. Furthermore, neither traces of hematite nor orthorhombic Ca ferrite phases were detected. Moreover, all the Ca-Mg ferrites are superparamagnetic and the particle size distribution of these Ca-Mg magnetic nanoparticles exhibits an average diameter within the range of 10-14 nm. The needed temperature for hyperthermia treatment was achieved at around 12 min.

Preparation of Highly Porous Hydroxyapatite Ceramics from Cuttlefish Bone

2006 ◽  
Vol 49 ◽  
pp. 142-147 ◽  
Author(s):  
H. Ivankovic ◽  
G. Gallego Ferrer ◽  
E. Tkalcec ◽  
M. Ivankovic
Keyword(s):  
Tissue Engineering ◽  
Specific Surface ◽  
Pore Volume ◽  
Engineering Application ◽  
Hollow Structure ◽  
Total Pore Volume ◽  
Tissue Engineering Application ◽  
Porous Hydroxyapatite ◽  
Hydroxyapatite Ceramics ◽  
Highly Porous

Scaffold of hydroxyapatite for further tissue-engineering application was produced by hydrothermal treatment of cuttlefish bone originated aragonite at 200°C. Aragonite (CaCO3) monoliths were completely transformed into hydroxyapatite after 48 hours of HT treatment. The substitution of CO3- groups predominantly into the PO4 3- sites of the Ca10(PO4)6(OH)2 structure was suggested by FTIR spectroscopy. SEM micrographs have shown that the interconnected hollow structure with pillars connecting parallel lamellae in cuttlefish bone is maintained after conversion. Specific surface area (SBET) and total pore volume increased and mean pore size decreased by HT treatment.

scholarly journals Interconnected porous hydroxyapatite ceramics for bone tissue engineering

2008 ◽  
Vol 6 (suppl_3) ◽  
Author(s):  
Hideki Yoshikawa ◽  
Noriyuki Tamai ◽  
Tsuyoshi Murase ◽  
Akira Myoui
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Animal Experiments ◽  
Average Diameter ◽  
Dimensional Structure ◽  
Uniform Size ◽  
Porous Hydroxyapatite ◽  
Hydroxyapatite Ceramics ◽  
Novel Scaffold

Several porous calcium hydroxyapatite (HA) ceramics have been used clinically as bone substitutes, but most of them possessed few interpore connections, resulting in pathological fracture probably due to poor bone formation within the substitute. We recently developed a fully interconnected porous HA ceramic (IP-CHA) by adopting the ‘foam-gel’ technique. The IP-CHA had a three-dimensional structure with spherical pores of uniform size (average 150 μm, porosity 75%), which were interconnected by window-like holes (average diameter 40 μm), and also demonstrated adequate compression strength (10–12 MPa). In animal experiments, the IP-CHA showed superior osteoconduction, with the majority of pores filled with newly formed bone. The interconnected porous structure facilitates bone tissue engineering by allowing the introduction of mesenchymal cells, osteotropic agents such as bone morphogenetic protein or vasculature into the pores. Clinically, we have applied the IP-CHA to treat various bony defects in orthopaedic surgery, and radiographic examinations demonstrated that grafted IP-CHA gained radiopacity more quickly than the synthetic HA in clinical use previously. We review the accumulated data on bone tissue engineering using the novel scaffold and on clinical application in the orthopaedic field.

Synthesis and Structural Characterization of Mo-Ni-W Oxide Nanostructures

2008 ◽  
Vol 8 (6) ◽  
pp. 2983-2989 ◽  
Author(s):  
F. Paraguay-Delgado ◽  
R. Huirache-Acuña ◽  
M. Jose-Yacaman ◽  
G. Alonso-Nuñez
Keyword(s):  
Electron Microscopy ◽  
Average Length ◽  
Average Diameter ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Nanostructures ◽  
Transmission Electron ◽  
Segregated Structure

In this work, we report the synthesis and characterization of Mo-Ni-W oxides. The precursor was prepared from an aqueous solution of ammonium heptamolibdate, ammonium metatungstate, and nickel nitrate with an atomic ratio of 1:1:1 (Mo:W:Ni). The solution was then transferred to a Teflon-lined stainless steel autoclave and heated to 200 °C and left at this temperature for 48 h. The resulting material was then washed and dried. The morphology and elemental composition were studied by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The porosity was studied by the Brunauer, Emmett, and Teller method. The materials synthesized at 200 °C remained amorphous and had a specific surface area of 114 m2/g with pore size of 34 Å. The average length was 1 μm and the average diameter was 60 nm. The crystalline phase of synthesized material corresponded to W0.4Mo0.6O3 and WO3. After annealing at 550 °C for two hours, the material was polycrystalline with a segregated structure of MoO3, WO3; NiMoO4 was observed. The sublimation of the molybdenum oxide was evident when annealed at 900 °C for two hours and finally two crystalline phases of material remained; roundish WO3 and elongated particles of NiWO4.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

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