Thermal morphological evolution of platinum nano-particles in Pt–Al2O3 nano-composites

2005 ◽  
Vol 344 (1) ◽  
pp. 57-63 ◽  
Author(s):  
M. Maaza ◽  
O. Nemraoui ◽  
C. Sella ◽  
J. Lafait ◽  
A. Gibaud ◽  
...  
2021 ◽  
Vol 13 (3) ◽  
pp. 473-480
Author(s):  
Yihan Jin ◽  
Xi Luo ◽  
Jinglin Zhang ◽  
Dongliang Zhao ◽  
Kewei Gao

Micro-emulsion method is adopted to synthesis rGO-Fe3O4-PANI (reduced graphene oxide-Fe3O4-polyaniline) ternary nano-composites. With the different contents of aniline (0.1 g, 0.2 g, 0.3 g) added in production, the corresponding final products are named as sample 1, sample 2, sample 3, respectively. The results of TEM indicate that the mean size of Fe3O4 nano-particles is 14 nm and they are anchored onto rGO slice. There are some PANI polymer wrinkles distributed on the rGO surface uniformly. The electro-magnetic data demonstrate that sample 1 possess a great enhancement of the electro-magnetic wave absorption abilities and frequency bandwidth among the three samples. The RLmin (minimum reflection loss) value of sample 1 is -44.16 dB at 4.29 GHz with 5 mm coating thickness and 1.77 GHz (3.72-4.94 GHz, 13.33-13.88 GHz) frequency bandwidth (RL <italic/> -10 dB). We can believe that this kind of nano-composites will have a promising application in the future.


2015 ◽  
Vol 1769 ◽  
Author(s):  
A. Crespo-Sosa ◽  
P.E. Mota-Santiago ◽  
J.L. Jiménez-Hernández ◽  
H.G. Silva-Pereyra ◽  
E.V. García-Ramírez ◽  
...  

ABSTRACTSapphire is best known for its hardness that makes it ideal for many mechanical and optical applications, but its resistance to radiation damage and its optical properties, combined with metallic nano-particles, make it promising for future opto-electronic and plasmonic devices. In this paper, we present an overview of our work on the fabrication of metallic nano-particles embedded in synthetic sapphire by means of ion implantation, thermal annealing and high energy ion irradiation. We show that we can have control over the amount and size of the nano particles formed inside the matrix by carefully choosing the parameters during the preparation process. Furthermore, we show that anisotropic nano particles can be obtained by an adequate high energy ion irradiation of the originally spherical nano particles. We also have studied the linear and non-linear optical properties of these nano-composites and have confirmed that they are large enough for future applications.


2020 ◽  
Vol 21 (3) ◽  
pp. 307 ◽  
Author(s):  
Pradyut Kumar Swain ◽  
Kasinath Das Mohapatra ◽  
Ratnakar Das ◽  
Ashok Kumar Sahoo ◽  
Amlana Panda

The current research paper discusses the characterization and machining (turning) operation of aluminium (Al) and silicon carbide nano particle (SiCp) nano composite. The paper reveals proper distribution of silicon carbide nano particles (25nm) with aluminium metal matrix. Initially, tensile test has been carried on metal matrix nano composite to study its different properties. It was noticed that the properties of Al-SiCp increases by increasing the weight percentage of SiCp. Viker hardness test has also been conducted to find out the hardness of metal matrix nano composites. Different techniques i.e. Optical microscopy EDX-Analysis were utilized to find out various ingredients of the nano-composite material. The experimental study was carried out using Taguchi L16 orthogonal array by taking three different factors at four different levels each. The response parameters i.e. flank wear of coated carbide insert and surface roughness of Al-SiCp has been optimized by using Principal Component Analysis (PCA). Various graphs like main effect plot and normal probability plot have been plotted and studied properly. Different optical images of coated insert carbide tools (Insert CNMG 12040822TN 6010) at different runs were conducted to visualize the effects of process and response parameters. From the ANOVA table, it was found that cutting speed as well as depth of cut are found to the most vital parameters in influencing the responses for VBc and depth of cut and feed are found to the most significant parameters in influencing the responses for Ra.


Author(s):  
Rudresh B M ◽  
Ravikumar B N ◽  
Madhu D ◽  
Lingesh B V

This article deals with the combined effect of micro and nano fillers on mechanical, thermal and morphological behavior of glass-basalt hybrid composites (GB). Three material systems were selected for the study: glass-basalt fiber reinforced 80 wt. % PA66 – 20 wt. % PTFE blend (GB), GB/Micro fillers (MoS2, SiC, Al2O3) (GBM) and GBM/nano fillers (TiO2) (GBN). It has been revealed from the experimentation that the effect of micro fillers deteriorated the mechanical behavior of micro composites (GBM). But the combined effect of micro and nano fillers slightly impaired the mechanical behavior of nano composites. The synergistic effect of micro and nano fillers constrained the loss of strength of nano composites. But the impact strength of nano composites has been improved due to hybrid fillers effect. The hybrid effect of fillers significantly improved the thermal stability of nano composites. Further, it is observed from the morphology that the fractured surfaces were characterized by fiber pull out and fiber overlapping, severe deformation and agglomeration of nano particles.


2015 ◽  
Vol 9 (11) ◽  
pp. 153 ◽  
Author(s):  
Nawal Ezzat Abdul-latiff ◽  
Akeel Dhahir Subhi ◽  
Marwan Basil Hussein

<p>In the present work, Al<sub>2</sub>O<sub>3</sub>/A356<sub> </sub>nano composites with different Al<sub>2</sub>O<sub>3</sub> nano sizes (10 and 20 nm) and weight percentages (1 and 2 wt.%) have been prepared using rheocasting technique and followed by hot deformation at 250 °C with different ratios (30 and 40%). Pin on disc wear test was used to study wear behavior of prepared Al<sub>2</sub>O<sub>3</sub>/A356<sub> </sub>nano composites while scanning electron microscopy used to build up the wear mechanism. The results showed that the hot deformed nano Al<sub>2</sub>O<sub>3</sub> /A356 composites have lower wear rate compared with non deformed one. Furthermore, with increasing the particle size and percentage of Al<sub>2</sub>O<sub>3</sub> nano particles, wear rate decreased. The optimal result was achieved at the nano-composite containing 20 nm Al<sub>2</sub>O<sub>3</sub> particles after hot deformation with ratio of 40%. SEM studies of the worn surfaces of nano composites showed that the main wear mechanism was oxidative in conjunction with metallic one.</p>


2018 ◽  
Vol 83 (1) ◽  
pp. 75-91 ◽  
Author(s):  
Fathie Kundie ◽  
Che Azhari ◽  
Zainal Ahmad

This research investigated the effects of alumina (Al2O3) micro- and nano-particles on poly(methyl methacrylate) (PMMA) denture base. Al2O3 was surface treated using (3-methacryloxypropyl)trimethoxysilane (?-MPS), added to methyl methacrylate (MMA), and mixed with PMMA powder. The filler volume fractions in the micro-composites were 0.5, 1, 2, 5 and 7 wt. %, whereas those in the nano-composites were 0.13, 0.25, 0.5, 1, 2 and 5 wt. %. The treated fillers were examined using Fourier transform infrared spectroscopy (FTIR). The influence of filler size and loading on mechanical properties was studied using fracture toughness and flexural tests. The thermal stability of the PMMA/Al2O3 composites was investigated using thermogravimetric analysis (TGA). In addition, the water absorption and solubility characteristic of the prepared composites was also investigated. The FTIR spectra showed new absorption bands, indicating the occurrence of surface modifications. Both micro- and nanoscale particles showed increased fracture toughness. The maximum value of 2.02 MPa?m1/2 was achieved with the addition of 0.5 wt. % nano-Al2O3, which accounts for a 39 % increase. In contrast to the flexural strength, the flexural modulus improved with increasing filler content. The micro-composites showed higher thermal stability than nano-composites. The water absorption and solubility of the prepared composites were slightly higher than those of the control. The use of low concentrations of Al2O3 nanoparticles may be of considerable interest in future studies to improve the mechanical properties of PMMA denture base.


Author(s):  
Sung-Geun Kim ◽  
Won-Shik Chu ◽  
Hyung-Jung Kim ◽  
Sung-Hoon Ahn

The rapid prototyping (RP) technology has been advanced for various applications such as verification of design, functional test. Recently, researchers have studied various materials to fabricate functional RP parts. In this research, a nano composite deposition system (NCDS), which can fabricate various nano composites using polymer resins with various nano particles, was introduced. The NCDS is a hybrid system in which material removal process by mechanical micro machining and/or the deposition process is combined. To predict the mechanical behavior of nano composite part made by NCDS, it is critical to understand the mechanical properties of the NCDS material. The NCDS process was characterizes by process parameters such as raster orientation, bead width, weight percent, and curing condition. Tensile strengths and compressive strengths of fabricated specimens with various raster orientation were measured, and various sample parts made of nano composites were fabricated using NCDS.


2018 ◽  
Vol 53 (14) ◽  
pp. 1963-1971 ◽  
Author(s):  
Hossam M Yehia

In this research, 10, 15, 20, and 25 wt.% of WC-TiC-Co particles were coated with a nano-particles layer of copper by the electro-less deposition technique. All the composites were compacted at 900 MPa, and then sintered at 1000 and 1100℃ for 120 min in a hydrogen atmosphere furnace. Nano-composites, which sintered at 1100℃ exhibit relative density higher than those sintered at 1000℃. To investigate the crystal structure and chemical composition of the WC-TiC-Co powders, XRD was used. SEM and EDAX analysis for the sintered samples were performed to investigate the microstructure and morphology of the composites. The relative density, hardness, electrical conductivity and yield stress based on the results of the hardness values were studied. The results revealed that the relative density, hardness, and the yield stress based on the results of the Vickers hardness were improved by increasing the WC-TiC-Co content. On the other hand, the electrical conductivity was decreased by increasing the WC-TiC-Co content.


2012 ◽  
Vol 05 ◽  
pp. 589-597
Author(s):  
MEHRDAD KHAKBIZ ◽  
ALI MOHAMAD HADIAN ◽  
FARSHAD AKHLAGHI

Gas atomized Al (6061) powder particles were used to synthesize nano-structured Al based composite powders reinforced with 2 and 5wt.% of nano and micro sized boron carbide particles by mechanical alloying. These composite powders as well as the un-reinforced Al powders were compacted by cold uniaxial pressing. In order to investigate the effect of consolidation procedures on the properties of the resultant Al - B 4 C composites, a number of the samples were subjected to sintering at 620 °C for 2h while the others were hot extruded at 520 °C with the extrusion ratio of 8:1. The effect of percentage and size of B 4 C on the density, hardness and mechanical properties (such as yield strength, compression strength) of the composites were evaluated and compared with those of the un-reinforced alloy. The fractured surfaces of the samples were studied by scanning electron microscopy (SEM). The results of the present study revealed a higher hardness for the extruded samples as compared with their sintered counterparts attributable to their increased density and decreased matrix grain size. It was also shown that addition of 2 and 5wt.% of B 4 C nano-particles increased yield strength of the extruded samples by 3 and 4 times respectively as compared with the un-reinforced aluminum.


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