scholarly journals Microstructure and Mechanical Properties of Vacuum Hot Pressed P/M Short Steel Fiber Reinforced Aluminum Matrix Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
S. Jain ◽  
K. Chandra ◽  
V. Agarwala
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pure Aluminum ◽  
Average Particle Size ◽  
Energy Dispersive ◽  
Aluminum Matrix Composites ◽  
Average Particle ◽  
Reaction Interface ◽  
X Ray ◽  
Scanning Electron

Commercial purity aluminum powder of irregular shape and ligamental morphology having average particle size of 75 µm was blended with medium carbon steel short fibers having average diameter of 100 µm and maximum length up to 1000 µm. The green compacts of pure aluminum and reinforced compositions were hot-pressed in 10−3 torr vacuum, at 723 K, 773 K, and 823 K for 5, 10, and 15 min durations under 50 MPa axial stress on Gleeble 3800 simulator. Microstructures of the sintered composites have been studied by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The sintered compacts were characterized for densification behavior, hardness, and growth of FexAly reaction interface. Positive densification parameter was achieved for up to 10 wt.% reinforcement fraction. The maximum hardness of 51 Hv was achieved for 10 wt.% at 823 K for 15 min sintering time. The reaction interface was analysed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The reaction interface was found to be composed of Fe3Al, FeAl2, Fe2Al, Fe3Al, Fe4Al, Fe2Al5, and FeAl intermetallics. Growth of the reaction interface was diffusion-controlled which followed a nearly parabolic law with a rate constant of 1.41 × 10−12 m2 s−1 at 823 K.

Studies on conducting nanocomposite with gallium nitride–doped ferrite, part-II

2017 ◽  
Vol 231 (1) ◽  
pp. 53-63
Author(s):  
Rajani Indrakanti ◽  
V Brahmaji Rao ◽  
C Udaya Kiran
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gallium Nitride ◽  
Crystallite Size ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

This article (a sequel to part-I that appeared earlier in the same journal) presents synthesis and characterisation details of conducting PPY-nanocomposite obtained from gallium nitride–doped ferrite and polypyrrole. The GaN-doped ferrite is synthesised by sol–gel method. GaNFe2O3f-PPY composites are prepared by impregnation technique. Using the SciFinder software we could not trace any report in the literature for this synthesised Ga(2x + 2)NFe2(49 − x)O3-PPY nanocomposites. The doped nanoferrite is combined with polypyrrole, an intrinsic conducting polymer, in three proportions by percentage (70%:30%), (90%:10%) and (97%:3%), to obtain two series each of three compositions for the conducting PPY-nanocomposite. The synthesised polymer composites are characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray analysis and Fourier transform infrared spectroscopy. From our studies, it has been observed that the crystallite size of nanocomposites is decreased when compared to crystallite size of GaNFe2O3. The average particle size from histogram is in good agreement with Debye–Scherrer formula calculations. The scanning electron microscopy and transmission electron microscopy micrograms reveal that the particles are varying with the values of X and the percentage of PPY. The shapes observed are Globules,Tetrahedron,Nanorods of short and long lengths. The GaNFe2O3-PPY composites’ spectra revealed the shift in the band in comparison with the PPY spectra. Also, the wavelength is decreased, and vibrational frequency is increased.

IMPACT OF SURFACTANTS ON PHYSICAL PROPERTIES OF BaTiO3 NANOPARTICLES

2013 ◽  
Vol 12 (01) ◽  
pp. 1350003 ◽  
Author(s):  
R. VIJAYALAKSHMI ◽  
V. RAJENDRAN
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Average Particle Size ◽  
Ammonium Bromide ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanocrystalline BaTiO3 particles of about 20–35 nm have been successfully synthesized by using cationic, anionic and nonionic surfactants such as cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and poly ethylene glycol (PEG) via hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy. The average particle size, measured by powder X-ray diffraction was determined to be 20–35 nm and was confirmed by transmission electron microscopy. Spherical-like morphologies were obtained by scanning electron microscopy (SEM) analysis. Optical properties of products were investigated by ultraviolet-visible (UV-Vis) absorption and PL spectroscopies.

Hydrothermal Synthesis of Monodisperse α-Fe2O3 Nanoparticles

2011 ◽  
Vol 236-238 ◽  
pp. 1814-1817
Author(s):  
Hong Wang ◽  
Yan Jie ◽  
Hong Luo ◽  
Xue Feng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Fourier Transform ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Scanning Electron

Monodisperse α-Fe2O3nanoparticles with average particle size of 110 nm were successfully prepared using olyvinylpyrrolidone (PVP) as surfactant via a novel hydrothermal route. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). The experiments results revealed that PVP and the concentration of NH4HCO3have played a crucial role in the formation of the monodisperse a-Fe2O3nanoparticles.

The Synthesis of Nano-Structured TiO2 Ceramics by Modified Two Step Sintering

2012 ◽  
Vol 500 ◽  
pp. 29-33
Author(s):  
Bao Rang Li ◽  
Xin Ming Xi ◽  
Yang Bai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

The nano-TiO2powders with the average particle size of about 40nm were used as starting materials. The compacted powders were firstly performed in Spark-plasma-sintering (SPS) at a high temperature and then sintered in air for hours at a relatively low temperature. The obtained samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed an obvious reduction in grain size was achieved by taking advantage of modified two step sintering (MTSS). The value of the relative grain growth d/do for the samples prepared by MTSS was less than 3.

Structural Characterization of Gallbladder Stones Using Energy Dispersive X-ray Spectroscopy and X-ray Diffraction

2018 ◽  
Vol 21 (7) ◽  
pp. 495-500 ◽  
Author(s):  
Hassan A. Almarshad ◽  
Sayed M. Badawy ◽  
Abdalkarem F. Alsharari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Major Health Problem ◽  
X Ray ◽  
Gallbladder Stones ◽  
Pure Cholesterol ◽  
Scanning Electron

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.

Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Spontaneous Formation ◽  
The Stability ◽  
Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

Effect of TiC on coarsening and macrosegregation of Al–Bi alloys

2020 ◽  
Vol 111 (7) ◽  
pp. 607-615
Author(s):  
Congmin Li ◽  
Yanguo Yin ◽  
Ming Xu ◽  
Jianfeng Cheng ◽  
Lan Shen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Heterogeneous Nucleation ◽  
Self Assembly ◽  
Holding Time ◽  
Energy Dispersive ◽  
Melt Temperature ◽  
X Ray ◽  
Minority Phase ◽  
Scanning Electron

Abstract The microstructures of an Al-Bi immiscible alloy and the corresponding composites containing TiC (1 wt.% and 2 wt.%) were explored for melt temperatures of 800 °C, 850 °C, and 900°C. It was demonstrated that serious coarsening and macrosegregation of Bi-rich minority phase particles occurred, which was slightly alleviated by increasing the melt temperature from 800 °C to 900 °C. By adding TiC particles, the coarsening and macrosegregation of Bi-rich minority phase particles were significantly impeded. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that TiC particles were located inside and on the surface of Bi-rich minority phase particles, exhibiting heterogeneous nucleation and self-assembly behaviour. By properly increasing the holding time of the melt, finer and more uniform Bi-rich minority phase particles were obtained.

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