scholarly journals Synthesis of Silica/Hydroxyapatite Nanocomposite by Mechanochemical Method

2021 ◽  
Author(s):  
Ahmed Hannora ◽  
M. M. Mostafa
Keyword(s):  
Calcium Phosphate ◽  
Biomedical Applications ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Suitable Material ◽  
Heat Treated ◽  
Phosphate Silicate ◽  
Ft Ir ◽  
Main Components ◽  
Apatite Lattice

Abstract Biocompatibility of Silica makes it a suitable material for biomedical applications. The main components of teeth and bones are calcium phosphate (CP). Hydroxyapatite (HA) is expected to be used in different fields not only in biomedical applications but also in agriculture as a fertilizer and pollution treatment. Various substitutions in the apatite lattice play a significant role in its properties. In the present work, Silica-50, 40, 30 and 25 mol.% Hydroxyapatite nanocomposites were prepared successfully by mechanochemical processing method. X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) indicated that silica stimulates the HA decomposition to β-tricalcium phosphate (β-TCP). XRD of heat-treated compacted sample at 1200oC confirmed β-TCP and calcium phosphate silicate phases formation. Mechanical properties decreased with decreasing HA content. Electrochemical impedance spectroscopy (EIS) results revealed that pure HA possess the highest resistivity to corrosion, while the silica/HA samples showed lower corrosion resistance. The polarization resistance increases with HA content.

Influence of Substrate Temperature in the Morphology and Microstructure of YSZ Films Obtained on LSM Porous Substrate via Spray Pyrolysis

2012 ◽  
Vol 727-728 ◽  
pp. 691-696 ◽  
Author(s):  
Tiago Falcade ◽  
Giselle Barbosa de Oliveira ◽  
Diego Pereira Tarragó ◽  
Vânia Caldas de Sousa ◽  
Célia de Fraga Malfatti
Keyword(s):  
Substrate Temperature ◽  
Spray Pyrolysis ◽  
Spray Pyrolysis Technique ◽  
Precursor Solution ◽  
Cubic Phase ◽  
Porous Substrate ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Ft Ir ◽  
Influence Of Substrate

Many studies have been reported in the literature related to YSZ films deposited on dense substrate or applied directly on the SOFC anode. However, there are not a lot of studies about the YSZ deposition on the cathode. The present work aims to obtain yttria-stabilized zirconia (YSZ), using the spray pyrolysis technique, for their application as electrolyte in solid oxide fuel cells (SOFC). The films were obtained from a precursor solution containing zirconium and yttrium salts, dissolved in ethanol and propylene glycol (1:1), this solution was sprayed onto a heated LSM porous substrate. The substrate temperature was varied in order to obtain dense and homogeneous films. After deposition, the films were heat treated, aiming to crystallize and stabilize the zirconia cubic phase. The films were characterized by Scanning Electron Microscopy (SEM), thermal analysis, X-ray diffraction and Fourier transform Infrared Spectroscopy (FT-IR).

scholarly journals Χαρακτηρισμός πολυμερικών επιστρώσεων με νανοπερίεκτες σε μέταλλα για την προστασία τους από διάβρωση σε θαλάσσιο περιβάλλον

2012 ◽  
Author(s):  
Ανδρόνικος Μπαλάσκας
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organically Modified Silicates ◽  
Organically Modified ◽  
Ft Ir ◽  
Scanningelectron Microscopy

Υβριδικές επιστρώσεις οργανικά τροποποιημένων πυριτικών ενώσεων και εποξειδικώνρητινών (Organically Modified Silicates, ORMOSILs – epoxy) εφαρμόστηκαν στο κράμααργιλίου 2024-Τ3 και σε γαλβανισμένο χάλυβα σε υψηλές θερμοκρασίες (Hot Dip GalvanizedSteel, HDGS) προκειμένου αυτές να προστατεύσουν τα υποστρώματα από τη διάβρωση. Για τηνβελτίωση της αντοχής των επιστρώσεων στην διάβρωση ενσωματώθηκαν στην πολυμερικήμήτρα νανοπεριέκτες από μολυβδαινικό δημήτριο (CeMo) και οξείδιο του τιτανίου (TiO2),καθώς και pH-ευαίσθητα οργανικά νανοδοχεία πληρωμένα με τους αναστολείς διάβρωσης 2-μερκαπτοβενζοθειαζόλιο, 8-υδροξυκινολίνη, 1H-βενζοτριαζολο-4-σουλφονικό οξύ καιεξαφλουοροτιτανικό οξύ.Οι υβριδικές επιστρώσεις εφαρμόστηκαν στο υπόστρωμα με τη διαδικασία εμβάπτισης.Η μορφολογία των επιστρώσεων εξετάστηκε με ηλεκτρονική μικροσκοπία σάρωσης (ScanningElectron Microscopy (SEM)). Η σύνθεση και η δομή τους μελετήθηκε με υπέρυθρηΦασματοσκοπία μετασχηματισμού Fourier (FT-IR) και με μικροανάλυση με φθορισμομετρίαακτίνων Χ (Energy Dispersive X-Ray Analysis (EDX)). H ηλεκτροχημική φασματοσκοπίασύνθετης αντίστασης (Electrochemical Impedance Spectroscopy, EIS), η dc-πόλωση (dcpolarization)και η μέτριση ανοικτού δυναμικού (open circuit potential, OCP) χρησιμοποιήθηκανγια την αξιολόγηση των αντι-διαβρωτικών ιδιοτήτων των επιστρώσεων. Τα αποτελέσματαέδειξαν ότι οι επιστρώσεις με πληρωμένα νανοδοχεία έχουν αυξημένες αντιδιαβρωτικέςιδιότητες συγκριτικά με τις υπόλοιπες επιστρώσεις εμφανίζοντας και ιδιότητες αυτο-θεραπείας.Τέλος, συντέθηκαν νανόσφαιρες οξειδίου του χαλκού (Cu2O), οι οποίεςχαρακτηρίστηκαν με SEM, ηλεκτρονική μικροσκοπία διερχόμενης δέσμης (ΤransmissionΕlectron Μicroscopy (TEM)) και περίθλαση ακτίνων Χ (X ray Diffraction (XRD)). Οινανόσφαιρες στη συνέχεια πληρώθηκαν με ουσίες που δρουν ως βιοκτόνα και ενσωματώθηκανσε βαφές εμπορίου και σε επιστρώσεις βασισμένες σε εποξειδικές ενώσεις και μελετήθηκε ηδράση τους ως αντιαποθετικά αντιδραστήρια. Τα αποτελέσματα έδειξαν ότι οι επιστρώσεις μεπληρωμένες νανόσφαιρες Cu2O είχαν μεγαλύτερη αποτελεσματικότητα σε σύγκριση με τιςβαφές εμπορίου με βιοκτόνα μετά από έκθεση σε θαλάσσιο περιβάλλον.

scholarly journals STARCH MEDIATED SYNTHESIS OF HYDROXYAPATITE NANOPARTICLE FOR BIOMEDICAL APPLICATIONS

2015 ◽  
Vol 2 (1) ◽  
pp. 15-17
Author(s):  
Indira J
Keyword(s):  
Biomedical Applications ◽  
Soluble Starch ◽  
Morphological Properties ◽  
Spherical Nanoparticles ◽  
Hydroxyapatite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Average Size ◽  
Controllable Size

Hydroxyapatite (HAP) nanoparticles with uniform morphologies and controllable size have been synthesized by template directed method. The environment and eco-friendly polysaccharide soluble starch is used as a template to regulate size and shape of the nanoparticles synthesized. Structural and morphological properties of as-synthesized hydroxyapatite nanoparticles have been examined through the techniques like Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD) and Scanning Electron Microscopy(SEM), respectively. The results indicate that the obtained particles are uniform discrete spherical nanoparticles. The average size of the hydroxyapatite nanoparticles were ranged from 45 to 60 nm.

Fe-Doped UiO-66 Combined with ZnIn2S4 for Adsorption and Degradation of RhB Under Visible Light

NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050089
Author(s):  
Litong Niu ◽  
Shaoping Hu ◽  
Yali Ma ◽  
Mingming Wang ◽  
Bolin Lv ◽  
...  
Keyword(s):  
Visible Light ◽  
Electrochemical Impedance ◽  
Diffuse Reflectance Spectroscopy ◽  
Photogenerated Electron ◽  
Impedance Spectrum ◽  
Solvothermal Reaction ◽  
Electrochemical Impedance Spectrum ◽  
X Ray Diffraction ◽  
One Pot ◽  
Ft Ir

Novel ZnIn2S4/FeUiO-66 (ZFeU) photocatalyst with different proportion of FeUiO-66 has been successfully prepared by a facile one-pot solvothermal reaction. The as-synthesized nanocomposites have been thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Brunauer–Emmett–Teller (BET) characterization, photoluminescence (PL) analysis and electrochemical impedance spectrum (EIS). The photocatalytic performance of ZFeU nanocomposites for the photodegradation of RhB under visible light irradiation was better than that of ZnIn2S4 and FeUiO-66 alone. The experiment results showed the 20% ZFeU nanocomposites had the best photocatalytic properties. At the same time, a probable mechanism was discussed and it was believed that introduction of FeUiO-66 on ZnIn2S4 would minimize the recombination of photogenerated electron-hole pairs, leading to the enhancement of the photocatalytic activity.

Study and Characterization of Powders Nanocomposites Calcium Phosphate/Silica-Gel (SiO2n) Obtained from Attrition Milling: For Biomedical Applications

2008 ◽  
Vol 396-398 ◽  
pp. 615-618
Author(s):  
Rodrigo Brandão ◽  
Fernando Pupio ◽  
Nelson Heriberto A. Camargo ◽  
E. Gemelli
Keyword(s):  
Calcium Phosphate ◽  
Silica Gel ◽  
Biomedical Applications ◽  
Bone Matrix ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Attrition Milling ◽  
Bone Calcium

The bioceramics nanostructured have made important characteristics in biomedical applications, especially the calcium phosphate ceramics. The aim of this work is synthesis and characterization of calcium phosphate and nanocomposites powders, the method of dissolution of CaO in liquid medium, precipitation and formation of bone calcium phosphate matrix, and nanocomposites by adding the solution of phosphoric acid (H3PO4). The nanocomposites powders were synthesized using as strengthening silica gel nanometer (20nm) at concentrations of 1%, 2%, 3% and 5% by volume and subjected to heat treatment to 900°C for 2 hours, seeking obtained HA (Hydroxyapatite). Later the bone matrix of calcium phosphate and nanocomposites powders were subjected from process attrition milling for 2 hours, by way of comparison. The studies characterizations were conducted through the technique of X-ray diffraction, scanning electron microscopy (SEM) and dilatometric test.

scholarly journals Valorization of Albedo Orange Peel Waste to Develop Electrode Materials in Supercapacitors for the Electric Industry

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Gladis G. Suárez ◽  
José A. Ramírez ◽  
Juan F. Castañón ◽  
Jorge A. Galavíz ◽  
Perla C. Meléndez
Keyword(s):  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Orange Peel ◽  
Activation Process ◽  
X Ray Diffraction ◽  
Electric Industry ◽  
X Ray ◽  
Orange Peel Waste ◽  
Ft Ir

This work proposes the use of albedo of orange peel in generation of carbon for applications in supercapacitors. For this, a comparison of compositional and electrochemical properties present in the carbons obtained of albedo, flavedo, and the complete orange peel was carried out. The morphology and composition of carbons obtained were analyzed by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), X-Ray Diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The synthetized carbons were not subjected to the activation process by chemical compounds to relate only the properties of orange peel parts with their electrochemical behaviour. All samples were tested by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The carbon obtained of albedo presented a superior specific capacitance (210 F/g) of the rest samples. The value of albedo-based carbon capacitance is comparable with works presented in the literature that used a whole orange peel with chemical activators. In this way, it is possible to obtain large capacitances using only a part of orange peel (albedo). Thus, the importance of this study is that the albedo can be proposed as a material applied to electrodes for supercapacitors while the flavedo can be used in food industry or for oil extraction.

scholarly journals Corrosion Resistance of Heat-Treated Ni-W Alloy Coatings

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1172
Author(s):  
Magdalena Popczyk ◽  
Julian Kubisztal ◽  
Andrzej Szymon Swinarew ◽  
Zbigniew Waśkiewicz ◽  
Arkadiusz Stanula ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Active Surface ◽  
Active Surface Area ◽  
X Ray Diffraction ◽  
Kelvin Probe ◽  
Research On Evaluation ◽  
Heat Treated ◽  
Electrochemically Active

The paper presents research on evaluation of corrosion resistance of Ni-W alloy coatings subjected to heat treatment. The corrosion resistance was tested in 5% NaCl solution by the use of potentiodynamic polarization technique and electrochemical impedance spectroscopy. Characteristics of the Ni-W coatings after heat treatment were carried out using scanning electron microscopy, scanning Kelvin probe technique and X-ray diffraction. Suggested reasons for the improvement of properties of the heat treated Ni-W coating, obtained at the lowest current density value (125 mA∙cm−2), are the highest tungsten content (c.a. 25 at.%) as well as the smallest and the most homogeneous electrochemically active surface area.

scholarly journals Surface Treatment of Zn-Mn-Mg Alloys by Micro-Arc Oxidation in Silicate-Based Solutions with Different NaF Concentrations

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4289
Author(s):  
Shineng Sun ◽  
Guo Ye ◽  
Ziting Lu ◽  
Yuming Weng ◽  
Guofeng Ma ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Corrosion Behavior ◽  
Biomedical Applications ◽  
Electrochemical Impedance ◽  
Mg Alloys ◽  
X Ray Diffraction ◽  
Submicron Scale ◽  
Micro Arc Oxidation ◽  
Hank’S Solution ◽  
Zn Alloys

Newly developed Zn-Mn-Mg alloys can be invoked as biomedical materials because of their excellent mechanical properties. However, the corrosion behavior of Zn-Mn-Mg alloys was still lacking in research. It had grown to be a hot research topic to improve the corrosion behavior of Zn alloys by surface treatment to meet the application of degradable Zn alloys in biomedical applications. Micro arc oxidation (MAO) is a simple and effective method to improve the corrosion behavior of the alloy. MAO coatings were successfully prepared on the surface of Zn-Mn-Mg alloys by MAO in silicate-based solutions with different NaF concentrations. The microstructure and phase composition of MAO coatings prepared on Zn-Mn-Mg alloys with different NaF concentrations in the electrolyte was examined by a scanning electron microscope and X-ray diffraction. The results showed that the MAO coatings are porous and mainly composed of ZnO. With the increasing NaF concentration in the electrolyte, the average thickness increases. The distribution of the micro/nanopores was uniform, and the pore size ranged from the submicron scale to several micrometers after MAO treatment in the electrolyte containing different concentrations of NaF. Potential dynamic polarization curves and electrochemical impedance spectroscopy were employed to assess the corrosion behavior of MAO coatings in Hank’s solution. The highest corrosion rate can be achieved after MAO treatment, with an electrolyte concentration of 1.5 g/L NaF in Hank’s solution. These results indicated that MAO coating can accelerate the corrosion resistance of a Zn-Mn-Mg alloy.

scholarly journals Diopside Glass-Ceramics for Dental and Biomedical Applications

2014 ◽  
Vol 96 ◽  
pp. 15-20 ◽  
Author(s):  
Jamila Almuhamadi ◽  
Natalia Karpukhina ◽  
Mike Cattell
Keyword(s):  
Molten Glass ◽  
Water Glass ◽  
Biomedical Applications ◽  
Glass Ceramics ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Step Heat Treatment ◽  
Glass Compositions

A series of glass compositions with varying equimolar amounts of Na2O:Al2O3 were designed using Appen factors. High purity batch reagents were ball milled for 30 min and transferred to Pt/Rh crucible and melted in an electric furnace (EHF1700, Lenton, UK) at high temperatures then held for 90 min. The molten glass was poured into a graphite mould, annealed at 50°C below the glass transition temperature for 1h and the remaining glass was quenched into water. Glass frits were crushed and ball milled into powders with different particle sizes. Glass powders (PS<125μm) were heat-treated via two-step heat treatment cycles and air quenched. Experimental glasses and glass-ceramics were characterised using X-Ray Diffraction (XRD), Dilatometry, Scanning Electron Microscopy (SEM) and solid state Nuclear Magnetic Resonance (NMR).

scholarly journals Electrochemical Property Assessment of Pr2CuO4 Submicrofiber Cathode for Intermediate-Temperature Solid Oxide Fuel Cells

2016 ◽  
Vol 13 (1) ◽  
Author(s):  
Ting Zhao ◽  
Li-Ping Sun ◽  
Qiang Li ◽  
Li-Hua Huo ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Reduction Reaction ◽  
Intermediate Temperature ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Rate Limiting Step ◽  
Heat Treated ◽  
Porous Microstructure ◽  
Ft Ir ◽  
Property Assessment

The Pr2CuO4 (PCO) submicrofiber precursors are prepared by electrospinning technique and the thermo-decomposition procedures are characterized by thermal gravity (TG), X-ray diffraction (XRD), Fourier transform infrared spectoscopy (FT-IR), and scanning electron microscopy (SEM), respectively. The fibrous PCO material was formed by sintering the precursors at 900 °C for 5 hrs. The highly porous PCO submicrofiber cathode forms good contact with the Ce0.9Gd0.1O1.95 (CGO) electrolyte after heat-treated at 900 °C for 2 hrs. The performance of PCO submicrofiber cathode is comparably studied with the powder counterpart at various temperatures. The porous microstructure of the submicrofiber cathode effectively increases the three-phase boundary (TPB), which promotes the surface oxygen diffusion and/or adsorption process on the cathode. The PCO submicrofiber cathode exhibits an area specific resistance (ASR) of 0.38 Ω cm2 at 700 °C in air, which is 30% less than the PCO powder cathode. The charge transfer process is the rate limiting step of the oxygen reduction reaction (ORR) on the submicrofiber cathode. The maximum power densities of the electrolyte-support single cell PCO|CGO|NiO-CGO reach 149 and 74.5 mW cm−2 at 800 and 700 °C, respectively. The preliminary results indicate that the PCO submicrofiber can be considered as potential cathode for intermediate temperature solid fuel cells (IT-SOFCs).

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