scholarly journals Lab and Pilot-Scale Synthesis of MxOm@SiC Core–Shell Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 649 ◽  
Author(s):  
Àngela Ribes ◽  
Santiago Sánchez-Cabezas ◽  
Andy Hernández-Montoto ◽  
Luis A. Villaescusa ◽  
Elena Aznar ◽  
...  
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Scale Up ◽  
Pilot Scale ◽  
Core Shell ◽  
Matrix Composites ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Scanning Transmission ◽  
Core Shell Nanoparticles

The addition of light ceramic particles to bulk technological materials as reinforcement to improve their mechanical properties has attracted increasing interest in the last years. The metal matrix composites obtained using nanoparticles have been reported to exhibit an improvement of their properties due to the decrease in the size of the ceramic additives to the nanoscale. Additionally, important effects such as the dispersion of the nanoparticles, wettability, and low reactivity can be controlled by the modification of the nanoparticles’ surface. In this work, we present the preparation of core–shell MxOm@SiC nanoparticles with different shell compositions. The accurate and reproducible preparation is developed both at the lab and pilot scale. The synthesis of these core–shell nanoparticles and their scale-up production are fundamental steps for their industrial use as additives in metal matrix composites and alloys. Powder X-ray diffraction and energy dispersive X-ray (EDX) coupled with scanning transmission electron microscopy (STEM) are used to corroborate the formation of the core–shell systems, whereas line scan-EDX analysis allows measuring the average shell thickness.

scholarly journals Core/Shell Structure of TiO2-Coated MWCNTs for Thermal Protection for High-Temperature Processing of Metal Matrix Composites

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Laura Angélica Ardila Rodriguez ◽  
Dilermando Nagle Travessa
Keyword(s):  
Thermal Stability ◽  
Metal Matrix Composites ◽  
Shell Structure ◽  
Metal Matrix ◽  
Thermal Protection ◽  
Oxidation Stability ◽  
Core Shell ◽  
Matrix Composites ◽  
X Ray ◽  
Core Shell Structure

The production of metal matrix composites with elevated mechanical properties depends largely on the reinforcing phase properties. Due to the poor oxidation resistance of multiwalled carbon nanotubes (MWCNTs) as well as their high reactivity with molten metal, the processing conditions for the production of MWCNT-reinforced metal matrix composites may be an obstacle to their successful use as reinforcement. Coating MWCNTs with a ceramic material that acts as a thermal protection would be an alternative to improve oxidation stability. In this work, MWCNTs previously functionalized were coated with titanium dioxide (TiO2) layers of different thicknesses, producing a core-shell structure. Heat treatments at three different temperatures (500°C, 750°C, and 1000°C) were performed on coated nanotubes in order to form a stable metal oxide structure. The MWCNT/TiO2 hybrids produced were evaluated in terms of thermal stability. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (RS), and X-ray photoelectron spectroscopy (XPS) were performed in order to investigate TiO2-coated MWCNT structure and thermal stability under oxidative atmosphere. It was found that the thermal stability of the TiO2-coated MWCNTs was dependent of the TiO2 layer morphology that in turn depends on the heat treatment temperature.

Energy-dispersive X-ray spectroscopy for an atomic-scale quantitative analysis of Pd–Pt core-shell nanoparticles

Microscopy ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 26-30
Author(s):  
Shin Inamoto ◽  
Yuji Otsuka
Keyword(s):  
Quantitative Analysis ◽  
Shell Thickness ◽  
Dark Field ◽  
Atomic Scale ◽  
Energy Dispersive ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Scanning Transmission ◽  
Core Shell Nanoparticles

Abstract The properties of core-shell nanoparticles, which are used for many catalytic processes as an alternative to platinum, depend on the size of both the particle and the shell. It is thus necessary to develop a quantitative method to determine the shell thickness. Pd–Pt core-shell particles were analyzed using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDX). Quantitative EDX line profiles acquired from the core-shell particle were compared to four core-shell models. The results indicate that the thickness of the Pt shell corresponds to two atomic layers. Meanwhile, high-angle annular dark-field STEM images from the same particle were analyzed and compared to simulated images. Again, this experiment demonstrates that the shell thickness was of two atomic layers. Our results indicate that, in small particles, it is possible to use EDX for a precise atomic-scale quantitative analysis.

scholarly journals Synthesis and Advanced Characterization of Polymer-Protein Core-Shell Nanoparticles

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 730
Author(s):  
Erik Sarnello ◽  
Tao Li
Keyword(s):  
Particle Size ◽  
Small Angle ◽  
Core Shell ◽  
Assembly Process ◽  
Shell Nanoparticles ◽  
X Ray ◽  
X Ray Scattering ◽  
Wide Range ◽  
Core Shell Nanoparticles ◽  
Ray Scattering

Enzyme immobilization techniques are widely researched due to their wide range of applications. Polymer–protein core–shell nanoparticles (CSNPs) have emerged as a promising technique for enzyme/protein immobilization via a self-assembly process. Based on the desired application, different sizes and distribution of the polymer–protein CSNPs may be required. This work systematically studies the assembly process of poly(4-vinyl pyridine) and bovine serum albumin CSNPs. Average particle size was controlled by varying the concentrations of each reagent. Particle size and size distributions were monitored by dynamic light scattering, ultra-small-angle X-ray scattering, small-angle X-ray scattering and transmission electron microscopy. Results showed a wide range of CSNPs could be assembled ranging from an average radius as small as 52.3 nm, to particles above 1 µm by adjusting reagent concentrations. In situ X-ray scattering techniques monitored particle assembly as a function of time showing the initial particle growth followed by a decrease in particle size as they reach equilibrium. The results outline a general strategy that can be applied to other CSNP systems to better control particle size and distribution for various applications.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

Core-Shell SiO2/Ag Composite Spheres Prepared by Electrical Exploding Wire Plasma Technique: Synthesis and Characterization

2021 ◽  
Vol 19 (10) ◽  
pp. 82-88
Author(s):  
Duaa A. Uamran ◽  
Qasim Hassan Ubaid ◽  
Hammad R. Humud
Keyword(s):  
Laser Pulse ◽  
Laser Pulses ◽  
Structural Features ◽  
Optical Absorption Spectroscopy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Photocatalytic Activities ◽  
Core Shell Nanoparticles

Core-shell nanoparticles (SiO2/Ag) were manufactured by using a two-step process: Electric detonation of Ag. Wire in colloidal solution particles then by using laser pulses, nanoparticles are released. The structural features of these nanoparticles were checked by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The (XRD) study showed the progressive coverage of SiO2/Ag by nanoparticles according to the energies of the laser pulse. Measurements of morphology and EDX confirmed the Core/shell structure with particle size at the nano level. It confirmed that preliminary analysis consists of a SiO2 core and an Ag shell from FESEM. The surface of the microscopic balls (SiO2) has been covered completely and homogeneously with Ag nanoparticles, Moreover, Ultraviolet-Visible, and by optical absorption spectroscopy, the Nanoparticles with core crust SiO2/Ag showed excellent photocatalytic activities at various concentrations and laser pulse energy.

X-ray welding of metal-matrix composites

1997 ◽  
Vol 68 (6) ◽  
pp. 2550-2553 ◽  
Author(s):  
Richard A. Rosenberg ◽  
Qing Ma ◽  
William Farrell ◽  
Mark Keefe ◽  
Derrick C. Mancini
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Composites ◽  
X Ray

The Preparation and Characteristic of Superparamagnetic Core/Shell Nanoparticles

2013 ◽  
Vol 274 ◽  
pp. 432-435
Author(s):  
Hong Xia Shen ◽  
Zheng Zhi Yin ◽  
Qiong Cheng
Keyword(s):  
Biomedical Applications ◽  
Superparamagnetic Nanoparticles ◽  
Bioactive Molecules ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Vibration Sample Magnetometer ◽  
Diffraction Patterns ◽  
Core Shell Nanoparticles

Superparamagnetic core/shell nanoparticles have been prepared successfully by the reduction of Au3+ onto the surface of superparamagnetic nanoparticles. The core/shell nanoparticles were characterized by Transmission electron microscopy (TEM), X-ray powder diffraction patterns (XRD), UV–vis spectrophotometer, Vibration Sample Magnetometer(VSM) and micro-confocal Raman system. The results revealed that the prepared core/shell nanoparticles were covered by Au shell. These superparamagnetic nanoparticles can be highly sensitively detected and afford new opportunities for biomedical applications through chemical bonding of bioactive molecules with the Au shell of nanoparticles.

Characterization of Metal Matrix Composites by Synchrotron Refraction Computed Topography

2010 ◽  
Vol 638-642 ◽  
pp. 967-972
Author(s):  
Bernd R. Müller ◽  
Axel Lange ◽  
M. Harwardt ◽  
M.P. Hentschel
Keyword(s):  
Computed Tomography ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
High Performance ◽  
Three Dimensional ◽  
Matrix Composites ◽  
X Rays ◽  
X Ray ◽  
Surface And Interface ◽  
Federal Institute

X-ray computed tomography is an important tool for evaluating the three dimensional microstructure of modern materials non-destructively. To resolve material structures in the micrometre range and below high brilliance synchrotron radiation has to be taken. But materials of low absorption or mixed phases show a weak absorption contrast at there interfaces. A Contrast enhancement can be achieved by exploiting the refraction of X-rays at interfaces. This technique was developed and applied at the NDT department of the Federal Institute for Materials Research and Testing (BAM) during the last decade. It meets the actual demand for improved non-destructive characterisation of high performance composites, ceramics and other low density materials and components. The technique is based on Ultra Small Angle Scattering (USAXS) by micro structural elements causing phase related effects like refraction and total reflection at a few minutes of arc as the refractive index of X-rays is nearly unity. The extraordinary refraction contrast of inner surfaces is far beyond absorption effects and hence especially useful for materials of low absorption or mixed phases, showing similar X-ray absorption properties. Crack orientation and fibre-matrix debonding in plastics, polymers, ceramics and metal-matrix-composites after cyclic loading and hydro thermal aging can be visualized. By combining the refraction technique with the computed tomography technique the three dimensional imaging of the micro structure of the materials is obtained. In most cases the investigated inner surface and interface structures correlate to mechanical properties. Recent results with a sub-micrometer resolution will be presented.

Sign in / Sign up

Export Citation Format

Share Document